Sciencemadness Discussion Board

carboxylic acid functional group

Slimz - 3-10-2007 at 07:36

i was reading in different forum about converting a carboxylic acid functional group into an acyl chloride functional group by exposing it to thionyl chloride.

I was wondering if someone could explain the process in a little more detail and exactly what is happening. I have tried to research this but have reached a dead end.

If im not mistaken you should end up converting a "whater acid" to to a "whatever acid chloride" thus making that molecule receptive to amine.

I may be way off but im doing my best to understand this process.

[Edited on 3-10-2007 by Slimz]

solo - 3-10-2007 at 07:53

Acid chlorides can be converted back to carboxylic acids, converted to amides, converted to esters , acylated to make ketones and formation of aldehydes by reduction.....this information can be found in any organic chemistry book , so read and read some more, there are many organic chemistry books in the library here in the forum as well all over the net.........................solo

More acid chloride reactions....,

[Edited on 3-10-2007 by solo]

[Edited on 3-10-2007 by solo]

Slimz - 3-10-2007 at 08:06

ok thanks.. the next question is where do i get thionyl chloride...or where do i get some sulfur trioxide and sulfur dichloride

BTW here is the intended reaction (this shows only the effected part of the molecule)

[Edited on 3-10-2007 by Slimz]

1.jpg - 9kB

solo - 3-10-2007 at 08:20

Now you're off topic.....there are many threads on the subject both the synthesis and industry uses........ use the search engine .......solo

Slimz - 3-10-2007 at 08:25

how can I be off topic, its my topic. I understand the UTFSE part.. but its not off topic..

Nicodem - 3-10-2007 at 11:13

Is that supposed to be a retrosynthetic arrow or a reaction arrow? It does not fit the standards for any.
If it is retrosynthetic, then you might consider alternatives to thionyl chloride. Of course, if that is just part of the structure (you did not mark the deleted part), nobody can help you with any advice since you did not provide the entire structure. One need to see the whole with all the functionalities present or else the discussion is just worthless guessing. But already from what is visible one can exclude SOCl2 as the best option since it would most likely lead to complete racemization of the chiral centre alpha to the carboxylic group and possibly also other unwanted reactions.

PS: You really need to UTFSE by default before posting.

stoichiometric_steve - 3-10-2007 at 12:41

i see this guy posting crap all over the place, which he could have solved buy just reading basic oc books. this is offending.

jam640 - 3-10-2007 at 12:45

Looks like someone looked up lysergic acid amide on teh wikipedia and did some photoshoppin'...
Wicked skills! :o

chemrox - 3-10-2007 at 23:26

I'm fucking tired of this too... This is not a place to get someone to tell you how to make drugs or where to buy reagents. Sometimes a particular aspect of a drug synthesis might be discussed as a way of talking about a reaction or synthetic challenge. There's no challenge in anything you're asking here. I think you've been warned about this. You can't learn chemistry overnight but if you were sincere in wanting to learn there would be help available. Consider most evryone here has taken courses where hundreds of reactions on flash cards were memorized, studied and developed to understanding. There's a certain jealousy here about preserving the intellectual integrity of the forum. When you waltz in asking how to make this or that it brings down the whole atmosphere. You don't have to be a chemist. You just have to want to learn and try to use the resources available to you. It's lazy and annoying to ask where to buy a particular reagent. It's intellectually enervating to ask us how to make a carboxylic acid chloride. These are things you could have looked up. The admins have been patient to a fault with you. Man up and get a grip!

Maya - 4-10-2007 at 02:46

slimz wrote


converting a carboxylic acid functional group into an acyl chloride functional group by exposing it to thionyl chloride.

Yo, thionyl chloride will destroy the delicate backbone of that molecule slimz. Most people up to the 90's use a milder reagent like POCl3 to convert to the acid chloride. And even better ones now with milder and more efficient yields than before.

maniacscientist - 18-10-2007 at 08:51

Thionylchloride is very good in doing so, you just need to take your carbonic acid and dissolve it -if neccessary-in an appropiate solvent (acid no alcohol!) and add the stoichiometric amount of thionylchloride.

the mechanism is R-COOH + SOCl2 -> R-COCl + SO + HCl

[Edited on 18-10-2007 by maniacscientist]

jam640 - 18-10-2007 at 09:17

Carbonic acid is carbon dioxide dissolved in water.
And that is not a mechanism, but a chemical equation. And it is wrong.

maniacscientist - 18-10-2007 at 09:22

I beg your pardon you´re right and english is not my mothers tongue. in my language is´t carbon acid and so is the right translation I should have known .
The equation is right, except it should read SO2.^^ bit confused at the moment.^^:blush:

Nicodem - 18-10-2007 at 09:31

Still that is not a mechanism. And the solvent used must be aprotic and not an acid. Besides it was already said that thionyl chloride does not work in that idiotic above example of lysergic acid so there was no need in claiming that it "is very good in doing so".
English is not the mother tongue of many members here, including myself, but that is not an obstacle from using a spell checker and a dictionary.

maniacscientist - 18-10-2007 at 09:33

Who was talking about LSD, this is redicoulus since this fragile molecule decomposes with minute amounts of chlorine....

Nicodem - 18-10-2007 at 09:35

Why do you reply to threads you have not even bothered reading first? :(

stoichiometric_steve - 19-10-2007 at 10:41

it is awful to see how dumbasses are attracted to this forum as of late.

Slimz - 23-10-2007 at 07:25

Upon further research i have found that there are indeed better more efficient ways of accomplishing what i was interested in accomplishing using chemicals that are easier to obtain.

AKA converting to hydrazide and reacting with sodium nitrite.

[Edited on 23-10-2007 by Slimz]

Maya - 23-10-2007 at 08:01

That one is very old literature , actually it was in the original lit.

There are better ways still grasshopper if you look at the most recent of literature.......nice try tho,

Slimz - 26-10-2007 at 12:45

Maya, maybe you could PM me something more specific.

Maya - 27-10-2007 at 00:54

nope, not gonna tell ya how to make something certain authorities frown on.

I will tell you the hydrazide you lose half your starting material right off the bat as it is converted 50% to the iso form.

maybe we'll make a chemist outta you yet, look at my previous post