PYROTHIOCARBONATES I. AMINOLYSIS OF S-(ETHOXYCARBONYL) O-ETHYL DITHIOCARBONATE

Abstract

The reaction of S-(ethoxycarbonyl) O-ethyl dithiocarbonate (1) with equimolar amounts of butylamine, benzylamine, diethylamine and piperidine in ethanol solution at 0°C is reported. The mole ratio of O-ethyl thiocarbamate (2) and O-ethyl carbamate (3) formed as main products is larger than unity during all the reaction. Bis(ethoxythiocarbonyl) sulfide (4) and bis(ethoxycarbonyl) sulfide (5) are also produced and their formation is explained in terms of the reaction of 1 with EtOCS₂ ⁻ and EtOCOS⁻, respectively, which are the leaving groups in the aminolysis of 1. Reactions 4 → 2 and 5 → 3 also take place. When 50% of 1 has been consumed compound 4 is not detected and compound 5 is found at very low concentration, indicating that generation of 4 and 5 occurs mainly after aminolysis of 1. The fact that the ratio of 2:3 is larger than unity in this aminolysis step, and that S-methyl O-ethyldithiocarbonate is aminolyzed more readily than S-methyl O-ethylmonothiocarbonate under the same conditions as the aminolysis of 1, suggests that the thiocarbonyl group of 1 is more reactive than the carbonyl group.