Synthesis of 1,3,5-thiadiazines from formamidinothiocarbamide

: Novel series of 2-suhstitutedamino-4-(2-imino-4-thiobiureto-S-yl-carbamidino)-6-substitutedimino-1,3,5-thiadiazines (3a-f) and 2-substitutedamino-4-(4-imino-6-substitutedimino-1,3,5-thiadiaz-2-yl)-6-substitutedimino-1,3,5-thiadiazines (Sa-f) has been obtained by basification of their hydrochlorides (la-O and (4a-f) respectively. The latter were synthesized by the interaction of 1-formamidino-3-thioamido-N-substitutedformamidinothiocarbamides (la-O and N substitutedisocyanodichloride in 1 : 1 and 1 : 2 molar ratio respectively which were prepared initially by the condensa tion of aryllalkylisothiocyanate and 1,3-diformamidinothiocarhamide in 1 : 1 molar ratio. The structure of all these compounds were established on the basis of elemental analysis, IR and PMR spectral data. formamidino-3-thioamido-N-substitutedformamidinothio carbamides in l : l and l : 2 molar ratios.

The literature survey revels that the heterocyclic compounds having l ,3,5-thiadiazines nucleus enhanced pharmaceutical, medicinal, agricultural and industrial values 1 . The synthetic applications of N-substitutedisocyanodichlorides have been investigated and shown to have enough potential in the synthesis of nitrogen and sulphur containing heterocyclic compounds 2 thus aim to synthesized l ,3,5-thiadiazines, reaction of N-aryl/alkylisocyanodichloride have been carried out with different Iformamidino-3-thioamido-N-substitutedformamidinothiocarbamides in l : l and l : 2 molar ratios.

Experimental
All chemicals used were of analar grade. N-Substitutedisocyanodichlorides were prepared according to literature method 3 . Melting point of all synthesized compounds was determined in open capillary and uncorrected; IR spectra were recorded on Perkin-Elmer spectrometer in the range 4000-400 cm-1 in Nujol mull as KBr pellets. PMR spectra were recorded with TMS as internal standard using CDCI 3 and DMSO-d 6 . TLC checked the purity of the compounds on silica gel-G plates with layer thickness of 0.3 mm. All compounds gave satisfactory C, H, Nand S elemental analysis.
The parent compound l-formamidino-3-thioamido-Nsubstitutedformamidinothiocarbamide (la-t) was prepared by refluxing the mixture of l ,3-diformamidinothiocarbamide with aryl/alkylisothiocyanate in 1 : 1 molar ratio in acetone ethanol medium for 4 h on water bath.
Similarly, other compounds (lb-t) were synthesized and enlisted in Table 1.
Similarly, other compounds, (4a(ii) to 4f(iv)) were synthesized from (la-f). And which on basification yielded other thiadiazines (Sa(ii) to Sa(iv)) and (Sb(ii) to Sf(iv)) by above mention method and enlisted in Table 2.