3729-19-9

Usage

Preparation

Diphosgene is toxic. The reaction should be carried out in a well-ventilated hood. A 500-mL, twonecked flask was equipped with a thermometer and a reflux condenser protected at the top by a calcium chloride guard tube. A Teflon-coated magnetic stirring bar, anhydrous dioxane (250 mL), finely pulverized 3-aminopropanoic acid hydrochloride 1342 (b-alanine HCl) (12.6 g, 0.1 mol), and diphosgene (23.8 g, 14.4 mL, 0.12 mol) were placed in the flask in the order specified. The mixture was stirred and heated at 55–60 C°. After ca. 5 h, the solid had completely dissolved to give a clear solution. Heating was discontinued after a total of 7 h and the solvent was removed under reduced pressure. The residual oil was rapidly distilled under reduced pressure and a distillate amounting to 11.2–12.4 g (84–93%) was collected at 75–85 C°/20 mmHg. Redistillation afforded 10.5–11.8 g (79–88%) of 3-isocyanatopropanoyl chloride 1343 as a colorless liquid (bp 92–94 C°/25 mmHg). Comment: Although the reaction can be carried out with an equimolar amount of trichloromethyl chloroformate, a longer time (15–20 h) is required to reach completion, and the yield is somewhat reduced. If a 1.5–2.0-fold excess of trichloromethyl chloro-formate is used, the reaction time is decreased to ca. 5 h and the yield is increased to 90–95%. Organic acid chlorides have been prepared with diphosgene in the presence of DMF as a catalyst.

Upstream product

• 75-44-5 phosgene 
• 4244-84-2 ethyl β-alaninate hydrochloride 
• 3196-73-4 methyl 3-aminopropanoate hydrochloride 
• 107-95-9 3-amino propanoic acid 
• 6057-90-5 β-alanine hydrochloride 
• 503-38-8 trichloromethyl chloroformate 
• 27762-02-3 N-Silyloxycarbonyl-β-alanin-trimethylsilylester 

Downstream Products

• 5100-12-9 3-<3-(4-Aethoxy-phenyl)-ureido>-propionsaeure-p-phenetidid 
• 75-77-4 chloro-trimethyl-silane 
• 115345-78-3 3-Isocyanato-propionic acid phenyl ester 
• 114503-07-0 3-Isocyanato-propionic acid 4-(3-isocyanato-propionyloxy)-butyl ester 

Relevant academic research and scientific papers

Organosilicon synthesis of isocyanates: III. Synthesis of aliphatic, carbocyclic, aromatic, and alkylaromatic isocyanatocatboxylic acid esters

A series of aminoacid esters was prepared by treating the aminoacid suspensions in ethanol with thionyl chloride. Best conversion of aminoacid esters to corresponding isocyanates was achieved in the case of aromatic and carbocyclic aminoesters by phosgeneation of their N-silyl derivatives, and in the case of aliphatic and alkylaromatic aminoesters by phosgeneation of O-silyl or N,O-bissilylurethanes on their basis. In the last case additional step of esterification of the by-products isocyanatoalkylcarboxylic acid chlorides is required after phosgeneation. Unusual generation of cynnamates and intramolecular N→O-migration of trimethylsilyl group in the solutions of silylated alkylaromatic β-aminoacid esters were found. Pleiades Publishing, Inc., 2006.

Synthesis and Stabilisation of Isocyanatoketenes

The isocyanatocarbonyl chlorides 1a-m were prepared and converted to the corresponding isocyanatoketenes 2a-m by means of hydrogen chloride elimination with triethylamine. (Isocyanatoalkyl)ketenes with less then three carbon atoms between the functional groups yield crosslinked and oligomeric products, respectively, by intermolecular reaction of the different heterocumulene systems. (ω-Isocyanatoalkyl)aldoketenes with three and more carbon atoms between the functional groups (2d-h) stabilize uniformly by -cycloaddition of the ketene groups to yield 3-(ω-isocyanatoalkyl)-4-(ω-isocyanatoalkylidene)-2-oxetanones (3d-h) (diisocyanatodiketenes). (4-Isocyanatophenyl)ketene (2l) and (3-isocyanato-1,5-pentanediyl)ketene (2k) stabilize in analogy to the unsubstituted parent compounds to give 6l and 4k, respectively.