Stereochemical studies. 58. Saturated heterocycles. 39. Preparation and steric structures of dihydro‐1,3‐oxazines, 1,3‐oxazin‐2‐ones and 1,3‐oxazine‐2‐thiones fused with norbornane and norbornene

Publisher Website
Google Scholar
Abstract
3‐endo‐Aminobicyclo[2.2.1]hept‐5‐ene‐2‐endo‐carboxylic acid (1), prepared from endo‐norborn‐5‐ene‐2,3‐dicarboxylic acid anhydride, and the analogous saturated cis‐exo‐amino acid (3) were reduced with lithium aluminum hydride to the aminoalcohols 2 and 4; the latter were cyclized by means of arylimino ethers to methylene‐bridged tetrahydro‐ (6a‐c) and hexahydro‐3,1‐benzoxazines (7b‐d), respectively. The endo (2) and exo (4) aminoalcohols were converted to methylene‐bridged tetrahydro‐3,1‐benzoxazin‐2‐one (9) and hexahydro‐3,1‐benzoxazin‐2‐one (12) with ethyl chloroformate and sodium methoxide; treatment of the alcohols with carbon disulfide gave, via the dithiocarbamates, the corresponding 2‐thiones (11, 13). The structures were confirmed by ir and nmr spectroscopy.