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Are you still going to post the histogram for the final and the letter grade point ranges????? thanks
Sorry-it completely slipped my mind. Had to go to Oakland today; If I don't fall asleep after getting up at 4:30, I'll do it tonight. CSF
Are the T.A.'s office hours going to be the same for the summer?
They don't have office hours after the quarter is over. Send them an email if you want to talk to them.
CSF
Can we pick up our final directly from you?
From your TA. Or leave three stamps and an address (and your TA name).
CSF
THe My.UCLA is finally working. Not so much of an important question. It gives my grade as "My.UCLA final grade: X", but it also states "official final grade not available yet", but should we count on the my.ucla grade displayed as being the final grade? Do you understand me? Thanks
Yes, it is the final grade. Their software is not working quite right. This is the first quarter they allowed grades to be uploaded. It went into the registrar that way.
CSF
Hey, Once again, another problem. The my.ucla link to "Class Grades" does not seem to be functioning correctly. It just returns me to the main my.ucla page. It's been doing that all quarter since it was put up. Please fix it, I'm getting too anxious. THanks.
I got an automated acknowledgement, but only after the posting of your letter; I think it takes a while to percolate throught the system.Please let me know if it isn't there this AM.
CSF
Hey, Once again, another problem. The my.ucla link to "Class Grades" does not seem to be functioning correctly. It just returns me to the main my.ucla page. It's been doing that all quarter since it was put up. Please fix it, I'm getting too anxious. THanks.
I got an automated acknowledgement, but only after the posting of your letter; I think it takes a while to percolate throught the system.Please let me know if it isn't there this AM.
CSF
The grade isn't on my ucla yet .
I think it takes a couple of hours to percolate through the system. I got an automated acknowledgement early this AM. If they aren't there now, plaese let me know. This is the first tm9e I've used the system and don't know how it works.
CSF
Prof. Foote, the announcement section does not contain information about the final exam pick up, etc. Please post this information again. And can you please post a histogram as well. How are our grades being decided? The extra credit points are not being used as part of the grading total right? (I mean our grade will be measured against the point total excluding the extra credit points right?)
Sorry, I'll do this again. I posted it to the wrong class! CSF
I'm failing to see the "lots" of announcements in the announcements section about where to pick up our tests. All I see is an announcement on accessing the Final Exam key.
Hmm. Let me check. Anyway, grades have just been submitted to my.ucla. I don't know how long they take to see.
CSf
Dr. Foote, I was wondering if possible, if I may provide, you (or the TA's) with postage and an envelope so that my exam may be mailed back to me over the summer. Please let me know at your earliest conveniece as I am leaving Southern California by Friday afternoon. Thanks and hope to hear from you soon. Amine Ale-Ali amine@ucla.edu Amineslk@yahoo.com sid 002761781
Drop it off tomorrow in my office or my mailbox. Have a good summer!
CSF
This is written in response to the friedel crafts question: I had this same concern because even in class when you were in Argentina, you assistant PhD candidate, said that we did not need to worry about that e/withdrawing affect. So, I guess to me this NR is a little unclear because i am thinking that somewhere in some lab experiments the reaction would take place. ....;Could you please clarify what we were instructed on in class when you were gone?
Acylation and alkylation are both subject to the same rule-no reaction with anything less reactive than benzene.
CSf
This isn't really a question. But when i first had problems with adobe acrobat on this page. I downloaded the newest release of the reader software. That might be the problem. YOu could also tell the people who scan the papers, to just not use it. All they do is scan in a .jpg image and then put it on adobe acrobat for no reason. why not just have the .jpg image linked?
It's not a .jpg, it's a Word file they start with. I think they feel that acrobat reader is universal (everyone can get it) but not everyone can read Word. It seems to have caused a lot of trouble this quarter.
CSF
On final problem 6e, the answer was no reaction. However in your book, it only warns us that the limitation of friedel-crafts ALKYLATION fails when there is a strong electron withdrawing group. (805) But then it never was that you can't do a friedel crafts acylation with a strong electron withdrawing.. can't you acylate meta to the nitro?
No, both F/C reactions are subject to that limitatoin. I did mention this in class.
CSF
Hi I am unable to access the final and the final key: Using the chem lab computers in Young Hall 4340. could you please check this. thanks
THat is really annoying. We've been having trouble using them. I'll see if I can figure that out. Did you try the sixth floor labs?
CSF
where and when can we pick up the final exam? thanks Dr. Foote
See lots of info in the announcements section.
CSF
Hi Prof Foote, I'm just wondering if there is any way to find out our grades as soon as you've assigned them? It takes a while before URSA posts up our grades. Also, should we pick up the final from you or from the chem undergrad office during summer?
See the announcements.
CSF
Will the key to the final be posted on the web? What was the answer to the first spec. problem?
Yes.
CSF
When will the final key be posted????????? Thanks
I gave it to them at 11: as soon as they can do it. It has to be scanned.
CSF
where's the final take place? thank you.
CS50
I wanted to know in the photo handout on page 2, why is it that in the first case, the alkene is rearranged but in the last reaction, the alkene is not rearranged. These ?'s refer to thelast two given reactions on the 2 page Adobe photo handout.
These are two different reactions. In the first, the "ene" reaction, the hydrogen is transferred to the oxygen and the double bond shifts (no "rearrangement" because the carbon skeleton doesn't change). The second reaction occurs only with very electron rich alkenes; in most of them, there is no allylic H to shift.
CSF
in MC13, how is it possible to add two Oxygens onto A with just NaOH/HCl?
Hydrolyze the nitrile to a carboxylic acid.
CSF
Prof Foote, how can you go from a phenol to benzene?
You do not have a way to do that.
CSF
Hi Professor:in #16 of the Medicinal Chemistry Hand out,going from step D--->E, how can you get rid of the benzyl group? Also, in #15, what is a good method to get rid of the Carbonyl group? (going from A to the Starting Material that is) Thank You
Hydrogenolysis (catalyst + hydrogen). Benzyl is used as a protecting group a lot because it's so easily removed under neutral conditions. Particularly good for peptide synthesis.
CSF
Hi Prof Foote, on MC 28, in going from D to C, can't you just use CH3Cl instead of the 2 step? also, if you do use the chloroformate, how can you replace that -COOEt group to CH3? Thanks
The two step route gives the secondary amine cleanly. CH3Cl will give a mixture of the unmethylated material, the secondary amine and the tertiary amine. CSF
is it the case that hydrogens on nitrogens will always show up as singlets in HNMR spectras?
In almost all cases yes.
CSF
In regards to the photochemistry reactions 2 page handout, are those the only reactions that we're responsible for as far as the final exam is concerned. Also, for MC 30, is it possible to go from m-cresol to thymol via fried-craf alkyl. Thanks.
The two page handout is specific examples of the chemistry you are responsible for.
Yes, F/C will work. A particularly good way would be to use propene and phosphoric acid.
CSF
does having more resonance structures make a molecule more acidic?
If there are better resonance structures in the anaion than the acid, yes. It's the relative stabilities of the acid and it's anion that count.
CSF
How many spectro. ?'s will there be on the exam? And will they be of similar format and difficulty to that of the 1st exam.
There willbeone combined questionand several short ones. They will certainly not be harder than the first midterm.
CSF
Can Fischer Esterification be used on a phenol to form a protecting group?
No; phenol esters are very reactive because of the acidity of the phenol, so the equilibrium is very unfavorable. Best to use acid chloride or anhydride.
CSF
Hello, Prof. I have a quesiton on medicinal chemistry handout. on #27, step D to E, to take off THP, is it correct to use H2/Ni? also, on the # 30, from thymol to mosisylyte, how do i put esther on the ring? thank you..
THP is normally removed with acid. H2/Ni is good for benzyl protecting groups.
CSf
the midterm II key isnt working...is there any way you can repost it
We've reposted it already. There is some sort of glitch for some machines. I'll try to print a copy tomorrow and put it on reserve in the Chem library. Most people can get it fine; could you ask a friend?
CSF
Can Pt/H2 reduce a carbonyl (ketone) to an alcohol?
Yes.
CSF
Hi, Profssor. On #21 of Med chem handout, in step 9, to change ketone to alcohol, we would use, NaBH4. But how come the carbonyl group of amide stays same and not changed to alcohol as well? Am I supose to protect it with something? if yes, with what? thank you..
Amides are not reduced by NaBH4. You need LAH for that.
CSF
Hello Prof. Foote. Does NaBH4 reduce the carbonyl on the amide? Thanks.
No. You need LAH for that.
CSF
Prof, carbonyl pinacol formation with photochemistry, does the alcohol have to be isopropyl alcohol?
No, this reaction is pretty general.
CSF
Prof., did you ever post preferred problems for chapter 22? Also, will you please announce if you or any of the TA's will have OH on Monday (the times and location please). Thank you before hand.
? We did not cover Chapter 22. I have asked the TAs if any of them are having office hours, and I will post any. I myself have office hours 1-2 on Monday.
CSF
Professor Foote, Does our 3x5 notecard have to be handwritten? Thanks!
No. No optical devices, though!
CSF
Hi. I wanted to know, hypothetically speaking, if we were given a synthesis problem, and say we didn't know what reagents were involved, but we knew the molecules involved to get there, would partial credit still be given.
Hypothetically, probably, depending on what you did.
CSF
Dr. Foote, Can H2/Ni reduce a nitrile to a CH2NH2? Also, are calculators permitted on the exam for purposes of mass spectra as they were allowed on the first midterm? Thanx Amine
Yes. Often used in pharmaceutical synthesis, not so often in lab because it's a pain to use.
CSF
Hi Professor, when is it necessary to use Acetic Anhydride to form a protecting group? For ex., is it necessary to use it when doing a Friedel-Crafts on a benzene that has a functional group with free electron pairs?
Principally with aromatic amines (with at least one free NH). Otherwise they form a complex with AlCl3 that is unreactive.
CSF
Prof, is NH3 strong enough base to deprotonate phenol?
It's pretty close! Phenol and ammonium have very similar pKa. But to do this completely, use hydroxide.
CSF
How can you make an acid chloride from an aldehyde. Thanks.
Have to oxidize to an acid and treat with SOCl2
CSF
Question: Will there be only one Medicinal "Total" synthesis problem for the final, and if so, does that mean it will be the one from problems 13-30? Also, can I please have an A on the final?
Yes. There will be other synthesis.
CSF
Can you tell us what chapters the nomenclature chapters will primarily come from?
The chapters where nomenclature is introduced. You are not responsible for names from the med chem or photochem units.
CSF
Hello, When can you post the answer key for problem set ten?
I'm not sure when they will get it posted; probably not until Monday now. It's frustrating for me too!
CSF
HI Professor, Arent you glad it is Friday? Well, my question is from the handout for week 10. Problem 3. Q: when i see hv should i assume the oxygen could become nucleophilic? What causes the electrons to start moving and is there a predictable order to their movement? thanks
In a photochemical reactions, a carbonyl actually becomes a little electron deficient (like a chlorine atom). The light promotes the electron from an n orbital into a pi*, thus no longer entirely on the oxygen.
CSF
Are the quizzes going to be normalized for each section?
If necessary.
CSF
How many questions will be on the exam? And how much of it will involve nomenclature? thanks
Same proportion of nomenclature as on the hour exams (only from the regular chapters). The final is about like two hour exams. CSF
How many questions will be on the exam? And how much of it will involve nomenclature? thanks
Same proportion of nomenclature as on the hour exams (only from the regular chapters). The final is about like two hour exams. CSF
How many photochemistry ?'s will you include on the exam?Thanks.
A very small number.
CSF
Hi Professor Foote, You had mentioned that a few of the MedChem questions #13-30 may require chemistry that we haven't seen before. I know you're not going to post the answers to these questions, but can you at least tell us beforehand which ones require unfamiliar chemistry? We might get stuck doing a problem and it can be very frustrating to try and find a solution when we are required a use a reaction that we've never used. Thanks! Austin
I've talked about most of the unfamiliar chemistry in class. In any case, I will give you any unfamiliar chem on the exam.
CSF
WHen are the last day for regrades for exam 2.
Hmm. Usually one week after the exam. See if you can contact the TA if there's reall y an error.
CSF
are the sample reactions that you posted the only ones we need to know from the handout??
Yes
CSF
Hi Dr Foote, I was hoping that you had additional copies of ch 15?? could you please bring them in friday?
I don't seem to be able to find them. I can get a couple on Monday. Sorry, this was down until just now.
CSF
Does reacting Aniline with cyclohexanone yield a diarylamine?
Depending on how it's done, it could give an arylimine (Ph-N=(C6H10)) or a di(arylamino) cyclohexane.
CSF
How many photochemistry questions will be on the final exam? Thank you.
Not many.
CSF
HI PROF FOOTE, WHEN WILL THE ANSWERS BE POSTED? ( OR ARE THEY POSTED IN THE CHEM LIBRARY??) -THANKS
They're psoted. Sorry the Q/A was down.
CSF
test
That's working. CSF
Hi Professor: In one of the web-spectra problems (problem #13, Intermediate level 2) there is strong peak that is adjacent to two smaller ones at about 3000cm-1 To what Functional Group does that peak belong?. The compound is C10H15N. Thank You
Those are all aliphatic H. The lower frequency ones probably are alpha to the N. The strong one is just aliphatic C-H stretch.
CSF
In the reactions that we did in class, you used -CN as a Michael nucleophile; however, it is not consided one in the textbook. Wouldn't -CN do a 1,2 addition, not a 1,4? Please explain
Nope, It's a prety good Michael nucleophile; the places I used it were all esters (I think) which aren't too reactive to direct attack.
CSF
Prof., for MC 5, in going to intermediate A, will there be a problem with stereochemistry around the double bond after loss of H2O?
Yes, but it doesn't matter because that's lost in the next step.
CSF
Hi Professor, is there any way you would consider allowing us 2 index cards? Colleen said you allowed that when you taught an o-chem class a while back. There is just so much information. Thanks.
No, 1 is all. you need to focus it down. Using it is more important anyway.
CSf
Hi. When you say that you will only pick 1 question from 13-30 for the mc chapter, does that mean only 1 ? on the final exam will be pertaining to that chapter? Also, will we need to memorize the various nomenclature for that particualr chapter. Thank you.
Only one Q from 13-30 mwill be on the exam. No special nomenclature from that chapter will be needed.
CSF
Professor, How many index cards do we get to use on the final exam?
One-written both sides.
CSF
Hi prof Foote! Just curious about the final exam, will we be able to have a 3x5 card available for use? thanks!
Yes. written both sides.
CSf
is there some place we can pick up the handouts from class if we dont already have them??
My office or in lecture tomorrow. Also the TAs have some.
CSF
Prof. Foote, Can you please move the review session to an earlier or later time on Monday, or another time. Many of us have our physics final from 3-6 on Monday. Also if the high on the midterm was 103, why does the histogram show a person within the 110 range? What are you considering the average of 70 to be? Also considering that it's already week 10, I think it's rather unfair for us that you have suddenly given us 30 problems to do that require a formidable amount of Chem 130A memory- yet during the quarter you told us only to remember rxns that related to the chemistry that we are currently doing, like reduction of a carbonyl after acylation. It wouldn't have been so bad if you had given these awhile back. So can you please reduce the ambiguity of picking any problem form 13-30 to a smaller range. We all have a lot going on this week and next. Please be considerate of this. THANKS!
1. I'll look into this. I think 6 PM may be too late.
2. Read the histogram correctly. 110 is the top of the box, not the bottom.
3. After we have done the first 8 in class, I think you will see that there is not that big a variation in the chemistry.
CSF
When did you say the answer key for the handout would be given??? Will we finish the carbohydrate chapter?
I'll post the answers Thursday. We're done with carbohydrates.
CSF
Are we gonna be tested on the singlet/ triplet etc info on the handout?
Chemistry only.
CSF
Professor, in today's (Monday) lecture, for medicinal chem problem 2, in going from A to B, did the amide go through keto-enol tautomerism and the double bond of the enol then attack Br2?
Yes. We are not told whether it's acid or base catalized, so I assumed acid.
CSF
Are there any problems or book reading after the 2nd midterm?
I will hand out some problems today.
CSF
4 questions: 1) on slide 10 why is n to pi star forbidden, don't we use n,pi star state for reactions? 2)what does spin allowed/forbiddeb actually mean? 3) On slide 36, what is D? 4)what are traps?
Yes; it is very weak in absorption because there is very poor overlap between the n orbital and the pi*. Just because it's forbidden doesn't mean it doesn't happen, just that it's improbable.
CSF
Will you have any problem sets for the handout we were given?
No, except in discussion section. Just concentrateon the few reactions you are give, particularly the ones I wrote on the board.
CSF
Hi Prof. Could you suggest readings to go along with the handout you gave last class? What are the ranges for A's B's from last midterm?
The handout is all you need. Just concentrate on the (few) reactions.
I don't assign grades on hour exams.
CSF
Some strange reaction has taken place which posted the Biochem Histrogram on our website. Anyway, could you post the other statistics for the exam also. Average, SD, and GRADE distribution.
Yup.
CSF
Hi again, I just reviewed the class histogram for midterm 2. It looks as though the exam is labeled as 153B. Could you please verify this?
Right you are. Aren't you glad you aren't in that class? I'll get it fixed!
CSF
Hi Dr. Foote, About the handout given in lecture today, what aspect of this information is relevant for our final exam? In your opening comment today, you said that you would not test us on it. For clarification, could you specify what is testable and what exactly is not? Thank you Sir and have a nice night.
What I said was that the organic reactions would be tested, the photophysics were background. So you should know 2+2 cycloaddition and cis-trans isomerism of alkenes, for example.
CSf
Dear Professor Foote, I was stil a bit confused with the definition of a singlet. You said that a singlet has not unpaired electrons. How is Si on slide 11 a singlet: one electron is at a different energy level. For Energy transfer, does the sensitizer return to the singlet state after it collides with the accepter.
Although the S1 state has electrons that are in different orbitals, they still have opposite spins, so there is no net magnetic moment.
For energy transfer, the sensitizer does return to the (ground) singlet electronic state.
triplet + singlet -> singlet + triplet.
CSf
Could you please post the exam 2 histogram? thanks
I will give it to the voh contact later today; he will post it as soon as possible. CSF
how do we go about getting regrades?
I will post the TA names who graded each question. CSF
Yes I do have the acrobat reader but for some reason some documents open and many don't. For example for this midterm key it says 'can't open file because it is not supported or might be corrupted' What should I do?
I couldn't open the key either; I asked him to redo it. I haven't had a chance to check it (internet access here is not trivial).
CSF
When will the midterm key be posted?
Should be up already. CSF
Hi. Can you fix the midterm 2 key because it is not opening. Thanks.
OK; I'll see what I can do. You do have Acrobat reader? CSF
Dr. Foote, how do you tell if a sugar is reducing or non-reducing. I am looking to see if it is a hemiacetal then it is reducing, but if it is an acetal, because it has a CH3 on the Oxygen attached to the anomeric carbon, then it is non-reducing. Is this a correct way to characterize and classify? Thanx Amine
Correct.
Does Wolff-Kichner also reduce NO2 to NH2? thank you
No, that one is specific for ketones/aldehydes.
CSF
Hi Dr. Foote, How are we supposed to specify reactions and to what details on the exam? Also, do we have to write out all the products formed?
If special conditions are required, you should specify them. In the case of aromatic substitution, it would be >OK to indicate the para product and say "(+ ortho)".
CSF
I am responding to the question asked on Tuesday: What note(s) are being spoken about??? Can you elaborate on why this conversion to the phenol from chlorobenzene works using Naoh. Thanks alot
That is, the students notes on my lecture. The reaction of chlorobenzene with phenol requires forcing conditions and goes through the formation of benzyne. It is not a synthetic method.
CSF
When performing a seperation filter, does it matter what you start with first, after initially dissolving the unkons in ether? For instance, problem 30 of chapter 21 starts off acidifying to seperate the 4-methylalinine first. I chose to start by first adding aqueous base (NaOH/H2O) to first seperate the Phenol. Would this work as well?
In this case, that would work fine as well. If you had more than one acidic compound, it would be better to separate the basic one out first.
Dr. Foote, How do you justify the synthesis of #40 in chapter 20? The methoxy group is overwhelmingly more activating than the methyl group, yet in step 2 of this synthesis, it is the methyl group that will direct the alkyl group to the para position. Although the solution manual acknowledges formations of isomers and it states that the desired one was seperated out, how would we rectify this on an exam. A similar issue came up in class today. A THOUROUGH response would be very much appreciated. Thanks Tookan
Remember that both the methyl group and the methoxy group are ortho AND para directing, so you will get a mixture of products which will have to be separated. The one where the alkylation goes para to the methoxy instead of ortho will not get you to the desired product, so you throw that one away. Nitration of the product of alkylation ortho to the gives the desired product. Things in reality are not always as cut and dry as students want them to be. You will often get mixtures of products. On an exam, you should worry about what will get you to the product in an efficient way. Usually, the desired product will not be the ONLY product.
Hi, Professor. What was the cut off for this exam so far as the chapter 19 material goes? Will we have any spectroscopy related questions? Also, which specific problems should we focus on for this exam from chapter 19, thanks alot.
You should know all the material from Chapter 19. There will be no spectroscopy on the exam.
Hi Prof Foote ~ Today's lecture only covered up to section 24.4. I was wondering if we were responsible for anything after this part because the substitute didn't mention much about it. Thank you ~
You are only responsible for what was covered in lecture for the carbohydrate chapter.
Chapter 21 uses 1.)LiAlH4 2.)H2O to reduce carbonyls to CH2 groups. Can we do this or do you prefer we use Clemenson/Wolf-Kishner?
LiAlH4 reduces carbonyls to alcohols. Wolff Kishner reduces carbonyls to alkyl groups.
You need to use Wolff Kishner if you need to remove the oxygen altogether.
In chapter 21 number 41 part c, the second step of this synthesis creates the carboxyl group on the CH3, but won't the 3rd step H2,Ni reduce the carboxy group as well? In my sythesis of p-cyanobenzoic acid from Toluene, I 1st treated with HNO3/H2SO4 then reduced the NO2 with H2/Ni, then created a diazonium salt w/ NaNO2, HCl, then treated w/ CuCN/Heat (Sandemeyer) and then lastly used K2Cr2O7/H2SO4 to create the carboxyl group. Is this route feasible as well?
H2 and a metal catalyst will not reduce aromatic rings or the carboxylic acid.
It will, however, reduce C-C double bonds, aldehydes, and ketones.
Your route seems feasible as well.
Do we need a calculator for the exam?
Calculators are not needed.
Hi. I don't know if it's just my computer but the problem sets are posted twice instead of the problem set and the key.
Oh my goodness - you are right. I will try to get the VOH people to fix this ASAP.
HI Prof. Foote, you had written that we will need to know nomenclature for Chp. 24, but there are so many different chains and names; which of these other than glucose should we know? Secondly, we didn't cover disaccarides and polysaccarides in lecture, so will we be held reposible for this material?(Here again, there are many types of combinations!) thanks!
For nomenclature of carbohydrates you only reposonsible for the monosachharides that were mentioned frequently in class.
. You do not need to worry about the disaccharides and polysaccharide names. You must be able to tell whether a certain sugar is D or L, alpha or beta, and how to describe glycosidic bonds in all types of sugars.
Hi, I just wanted to know if all of chapter 24 (carbohydrates) is covered on the exam or part of it. If part of it, than upto what point is it covered. thanks
Just the things covered in lecture.
Do we need to know the section on ascorbic acid, disaccharides and oligosaccharides, and polysaccharides for the exam. Nora just briefly discussed maltose and another disacchardie but did not cover the other sections. Please respond as soon as possible. Thanks.
I mentioned several times in lecture that you were not responsible for the parts of the carbohydrate chapter that I did not cover.
HI. I think there's a problem with the link to the problem set answer keys. The answer keys do not seem to contain any answers to the corresponding exercises. Please post the answers if at all possible. Also, which monosaccharidic Fischer projections (p.951-952) do you consider to be important for the upcoming exams (i.e which one's should we memorize in preparation for the exam). Thank you.
I just checked the answer keys, and they work fine for me.
Know the names of the monosaccharides that I mentioned frequently in class.
Hii. I wanted to know which Fischer projections you felt were important in the two pages of the carbohydrate chapter that gives all thos Fishcer projecxns. Thanks.
You should understand what a Fisher Projection in general is telling you - how to determine stereochemistry from
it and how to convert it to chair and Haworth projections. In addition, you should be able to convert from other kinds of representations to Fisher projections.
You should know the names of the sugars I mentioned frequently in the lecture and don't worry about the rest.
Hi, in your note, you convert 1-chlorobenzene into phenol using NaOH. But this is not a good method, right? Should we first nitrate it first? Thank you.
Yes, this is not a good preparative method.
CSF
Professor- we should expect nomenclature on amines on the exam as well as the carbohydrates... Correct?
Yes.
CSF
What does standard deviation mean?
Statistical term for the amount of variation.
CSF
Hey Dr.Foote, In regards to the Chapter 15 homework key, the answers only go up to number 21. Does this mean that is all we have assigned and if not how can i get the answers to the rest of the problems? Thanks
Unfortunately, I donīt have the material with me. Could you email Jeremy McCallum? Also, you are aware that itīs the Chapter 15 handout, bįnot the Chapter 15 in the book?
CSF
hi dr foote, I was just trying to download the discussion sections handouts off the web and none of them are working.
Iīll see if I can get it fixed, but I havenīt yet been able to get email working. Please email Jeremy McCallum; also voh@chem.ucla.edu.
CSF
hi dr. foote-- i was wondering what the standard deviation for the last midterm was...thanks
About 20.
CSF
Hi professor, where can we get the solutions to the problems from the organometallics handout you gave us? we're concerned because we will be responsible for the problems in that handout. thanks
These are being posted; it will take a bit of time.
CSF
Hello Professor, Who is going to write/ design/ create... our next exam? Thanks alot.
It's done.
CSF
Hi Professor, I was shocked that we will be allowed a note card into the next exam. I could understand for the spectroscopy material...I personally dont think that we need this. In having the note card one could actually put every reagent they know and then some on the card. This is not testing our learning ability nor our problem solving ability. I was wondering if you could put this up to a class vote. With all of the reactions in hand, wont this drive up the curve dramatically??? thanks
No, I have done this for many years. It cuts the panic index and the desire to cheat, and is really not much help to those who don't have a good understanding of the material. It also encourages people to organize the material throroughly.
CSF
Hi. Are you going to post the organometallics handout on VOH? Thanks!!
It's too big to post effectively (and there are copyright issues). If you need a copy you can get it from me.
CSF
will our next test cover the handout, ch 22 and ch 24??
The handout, Chapter 21 from page 771 on, Chapter 20, Chapter 21, and Chapter 24 (carbohydrates).
CSF
Professor Foote, Would you kindly provide study questions to the upcoming exam and post it on the web. I thought the extra Spec problems you posted last time were very helpful and it would really aid us to have more practice, on synthesis, most especially. Thank you. :)
Extra questions are being given out in discussion sections.
CSF
How do we know when to reduce using LAH or Fe with HCl? Is there a certain time when we use a specific one or can they be used interchangably?
WIth aromatic nitro compounds, you can use either one. If there is an acid-sensitive group (such as a ketal) use LAH
CSF
what's the deadline for regrades?
Today. CSF
Hi Proffessor, I have couple of questions regarding ch 20. Why can't the Friedel Craft's alkylation occur when the specified groups are attached and also do these groups effect acylation in the same manner? All meta groups do not give Friedel Craft's? What if there is an activating group attached? Last, is para usually major over ortho or this just applies when there is a halide attached? I appreciate it if you can answer these? thank you
By "the specified groups" I assume you mean the long list of electron-withdrawing groups. The F-C reaction is just more sensitive to deactiation than the other reactions; you can't heat because the conditions destroy the alkylating agent. Acylationis also affected.
When there is a war between donors and acceptors the results can be unpredictable.
There are a few cases that give more ortho, but you can assume that para will predominate in most cases (except the Kolbe Carboxylation).
CSF
Hi Dr. Foote, I just wanted to make sure. We are responsible to remember all the reactions that we learned in 130A and apply them again to aromatics? thank you
Yes, more or less. I will be reminding you as we go along. Obviously, the focus is on this quarter's work. But you will need to be able to use all the tools you have.
CSF
Hello Professor Foote. I have two questions. First I can't download the updated schedule for some reason even though I have the adobe reader. The reader is working fine with all the other documents except that one. Second, how do we go about requests for regrades? Thanks
Hmm. Works fine for me. We've had several problems with this recently (particularly with the histogram). I'll see if I can get to the bottom of it. With regards to the histogram, I got the following response, which you might try here too.
"This is a well known problem with viewing pdf files under internet browsers. Adobe suggests not to use pdf browser plug-in. Another thing you could suggest is have the students use the free Acrobat 5.0 reader to view the files."
As for regrades, see the grader. Chris did 1,4 and the extra credit; Jeremy did 2,3,5.
CSF
HI, when will the answers to the problem set be posted?
What problem set? Are you referring to the one in the discussion section? Those will be handed out in discussion.
CSF
I, too, have Acrobat yet I am still unable to view the histogram. It keeps saying "Cannot find color space 2 (CS2)" or something to that effect. Please rectify the problem, if at all possible. Thanks.
They supposedly posted a new version using HTML Friday.
1. Try hitting "refresh" in your browser to make sure you dn't have the old one cached.
2. I'm passing your message on to the netgurus here.
3. It occurs to me that this is the first colorr document I've posted, and that may have something to do with it. Sorry-come to my office and I'll show it to you!
CSF
Hi, I just go ahead and download the adobe again, but still couldn't see it. Maybe it's better if it's in the text form. Thank you.
Try again. They have changed the format. You have installed the Acrobat reader, haven't you? Were you able to view other things like the exam key?
CSF.
I am also unable to view the histogram. I get the error "Could not find the ColorSpace named "CS2" whatever that means...
That's bizarre! Let me find out what's going on!
CSF
I think that it would be much better if you would post the letter grade ranges (for example A 80-100) than post the histogram. Just an opinion!!
I do not assign letter grades on individual exams.
For some reason i am unable to view the class histogram. Could you possibly check to see if it is my system or if there is a problem with the site? Thanks
I can read it fine. It's a .pdf; do you have acrobat reader installed? Have you been able to read other posted materials, which are also .pdfs?
CSF
Hi, can u tell us the point distribution.
Will post.
CSf
Hello. I just wanted to get something cleared up about the exam. The max number of points one could ideally obtain is 118 but the true number of points the exam was out of was 108 points. Correct? Yes or no? Thank you.
Sure.
CSF
Was the exam average taking in the points from extra credit? Because, if it is, then the question wasn't really "extra" it was mandatory, right? Also, can we have a chart of the point distribution and some idea what each test score was on a letter scale? Thanks.
I'll post a histogram. Didn't get the grades until yesterday and had no time then.
As for the extra credit, it all works out the same in the end.
CSF
Hi, Professor. I realizes that you don't assign grades for individual exams, but what would an approximate cutoff for A's and B's be. Thank you.
In general the average is ay the C+-B- border, modified somewhat by my general satisfaction with the level of class accomplishment.
CSF
What I meant by my last question (regarding partial credit) was how are the points going to be distributed? How much credit is given to the labeling of spectra and how many points for a totally correct answer? Personally, i have looked at a lot of spectrums and I can label them okay but I am just not getting proficient at this. thanks
As I said in class, the final structure is a small part of the total. Anakysis of the spectra is tha major part.
CSF
Hi Professor, On the midterm, for one of the spectral problems, what was the 1638 peak? Was it an aldehyde, ketone C=O stretch slightly shifted downfield because of adjacent pi system or was it the C-O of an COH?
1683: conjugated aromatic ketone.
CSF
Hello Dr. Foote, when will you post a key for our midterm? How will the partial credit be determined?
See previous question. Parial crediti is determined for each question.
CSF
are you going to post the key to Midterm 1? When should we expect our tests back?
The key will be posted. It needs to be scanned and that usually takes a couple of days. The TA's have a cumulative exam today, but are hoping to get the grading done by Monday.
CSF
where do we draw the line between strong and medium intensities? (at what %transmittance can we say is strong, medium, or weak peaks for IR?)
Just eyeball it. If there are a lot of alkane H in a molecule, they may outweigh even a carbonyl.
CSF
When looking at the mass spectra, will the parent ion always be designated the "M+ radical dot" symbol? Why does the parent ion already have a radical when that's the molecular weight of the compound before fragmentation?
M+. means there has been one electron removed from a neutral molecule.
CSF
This relates to nomenclature: Professor Foote we have not had so much practice with nomenclature so when you say we know diasteriotopic and enatiotopic what are you referring to cis/trans or r/s? This is for most of us, the first time we have used such terms as para, meta ortho>> thanks
Well, the aromatic nomenclature is new, but it's pretty striaghtforward. What I meant was that the only other "nomenclature" we've encountered is the topicity nomenclature in NMR.
CSF
Hi. For chapter 19, #45 was assigned but that question relates to section 19.6, for which we are not responsible. Will 19.6 be covered on the exam.
No. I had originally intended to finish the chapter.
CSF
Will the nomenclature questions pertain solely to the aromatic chapter? Thanks.
That's all the nomenclature we've had. (But of course, you do know diastereotopic from enantiotopic, don't you)?
CSF
Can we tell if a molecule is cyclic by looking at the IR; is there a region that will indicate a ring (but not aromatic)?
No, except for shifts in the carbonyl for smaller rings. Of course lack of a methyl group may indicate a ring.
CSF
Hello, Professor. On the exam, will you give us a structure and expect us to draw our own peaks on the Hnmr that adequately refers to the structure. Thank you.
That would be one possible type of question.
CSF
Hello Professor, could you handout or post the quizzes ( all variations of). It seems that not all discussions had the same quiz and I would like to get more practice. thanks.
I will try to arrange that. It takes a while to get stuff scanned, though.
CSF
Is there an equivalent of the Frost circles for multicyclic conjugated systems?
No. Things get more complicated there. However each ring can be considered separately to some extent (a cyclobutadiene fused to another ring is still going to be terrible).
CSF
On the 3x5 cards- can we type on the notecard insteading of actually hand-writing it? (ie., cut and paste)
Fine by me. You can print it in 3 point type if you can read it! CSF
Dr. Foote, On page 608 of the text in Brown and Foote, we are given a Mass Spectrum. What causes the peak at 60 in the mass spectrum of Butanoic Acid? Thanx. Amine
This is an even mass peak, M-28, so it would have to be either loss of ethylene or loss of CO. Ethylene would correspond to a McLafferty cleavage, and that's what it is.
CSF
hi dr foote. could u let us know what the format of the exam will be and the amount of problems? as well as for the graphs what will be included? (ie the integration and clarification on the mulitplicity of the peaks ) thank you
Check for sample problems on Wednesday.
CSF
Hi, did you say you would post up answers to the handouts? Thank you.
The MS ones are up. I hope to get the IR ones up tomorrow.
CSF
Dr. Foote, What happens in an IR spectrum when you have an electron withdrawing group next to a CH2 group. Does its wave nuber increase or decrease relative to a CH2 sitting next to another CH2? Thanx. Amine
That is not so clear in the IR (as opposed to NMR). The one place where you can really see an effect is on CH3 next to carbonyl, which is unusually strong and prominent. But this is not very useful for your purposes.
CSF
For the exam, will you be providing us with H-nmr, C-nmr, and IR spectra, or are we expected to put this vast resource of essential data on a 3*5 notecard? Also, page 608 of the text in Brown and Foote, we are given a Mass Spectrum. What causes the peak at 60 in the mass spectrum of Butanoic Acid?
Put what you can't remember on the card. You should be able to recognize key areas without reference to the card (e.g., where's a carbonyl in the IR? Don't use too much detail. The structures will be overdetermined!
Dr. Foote, In chapter 17 number 20a page 676, we are given hnmr and cnmr data. The answer in the solutions manual proposes that this compound for a, is a carboxyllic acid. However, what I am coming up with, is an ester, in which our O is attached to an aldehyde group. This, to me, makes more sense because the h-nmr data given for a 2H group, matches up more closely with a CH2 group near an Oxygen, such as in an ester, rather than a CH2 group near a carbonyl, as the answer proposes. Thanx. Amine
You are absolutely right. The best structure I can come up with is isobutyl formate, (CH3)2CHCH2-OC(=O)CH; the formyl H is what is absorbing at 8.08 ppm. Your analysis is perfect!
CSF
For sec. 19.2 part E. How can we tell if we should convert a molecule to anion or cation to obtain aromaticity? It seems like 3 C -- cation, 4 C -- anion, 5 C-- cation.... Thank you.
You need to get 4n+2 pi electrons: 2, 6, 10, etc; so for 3C: cation (2-1electron), for 4C you would need a dication or dianion (4-2 or 4+2 electrons), 5C: anion (5+1 electron).
CSF
For question 12-2. Why is C3H5. How and do we need to figure out how many H's? I understand it's C3 b/c it loses one more Carbon. Thank you.
I think you're referring to Fig 12.5 on p 444. the 41 peak is loss of another methyl from the 56 peak. exact mechanism isn't so clear.
CSF
Can you forecast what the cut off will be for midterm 2? I am a little surprised that we are still covering new material for this coming weeks exam. Will our last lecture for midterm one be on Monday? Will we have any reviews on Wednesday or next week?
There will be some review on Wednesday. I will let you know Monday exactly what will be covered.
CSF
Hi Prof. Foote, Could you please have a practice midterm made as well as some c-nmr problems since we haven't really practiced those as much as h-nmr? A Practice one would really help us know what material we need to review more. Thanks!!
I will do some practivce problems on Monday. there are old midterms available with keys at the 130B winter page (http://voh.chem.ucla.edu/vohtar/winter01/130B/) and spring 2000 (http://voh.chem.ucla.edu/vohtar/spring00/130B/) pages.
csf
I just need to know how to be enroll in these online classes? thanks.
These are not really online classes. These are support for regular classes at UCLA.
C. S. Foote
Hello. I wanted to know why having a stronger bond corresponds to a higher frequency. Isn't a stronger bond lower in energy because that's where the greatests stability is, and since energy is proportional to frequency, wouldn't a bond having more s character have a lower frequency. Thanx.
Think balls and springs. If you use a stronger spring, the balls move faster, or at a higher frequency.
CSF
Hi Dr. Foote, I've noticed that problems suggested for Ch. 13 with NMR spectrums to be analysized are not very clear. Specifically, I had trouble determining how many peaks are in certain signals (i.e., 13.21 Compound E). For the exam, will we have the luxury of having the signals zoomed in, in order to calculate how many peaks there are? Thanks.
You are right that many of the peaks are hard to see. The exam questions should be much clearer.
CSF
Hi Dr. Foote, I've noticed that problems suggested for Ch. 13 with NMR spectrums to be analysized are not very clear. Specifically, I had trouble determining how many peaks are in certain signals (i.e., 13.21 Compound E). For the exam, will we have the luxury of having the signals zoomed in, in order to calculate how many peaks there are? Thanks.
You are right that many of the peacks are hard to see. the exam questions should be much clearer.
CSF
Hi Dr. Foote, I've noticed that problems suggested for Ch. 13 with NMR spectrums to be analysized are not very clear. Specifically, I had trouble determining how many peaks are in certain signals (i.e., 13.21 Compound E). For the exam, will we have the luxury of having the signals zoomed in, in order to calculate how many peaks there are? Thanks.
You are right that many of the peacks are hard to see. thte exam questions should be much clearer.
CSF
how is vibrational frequency related to the amount of s-character a molecule has?
The more s-character, the stronger the bond; the stronger the bond the higher the frequency.
CSF
Hello Dr. Foote, which problems would you suggest for chapter 19, etc. Thanks.
I'll post an announcement about this shortly.
CSf
Hi, Professor. I was wondering why some textbook problems were excluded from you rlist of recommended problems. Are they impertinent to the topics at hand. Thank you.
No, people want a list of "preferred" problems. The others are also useful.
CSF
So, will you ask 'H coupled C NMR questions on the exam? If so, so we interpret as 'H NMR? Thanks.
I might, but they will be quite clear.
CSF
So, will you ask 'H coupled C NMR questions on the exam? If so, so we interpret as 'H NMR? Thanks.
I might, but they will be quite clear.
CCF
What's 'H-coupled C NMR? What's the difference between it with decoupled C NMR? Are we suppose to know this? Thank you.
In the raw 13C nmr, the carbons are split by all the hydrogens attached to them -so CH3 groups appear as quartets, for example. Normally we decouple so the peaks appear as singlets. But you lose information that way, so sometimes we would look at the spectrum using special partial decoupling techniques which allow seeing the multiplicity, or we use DEPT, which gives the information abother way.
CSF
Prof Foote, In chapter 12 and 14, are there any certain sections of the chapters which we can omit from reading?
You should read all the sections. The sections on UV will not be emphasized. Interpretation of spectra will be the main focus.
CSF
Hello Professor, I dont recall us going over Ultra-violet spectra in lecture...problems 14.14 and 14.15 were assigned and so was the reading for UV on pages 516-519...My question is: Will this be a part of our exam and are you going to cover it in lecture? Thanks a lot.
Yes, I'll cover it briefly (tomorrow). It will not be a big part of the course.
Hello Professor, I dont recall us going over Ultra-violet spectra in lecture...problems 14.14 and 14.15 were assigned and so was the reading for UV on pages 516-519...My question is: Will this be a part of our exam and are you going to cover it in lecture? Thanks a lot.
Yes, I'll cover it briefly (tomorrow). It will not be a big part of the course.
Hi. Do you expect us to know nomenclature for the exams. Thank you.
Yes, in general, though it won't be specifically tested except where it's introduced (aromatics and amines). But you need to be able to write a compound if its name is given. CSF
Hi, Professor. If we were simply given an 1H NMR spectra, would we be able to matter-of-factly determine whehter the disubstituted constituents were ortho, meta, or para. Thanx.
If the chemical shifts were different enough, maybe (often the shifts are too small). Para: only two types of H; two doublets result. Meta: 4 different H (if substituents are different; can be complex pattern, 3 if subs are identical; ortho: 4 different H (if substituents are different; pattern can be complex); 2 different if the same; pattern complex but symmetrical.
Not always trivial.
CSF
Could you post the answer key for week #2 homework assignment, some of us were unable to get one after class because we had to rush out of friday's lecture and run to another class far on the other side of campus.
Gladly, but it will take a couple of days. CSF
Hi Prof. Foote Just for the sake of clarification, on the tentative schedule it says you are going to cover MS (chap 12) then IR (chap 14). Are we going over IR first instead, then MS afterwards? Thank you.
As you have noticed (and as the revised schedule now posted shows), we're covering IR first.
CSF
On Wednesday, 4/11, you went through the interpretation of some example spectra. I was wondering how you figured out how many H's each peak represented. I didn't see any integration lines or aids that would help us deduce the number of equivalent H's per peak and I wondered if the integration was done earlier and just not shown. Were they just a given in the example?
Right, I gave you that information.
CSF
professor...what bk. problems should we work on for ch. 14... thank you...
I'll try to post these tomorrow.
CSF
Dr. Foote will you hold review sessions and/ or make up a nice review sheet/ guideline for the midterm? thanks you.
I will probably hold a review session (which will be largely question and answer).
CSF
Hello Professor, I just tried to email you confidential but somehow it is not working. I wanted to let you know that during and after lectures I feel very confused and disoriented. I cannot see the slides nor the tutorials being used. I cannot distinguish the doublets, triplets etc. I cannot see the difference between the coupling signals and the individual H signals. Our exam is rapidly approaching and i am lost. Can you give me and maybe others who feel like me some practical advice for success in your class?
If you want to mail me confidentially, just use regular email. I got too many "confidential" emails from people who had forgotten to include their emails, so ther was no way to reply.
1. Come to office hours.
2. run the tutorials yourself in the computer labs.
3. do as many problems in the back of thebook as you can.
Where are you sitting? Up front I hope. There does seem to be a problem with the size of projected material in the back of the room.
Have you had your eyes checked recently? It's possible that you may need some correction. Just a thought.
CSF
Hello Professor, I just tried to email you confidential but somehow it is not working. I wanted to let you know that during and after lectures I feel very confused and disoriented. I cannot see the slides nor the tutorials being used. I cannot distinguish the doublets, triplets etc. I cannot see the difference between the coupling signals and the individual H signals. Our exam is rapidly approaching and i am lost. Can you give me and maybe others who feel like me some practical advice for success in your class?
If you want to mail me confidentially, just use regular email. I got too many "confidential" emails from people who had forgotten to include their emails, so ther was no way to reply.
1. Come to office hours.
2. run the tutorials yourself in the computer labs.
3. do as many problems in the back of thebook as you can.
Where are you sitting? Up front I hope. There does seem to be a problem with the size of projected material in the back of the room.
Have you had your eyes checked recently? It's possible that you may need some correction. Just a thought.
CSF
Dr. Foote, which problems would you suggest we try for chapters 12 and 14? thank you.
I'll announce these very soon. CSF
Dr. Foote, Should we read Ch12 Mass Spectroscopy, or Ch14 Infrared Spectroscopy of the text for Fridays lecture? The schedule seems to have some conflicting information. Thanx. Amine
CH 14. Sorry! CSF
Hi, Professor. I was wondering if you could post the office hours of all TAs on the web. Thanx.
In the process. Just got then. CSF
Prof. Foote, Are we allowed to go to any discussion section or does it have to be the one we are enrolled in? And are you going to announce quizzes ahead of time? Thanks.
Because there will be quizzes in the discussions, you should stick with one. The TAs will announce the quizzes. CSF
what are the hours that we can use the computer labs for the tutorials? Thanks
in the 6th floor 9-5 M_F. They are also now in the learning center on the 4th floor south wing; they are open longer hours. I'm going to post a notice later today. CSF
Hi Prof. Foote, I have an idea that is not quite clear to me. In the lecture you mentioned that the Chemical Shifts are "additive", can you re-elaborate on this? It will be great if you can also give an example. Thanks!
If a CH3 group appears at 0.9 and a CH at 1.5 ppm, and a CH3-O is at 3.5, you can expect a CH-O to be around 4.1. Or add the effect of O and C=C. CSF
Hi Professor, I was just wondering if I could join your honor's section. Please let me know when it is convenient for everyone to meet. If not, I was wondering if an honor's contract on an individual basis would work out. Thanks, Meera mgupta2@ucla.edu
I'll choose a time today and will get back to you. CSF
Professor Foote, I have couple questions: 1. DO we need to memorize the J values for teh test? 2. Using the molecular formula and H-NMR, how can we establish if the structural formula is cyclic or not? Any hints? Thank you for your time.
You will need to have a good feeling for J values, maybe not the exact ones. You should certainly know cis and trans alkenes. If there are no alkene hydrogens or carbons, but a deficiency of H, you probably have a ring. Using 13C spectra you can count the sp2 carbons. CSF
Hello Professor, Which problems for chapter 12 and 14 etc would you recommend for us to work on? thanks
I'll get back to you on that later this weekend. CSF
Hi Professor. Several of us went down to 6096 right after lecture today to try the tutorials. But there was something wrong with the program and it was not working properly. Is there another computer lab that has this tutorial? Thanks.
Yes, I am really sorry about that, apparently they only installed it on the Windows machines and it's not working there. It is now on all the Macs and working fine; they were supposed to have installed on all the Machines last Monday. I had not tried the Windows version on the beta CD I have. I don't know if it's the installation or whether the Windows version is broken. Anyway, It's there now. My apologies. This is very new, and we're feeling our way. CSF
Prof, are there any assigned homework problems or are we just supposed to practice all in those in the book? Are there any questions we should specifically look at? Regarding the table of chemical shift, will we be responsible for memorizing the table, or will we be given one in the exam? Thanks
I will give out some suggested problems; do all in the text, and as many additional as you have time for. Structure problems are the key. It would be very good if you could recognize key chemical shifts. CSF
Yes, it does working!
The reason it wasn't working is that the need the class roster to enable the login feature, and the rosters weren't available until today. CSF
Hello Professor Foote, I just wanted to ask if calculators will be permitted or necessary for your exams?
Pronbably wil not be needed. No infrared capable devices, though. CSF
Hi Professor Foote, I have noticed that on the week where a midterm (actually for both) will take place, the days are Tuesday, Thursday and Saturday. This is rather strange because there are no lectures on Tuesdays and Thursdays. Would you please clarify?
Errors; the miterms are Fridays. A corrected syllabus is being posted. Sorry about the delay in answering this; they changed my password! C. S. Foote