Studies on organophosphorus compounds:: Synthesis and reactions of [1,2,4,3]triazaphospholo[4,5-a]quinoxaline derivative

2,4-Bis- (4-methoxyphenyl)-], 3,2,4dithiadiphosphetane-2,4-disulfide (Lawesson's reagent) (1) reacted with 2-hydrazino-3-methylquinoxaline (2) to give [1,2,4,3]-triazaphospholo[4,5alquinoxaline derivative 3. The Mannich reaction using different amines on compound 3 gave Mannich bases 4a-d. Also, compound 3 reacted with formaldehyde to give the corresponding 2-hydroxymethyl derivative 5, which upon reaction with thionyl chloride gave the corresponding chloromethyl derivative 6. Treatment of compound 6 with some thiols yielded the corresponding sulfides 7a-d. Acylation of compound 3 gave acylated compounds 8a,b. Compound 9, which was prepared through the reaction of compound 3 with ethyl cyanoacetate, was investigated as a starting material for the synthesis of some new heterocyclic systems 10-13. Also, reaction of compound 9 with carbon disulfide and 2 equivalents of methyl iodide in a one-pot reaction yielded the corresponding ketene-S,S-acetal 14, which in turn reacted with bidentates to give some new heterocycles 15-17. (D 2008 Wiley Periodicals, Inc.