The destruction of N-nitrosamides with 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiodiphosphetane-2,4-disulfide. Attempts to nitrosate thioamides.

The reaction between N-nitrosamides and 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (LR) at low temperature (20-50 degrees C) gives the corresponding thioamides as the main products. In the reaction between N-nitroso-2-pyrrolidone and LR, dihydro-2-(3H)-thiophenone (III) is also isolated. Mechanistic considerations for the formation of III are presented. The nitrosation of thiono compounds gives the corresponding oxo analogues. N-Nitroso-2-pyrrolidone is obtained after nitrosation of 2-pyrrolidinethione. A kinetic investigation of this reaction has been performed using the theory of consecutive reactions with 2-pyrrolidone as an intermediate. The rate constants for these two reactions are found to be k1 = 0.055 s-1 for the formation of 2-pyrrolidone, using a first order plot of the change of 2-pyrrolidinethione; for the formation of N-nitroso-2-pyrrolidone, the rate constant obtained by computer simulation is k2 = 0.032 mol(-1)1 s-1.