Crystal structure of seven-membered acetals with furan and pyridine planar fragments

Abstract

X-ray structure investigation of fused seven-membered acetals based on vitamin B6 and 3,4-bis(hydroximethyl)furan have been performed. Molecules adopt chair conformations with equatorial position of substituents at acetal carbons; the geometry of acetal cycles resembles that of related seven-membered phthalylacetals. Stereochemistry of the tetracyclic adduct of furan-containing acetal with maleic anhydride was also investigated. The product exhibits endo-exo configuration with appreciably distorted seven-membered chair-like conformation. © 2002 Elsevier Science B.V. All rights reserved.