Prodn. of 1-thio:phosphoryl-3-cyano-thiourea alkali metal and ammonium salts - comprises reaction of thio:phosphoryl isothiocyanate with cyanamide or alkali metal salt

摘要

Prodn. of 1-dialkoxythio phosphoryl -3-cyanothiourea alkali metal and trialkylammonium salts (I) comprises reacting a dialkoxythiophosphoryl isothiocyanate (II) in a solvent either with an alkali metal cyanamide (IIIa) or with cyanamide in the presence of a trialkylamine (IV). R = alkyl or aryl; R' = alkyl; M+ = alkali metal cation. USE/ADVANTAGE - Cpds. (I) are intermediates for biocides and pharmaceuticals. The method is more selective than the processes using alkyamimes and arylamines (US4269829, US4276290, US4137310, US2708863, J75132131 and J7493541). Yields are e.g. 50-90%. In an example, a soln. of diethoxythiophosphoryl isothiocyanate (II) (21.1 g) in acetonitrile (100 ml) was added dropwise to sodium cyanamide (IIIa) (6.4 g) in acetonitrile (300 ml) and the mixt. was stirred, evaporated, cooled to -20 deg.C and treated with ether to give 1-diethoxythio phosphoryl -3-cyanothiourea sodium salt (I); m.pt. 130 deg.C; yield 50%.