Synthesis and Fungicidal Activity of 12-Alkoxyiminothiopentadecanlactones

GRAPHICAL ABSTRACT

Abstract

A series of novel 12-alkoxyiminothiopentadecanlactones were synthesized starting from 2-nitrocyclododecanone by Michael addition to acrolein, followed by selective reduction of the aldehyde group, conversion of hydroxyl group to mercapto group, ring expansion, Nef reaction, and finally reaction with alkoxyamines. Their structures were confirmed by ¹H NMR, ¹³C NMR spectra, and mass spectrometry. The Z and E isomers of some of the title compounds were separated by column chromatography and their configurations were determined by ¹H NMR. These compounds showed excellent fungicidal activity against P. asparagi and are better than the commercial fungicide chlorothalonil. The results indicated that replacing an oxygen atom or NH group by sulfur atom may be an effective approach to improve the fungicidal activity or change the fungicidal spectrum of macrolactones and macrolactams.

Keywords:

• Synthesis
• 12-nitro-1,15-thiopentadecanlactone
• 12-oxo-1,15-thiopenta- decanlactone
• 12-alkoxyimino-1,15-thiopentadecanlactone
• fungicidal activity