Synthesis of cyanamides containing the phenothiazine fragment and their reactions with dialkyldithiophosphoric acids

Reaction of phenothiazine with dialkoxyphosphoryl or chlorosulfenyl isocyanide dichlorides has given 10-cyanophenothiazine, which adds dialkyldithiophosphoric acids at the CN bond. The addition products rearrange to 10-N-(dialkoxythiophosphoryl) thiocarbamoyl]phenothiazines, which are prone to decompose to dialkoxythiophosphoryl isothiocyanates and phenothiazine, or on treatment with alkyl halides in the presence of base afford stable S-alkyl-N- dialkoxythiophosphoryl (l0-phenothiazinyl)isothioformamides. The reaction between 10-cyanophenothiazine and an excess of dithiophosphoric acids also affords 10-thiocarbamoylphenothiazine and tetraalkyl trithiopyrophosphates. An x-ray diffraction examination of the molecular structure of S-methyl-N-diisopropoxythiophosphoryl-(10-phenothiazinyl)isothioformamide has shown it to possess the Z-configuration. The dihedral angle formed by the benzene rings of the phenothiazine fragment is 125.7°. The products of the addition of dithiophosphoric acids to the CN bond of N,N-bis2-(10-phenothiazinyl)-2-oxoethyl]cyanamide, obtained from 10-(chloroacety) phenothiazine and NaNHCN, also isomerize by 1,3S N migration of the thiophosphoryl group. Subsequent heterocyclization, with elimination of phenothiazine, affords 2-(dialkoxythiophosphorylimino)-3-2-(10-phenothiazinyl)-2-oxoethyl]thiazolidin-5-ones.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 451–460, February, 1991.