A NOVEL SYNTHESIS OF SPIRO 1,3-DITHIIN AND SPIRO 1,3-THIAZINE DERIVATIVES UNDER PHASE TRANSFER CATALYSIS (PTC) CONDITIONS

Abstract

Ketene S,S-acetals 1a, b or ketene N,S-acetals 2a, b reacts in situ with a variety of ylidenemalononitriles to afford the desired spiro [1,3]dithiin heterocycles 3a, b–11a, b or spiro[1,3]thiazine heterocycles 12a, b–20a, b. Treatment of 2-(1-acetyl-2-oxopropylidene)spiro[1,3]thiazine derivatives 13b, 17d, and 18d with malononitrile afforded the corresponding dispiro heterocycles 21, 22, and 23.

Keywords:

• Dispiro heterocycles
• ketene acetals
• spiro-1,3-dithiin
• spiro-1,3-thiazine

The author wishes to thank Dr. Jerzy Suwinski and Mr. Mounir Abbas, Institute of Organic Chemistry and Technology, Silesian Technical University, 44-100 Gliwice, Poland, for the empirical calculation.

Notes

^a Uncorrected.

^b Satisfactory microanalysis obtained C; +0.35, H; +0.4, N; +0.2.

^c Measured on a Nicolet 710 FT-IR spectrometer.

^d Measured by a Varian EM 360L spectrometer at 60 MHZ using TMS as internal standard and DMSO d₆ as a solvent.