Organic Chemistry

I just started my first semester of orgo and I have a question about bond rotation and determing how many atoms lie in the same plane.

For example, for the following molecule, my professor said that the 6 H attached to the sp2 carbons lie in the same plane. But I don't understand why... considering that there are single bonds between each of the double bonds and triple bonds, isn't there rotation along these single bonds? If rotation exists, then the only hydrogens on the same plane would be those belonging to each individual double bond.




If anyone could explain why there are 6 hydrogens in a plane in this molecule I would be very grateful.

Hey guysss. First time poster; long time lurker. Anyway, i'm in my second (and LAST!!!) semester of organic chemistry and i'm having issues with a concept.

So basically we did a lab where we took sucrose and put different concentrations of acid in it and measured the rate of optical rotation. Right. So now we're doing questions to understand and i'm stuck on one. Here it is:

"Discuss the effect of concentration of an acid catalyst on the rate of reaction".

My thoughts: Ok, please don't laugh if this is horribly wrong. I know that a stronger acid has a faster rate of reaction in terms of hydrolysis. So what my thinking was that a strong acid dissosciates 100% (or is it like 99%..man it's been a while since this stuff) whereas a weak acid does not. Therefore, a strong acid can donate a proton (ie: H+) more readily than a weaker acid. So, then the H+ could attack the bond within the sucrose and cleave it (by taking the -OR group out and replacing the -OH from the water already in solution) better? Like what I mean is that the H+ is so seperated from the A- group that it just attacks better than a weaker acid. (wow, my chem terminology sucks). Is this even close to right? Haha.

And another one:

"Reason for the observation of pH dependance". Does this just go back to the idea that a lower pH has more protons floating (..err..) around so it can cleave the linkage better than a higher pH with less protons around?

Arghh.

Last one:

"Why isn't the reaction base catalysed?". Umm. This one i'm stuck. The only thing I can think of is that there's really no where to go? Like the proton can attack the -OR group on sucrose and break the bond but where can A- go? I don't see how it COULD go anywhere.

Sorry, I tried to include my thinking..as bad as it was =(.

Thanks in advance!!

x-posted =D

Hi,

I'm working on evaluating a total synthesis paper for my advanced synthetic organic class and I need to understand the reaction involving BEt3. I think this compound should be called triethyl boron, but searching sigma-alrich for this name only gives triethyl borate which is not the same compound.

It appears to be a catalyst in the reaction between an aldehyde on one molecule and the iodide on another molecule. This is an addition reaction where the end product is the carbon of the aldehyde carbonyl bonded to the carbon of the iodide carbon, where the carbonyl of the aldehyde has been reduced to a secondary alcohol in the new carbon bridge between the two molecules.

I'm not sure if BEt3 is simply acting as a lewis acid, it seems like this reaction is too odd for that to be the case (two carbon electrophiles creating a new bond) ....

Anybody know anything about this, maybe know of a source where I can investigate it more thoroughly? I am receiving "Modern Synthetic Reactions" by Herbert House via an interlibrary loan system, but I'd like to try to find another source on this reaction in case House has nothing to say about it.

Any help is appreciated.

I am trying to synthesize a grignard reagent using the following

( GRIGNARD IMPURITIES??? what is that??? Cross posted because I have no idea what I am doing in chemistry at all )

In a synthesis reaction for amyl acetate


I used


Acetic acid + Amyl alcohol --->
Amyl Acetate + water

Sulfuric acid was added to catalyze the reaction and excess acetic acid was added to make the reaction shift right to favor the product

1. added amyl alcohol and acetic acid (excess) and refluxed
2. then we used the separatory funnel and added
a. water then removed the aqueous layer and kept the organic layer
b. NaHCO3 then removed the aqueous layer and kept the organic layer
c. NaCl then removed the aqueous layer and kept the organic layer

3. then I added a drying agent
4. then I did a simple distillation.


• Acetic acid is removed when NaHCO3 to form salt and water
• NaCl is removed when it reacts with water to dissolve in it and leaves when the water is removed using the separatory funnel and the drying agent


I was wondering how is sulfuric acid removed from the experiment? Did it also react with NaHCO3 to form a salt and water?

Huge problem that I've done and showed all the calculations and formulas to, but I can't get the final answer. I did the entire questions and showed all the steps but logically to me the answer doesnt seem right. Desperately needing help,i'm been staring at my calculations for hours and i'm really sure it's right, but I dont know why molar ratio doesn't work for me I think.



( Work and question all here )

Hey guys, I am not sure if I wrote this right in my notes. So I believe I know the answer, but I want to make sure.

Which one of the following does not react with benzoyl chloride?
1. NH₃
2. CH₃NH₂
3. (CH₃)₃2NH
4. (CH₃)₃N


I believe the answer is 4, because of the steric hindrance. I would like to make sure! Thanks!

Another question:

Which one of the following is not a good way to make ethyl acetate.
1. CH₃CO₂H and CH₃CH₂OH with H₂SO₄ as a catalyst
2. CH₃CO₂H and CH₃CH₂
3. CH₃COCl and CH₃CH₂OH with pyridine
4. (CH₃CO)₂O and CH₃CH₂OH with H₂SO₄ as a catalyst

I have figured out the reactions and have a cross between B and D. In doing suponification forwards, the transformation from the intermediate to the actual anion is an irreversible step, which is what makes me think you can't go the opposite way, which makes me think this reaction won't work. On the other hand, D forms the ester with acetic acid. What you think?

can any one get these synth. comm. papers

1990, 20, 1473 + 1978, 8, 427

my e-mail addy is w.draffin@reading.ac.uk

cheers guys

W.

I am having problems with this reaction. Do each of the additions go to the same ring or do they go to the opposite ring? Appreciate the help!

Hi guys i'm trying to remove a phenyl sulfone from a cyclic secondary amine, there is an alpha dimethyl functionality and an ester gama to the sulfone. I've tryed to remove the sulfone with Li NH3, Na/Hg and Raney nickel to no avail - any other sugestions

cheers W.

The nitration of chlorobenzene occurs @ the ortho- and para- positions. Is this because chlorine, which is a halogen is an Ortho-Para director?

However, my notes said that Ortho-Para directors are -OH, -OR, -NH₂, -NHCOR, -R, -X    **With the exception of halogens(-X).

This is very confusing, either my notes are incorrect or there is another explanation for the orientation.

Help me! =)



x-posted

I am a chemistry novice!

There's something that I don't know about this question.

Calculate the number of moles of NaOH per litre in a 0.1022N NaOH solution.

What's 'N'? Nolarity? Or Nolality? Or something like that? How do we calculate the moles out of that?


Thanks!



x-posted

What is the density of trichloroethylene?

The answers I got from wikipedia is 1460 kg/m³, but what is temperature which the value of density is determined?

Any guides for finding its density in room temperature (25^oC)?





x-posted

• Is is necessary for Segment B to be an alkyl group?
• Since it is drawn in the zig-zag format, does it mean that it's a very long straight chain? Or can it be a ring?
• How do we convert a straight chain into a ring compound? Eg. hexane to cyclohexane?

I'm doing some kind of organic chemistry project, and these questions are hindering the progress! Any help will be greatly appreciated!

Thank you, people!



x-posted

I've acetylated D,L-phenylalanine with acetic anhydride, and the acetylation occurs at NH₂ and not at the carboxyl group. I know that the carboxyl group is a weak acid, but does anyone know WHY acetylation occurs on the amine group of D,L-phenylalanine instead of at the COOH?

There has been a lot of concern in the media about how, in certain soft drinks, benzene is formed from a reaction between benzoic and ascorbic acids. I eagerly tried to draw the mechanism for the reaction, but didn't succeed. Any hints where I should start? I guess the first step is when the carbonyl oxygen of the benzoic acid gets protonated. That's where my skills stop :)

What different methods would you guys suggest for reducing a nitrile in the presence of a boronic acid? The starting material is meta-cyanophenyl boronic acid, and the product I want is meta-(aminomethyl)phenyl boronic acid.

hi guys i'm writing a paper for ASC but it appears to be about the only wiley journal my uni doesn't subscribe to, could anyone email me a couple of articles so i can check out the writing style my email is w.draffin@reading.ac.uk - cheers W.

Since there's no way to convert an alkane to alkene then to an alcohol..Correct me if i'm wrong!

So, is there a way to convert methane into methanol?