[Karina_Kilmetova]

Hello dear chemists! I have a problem. I can't find an article on a particular topic. Subject: the synthesis of isocyanate by the reaction of diphosgene with a glycine ester hydrochloride. I was searching on Scopus, Science Direct, but I couldn't find. Maybe someone could help me? I would be very grateful. Sorry for mistakes in construction of sentences. I don't know much English.

[AWK]

Try serching chemical name trichloromethyl chloroformate or more generally chloroformates.

[Hunter2]

Hello dear chemists! I have a problem. I can't find an article on a particular topic. Subject: the synthesis of isocyanate by the reaction of diphosgene with a glycine ester hydrochloride. I was searching on Scopus, Science Direct, but I couldn't find. Maybe someone could help me? I would be very grateful. Sorry for mistakes in construction of sentences. I don't know much English.

In my diploma work I had to synthesies OCN-(CH₂)_xCO-Cl by using ß-Aminoacids and Phosgen.

[Karina_Kilmetova]

Hello dear chemists! I have a problem. I can't find an article on a particular topic. Subject: the synthesis of isocyanate by the reaction of diphosgene with a glycine ester hydrochloride. I was searching on Scopus, Science Direct, but I couldn't find. Maybe someone could help me? I would be very grateful. Sorry for mistakes in construction of sentences. I don't know much English.

In my diploma work I had to synthesies OCN-(CH₂)_xCO-Cl by using ß-Aminoacids and Phosgen.

Unfortunately, I need a reaction only with diphosgene. I need a method of carryng out a reaction. But I can't find! Oh...

[rolnor]

You have a aminoacidhydrochloride, dont you need som base? Dry pyridine perhaps?

[phth]

You must add 1 equivalent of base for 2/3 equivalent of diphosgene, 1 equivalent of unprotonated amine.  The reaction must be done carefully.. Wny not just use triphosgene?  This stuff is extremely toxic.  The precautions I took to handle Triphosgene is to put the solid into a tared dry flask in a glove bag, and weigh it.  Next bubble the argon line through a concentrated solution of NaOH.  The key to getting this reaction to go is to add phosgene to the amine very slowly (30 minutes-1 hour), ant 0º.  Adding over 5 min will make the reaction fare too exothermic.  Often I see people use activated carbonates, but my opinion is that they are a waste of time due to an extra purificaiton step, and no benefit in % yield if the experiment is done correctly.

[Optimist]

I think it's better to synthesize isocyanates using triphosgene instead of diphosgene/ phosgene. The advantage of using triphosgene because it is less toxic compared to phosgene/diphosgene and exist in solid form at room temperature.

Simply dissolve your amine (1eq) in dry DCM and add triethylamine (TEA) base (2.5eq) at 0C under inert atmosphere. Add triphosgene (0.33eq) dissolved in anhydrous DCM over a period of 2.5 hour dropwise with vigorous stirring, then stirred reaction mixture for 30min at room temperature to get your insocyanates. But the product itself is not stable. Mostly, this is intermediate for the synthesis of urea derivatives.

If you don't want to use triphosgene, simple add 2/3eq of diphosgene and follow the rest of procedure mentioned above.
If you have any question let me know