General approach for regioselective synthesis of fused phosphono substituted-oxadiazines

Abstract

A series of fused 1,3,4‐oxadiazines were regioselectively prepared in reasonable yields as major products from the reactions of the corresponding α‐carbonyl hydrazones with tetraethyl 1,3‐dithietane‐2,4‐diylidene‐bis(cyanomethylphosphonate) (1). Side products were also observed wherein the dimeric products 8 or 17 and/or different types of N‐heterocycles such as pyrazole 24 or pyridazines 28 or 29 were isolated and identified. A comparative study on the chemistry of 1 toward α‐aminonitrile 30 is also described. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:196–204, 2000