Synthesis and structure of O,O-diethyl N-[(trans-4-aryl-5,5-dimethyl-2-oxido-2λ5-1,3,2-dioxaphosphorinan-2-yl)methyl]phosphoramidothioates

A study on the synthesis of the novel N-(cyclic phosphonate)-substituted phosphoramidothioates, i.e.. O,O-diethyl N-[(trans-4-aryl-5,5-dimethyl-2-oxido-2 lambda(5)-1,3,2-dioxaphosphorinan-2-yl)methyl]phosphoramidothioates 4a-1. from O,O-diethyl phosphoramidothioate (1), a benzaldehyde or ketone 2, and a 1.3.2-dioxaphosphorinane 2-oxide 3 was carried out (Scheme 1 and Table 1). Some of their stereoisomers were isolated, and their structure was established. The presence of acetyl chloride was essential for this reaction and accelerated the process of intramolecular dehydration of intermediate 5 forming the corresponding Schiff base 7 (Scheme 2).