Efficient Synthesis and Fungicidal Activities of 2-Alkylthiobenzofuro[3,2-d]Pyrimidinones

Abstract

2-Alkylthiobenzofuro[3,2-d]pyrimidinones 5 and 6 were synthesized by S-alkylation of 2,3-dihydro-2-thioxobenzofuro[3,2-d]pyrimidin-4(1H)-ones 4, which were obtained via aza-Wittig reaction of iminophosphorane 2 with CS₂ and further reaction of the product with various amines. Compounds 5 and 6 exhibited fungicidal activity. For example, compound 6a, which has a small N-substituted methyl group, showed the best inhibitive activity (91%) against Dothiorella gregaria at 50 mg/L.

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Keywords:

• Aza-Wittig reaction
• benzofuro[3,2-d]pyrimidinone
• carbon disulfide
• fungicidal activity
• iminophosphorane

Acknowledgments

We gratefully acknowledge financial support of this work by the Science Leader Plan of Wuhan City (No. 200750730312), National Natural Science Foundation of China (Project No. 20772041), and Key Project of Hubei Provincial Department of Education (No. D200724001).