Water → Phenyl cyanate

Participants

Reaction Steps

The title compound was prepared by a modification of the procedure described in Organic Syntheses, 61, 35 (1983). A 3-necked, 2L R. B. flask, equipped with a 500 ml pressure equalized dropping funnel, a mechanical stirrer and a thermometer, was charged with water and cooled in an ice-salt bath. Cyanogen bromide (189.1 g, 1.78 mol) was added and the mixture was stirred for 5 min. Phenol (160.0 g., 1.7 mol) in carbon tetrachloride (535 ml) was added in one portion. The mixture was stirred vigorously while triethylamine (236.9 ml, 172.0 g, 1.7 mol) was added dropwise at a rate such that the reaction temperature did not exceed 5° C. (total addition time=45 min.). The mixture was stirred for a further 15 min. then transferred to a 2L separatory funnel. The organic layer was separated and the aqueous layer was extracted with carbon tetrachloride (2×90 ml). The combined organic layers were washed with water (3×90 ml) then dried by stirring with phosphorus pentoxide (10 g) for 15 min. The mixture was filtered and the solvent was evaporated under reduced pressure (water aspirator) at 20° C. to give a yellow oil. Polyphosphate ester (Y. Kanaoka, et al., Chem. Pharm. Bull., 13, 1065-1072 (1965)) (0.2 ml) was added and the mixture was distilled under reduced pressure through a 15 cm vigreux column to give phenyl cyanate (165.8 g, 82%) as a colorless oil, b.p. 79°-82° C. (16 mmHg)1. The product was stored under nitrogen at -10° C. (freezes).

Provenance & Evidence