Chemistry of the 1,3,5-triaza-2-phosphorin-4,6-diones .11. Base-catalyzed addition reactions of 2-oxo-2-hydro-1,3,5-trimethyl-1,3,5-triaza-2 lambda(4)-phosphorine-4,6-dione to the C=N double bond of 3-thiazoline heterocycles

The base-catalyzed reaction of 2-oxo-2-hydro-1,3,5-trimethyl-1,3,5-trimethyl-2 lambda(4)-phosphorine-4,6-dione (1) and of its trimethylsiloxy phosphorus(III) derivative (10) with various 3-thiazo-lines (2-5) via five different pathways is described. In all cases, the corresponding 3-thiazoline adducts were formed The different routes ars 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 H-1, C-13 and P-31 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.