Conformational analysis of hexahydro-3H-oxazolo[3,4-c]pyridines by carbon-13 fourier-transform nuclear magnetic resonance spectroscopy

Abstract

Comparison of the C(3), C(1), and C(8a) chemical shifts in hexahydro-3H-oxazolo[3,4-c]pyridine with those in anancomeric derivatives suggests its existence in solution at n.m.r. probe temperature as a cis⇌trans equilibrium mixture containing ca. 76% of the trans-fused conformation; ¹³C–H coupling constants involving the C(3) protons are dependent upon the orientation of adjacent lone pairs.