Chemical Properties
clear colourless liquid
Uses
Vinyl Chloroformate was used to prepare analogues of the Nicotinic Acetylcholine Receptor Agonist (±)-UB-165. It was also used to synthesize possible antitumor agents such as paclitaxel-2''-carbonates and N-carbamyl triazenes.
Synthesis
Two processes have been used commercially to make Vinyl Chloroformate. First, ethylene glycol is converted to its bis(chloroformate) with phosgene. This fragments to VOC-Cl in 30- 40% yield when passed through a hot tube packed with glass helices at 480 °C. More recently, VOC-Cl has been made commercially using a two-step route involving the oxymercuration of vinyl acetate.
Purification Methods
It has been fractionated through a Todd column (p 11, Model A with ~60 plates) under atmospheric pressure and the purity can be checked by gas chromatography. Stabilize it with 0.5% of 2,6-di-tert-butyl-p-cresol. It has IR with at 3100 + 2870 (CH2), 1780 (C=O), 1640 (C=C) and 940 (CH2out-of-plane) and 910 (CH2 wagging) cm-1. [IR: Lee J Org Chem 30 3943 1965, Levaillant Ann Chim (Paris) 6 504 1936.] It is used for protecting NH2 groups in peptide synthesis [Olofson et al. Tetrahedron Lett 1563 1977]. [Beilstein 3 III 28.]
Precautions
Vinyl Chloroformate is slightly light-sensitive and more reactive than other chloroformates toward trace moisture. Because hydrolysis products, HCl and acetaldehyde, interfere with some applications, the reagent is often distilled before use. It is a strong lachrymator and skin vesicant; inhalation is hazardous. Use in a fume hood.
