Abstract
2,4‐Bis‐(4‐methoxyphenyl)‐1,3,2,4‐dithiadiphosphetane‐2,4‐disulfide (Lawesson's reagent) (1) reacted with 2‐hydrazino‐3‐methyl‐quinoxaline (2) to give [1,2,4,3]‐triazaphospholo[4,5‐a]quinoxaline 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. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:520–529, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20473