Facile Synthesis of 2-Alkylthio-5,6,7,8-tetrahydrobenzothieno[2,3-d]pyrimidin-4(3H)-ones

Abstract

Isothiocyanate 2, obtained from aza-Wittig reaction of iminophosphorane 1 with CS₂, reacted with amine to give 2-thioxo-2,3,5,6,7,8-hexahydrobenzothieno[2,3-d]pyrimidin-4(1H)-ones 4 in the presence of sodium ethoxide. S-Alkylation of 4 produced 2-alkylthio-5,6,7,8-tetrahydrobenzothieno[2,3-d]pyrimidin-4(3H)-ones 5 in good yields.

Keywords:

• Aza-Wittig reaction
• carbon disulfide
• iminophosphorane
• isothiocyanate
• thieno[2,3-d]pyrimidin-4(3H)-one

ACKNOWLEDGMENTS

We gratefully acknowledge financial support of this work by the National Natural Science Foundation of China (Project No. 20772041), the Key Project of Chinese Ministry of Education (No. 107082), and the Educational Commission of Hubei Province of China (No. B20092412).