Chemistry of the 1,3,5-Triaza-2-phosphorin-4,6-diones, Part XI*. Base-Catalyzed Addition Reactions of 2-Oxo-2-hydro-1,3,5-trimethyl-1,3,5-triaza-2λ4-phosphorine-4,6-dione to the C=N Double Bond of 3-Thiazoline Heterocycles

Abstract

The base-catalyzed reaction of 2-oxo-2-hydro-1,3,5-trimethyl-1,3,5-triaza-2λ4-phosphorine- 4,6-dione (1) and of its trimethylsiloxy phosphorus(III) derivative (10) with various 3-thiazolines (2 -5 ) via five different pathways is described. In all cases, the corresponding 3-thiazoline adducts were formed. The different routes are compared with regard to reaction conditions and yields. In the reaction of 1 with 5,5-dimethyl-2-isopropyl-3-thiazoline (3) two diastereomers of 7 were formed, as established by 1H , 13C and 31P NMR spectroscopy. The structures of the products 6 and 8 were confirmed by X-ray analysis; the thiazolidine rings display a twist conformation through the sulfur atom. The molecules are linked via inversion centres by hydrogen bonds of the form N-H···O= C.