Studies of Substituent Effect in the Formation of Benzonitrile Oxides and 1, 3-Dipolar Adducts of the Benzonitrile Oxides with 2, 3, 4, 6-Tetra-O-acetyl-1-thio-β-D-glucopyranose

Abstract

Coupling reagents were prepared from corresponding benzaldehyde oximes by successive treatment with chlorine and Et₃N; the products were used without purification because of their instability. The reactions of 2, 3, 4, 6-tetra-O-acetyl-1-thio-β-D-glucopyranose (1) with the coupling reagents obtained from benzaldehyde oxime (2a) and phenylacet-aldehyde oxime (2b) gave normal 1, 3-dipolar addition products (3a and 3b, respectively) in good yields. The reactions of 1 with the coupling reagents obtained from p- (2c), m- (2d), and o-methoxybenzaldehyde oxime (2e) gave the 1, 3-addition products chlorinated on the benzene ring; 3c and 3d from 2c, 3e and 3f from 2d, and 3g from 2e. On the other hand, the reactions of 1 with the coupling reagents obtained from p-chloro- (2f) and p-nitrobenzaldehyde oxime (2g) gave no 1, 3-addition product.