Cyclic organophosphorus compounds. Part 6. Synthesis of N-methyl-2-phenoxy-1,3,2-oxazaphosphorinan-2-thione and its crystal and molecular structures

Abstract

2-Chloro-1,3,2-oxazaphosphorinan-2-thione (1) was prepared by treatment of phosphorothioic trichloride with 3-aminopropan-1-ol in the presence of triethylamine. Treatment of (1) with sodium phenoxide afforded the 2-phenoxy-derivative (2) from which the title compound (3) could be obtained by the action of sodium hydride followed by alkylation with an excess of methyl iodide. The structure of the title compound has been determined by the direct method and refined by least-squares to R= 0.037 2, a= 7.240(3), b= 10.705(4), c= 15.327(4)Å, β= 91.475(5)°, space group P2₁/n. The oxazaphosphorinan ring is in the chair form with the PS bond in the equatorial position.