Synthesis of Atropisomeric Benzoxazocines Based on Etherification Products of N-[2-(Cycloalk-1-en-1-yl)-phenyl]sulfonamides with Ethylene Chlorohydrin.

The reactions of N-[2-(cyclohex-1-en-1-yl)-6-methylphenyl]arenesulfonamides and N-[2-(cyclohex-1-en-1-yl)phenyl]methanesulfonamide with molecular bromine in the presence of ethylene chlorohydrin afforded mixtures of N-{2-[6-(2-chloroethoxy)cyclohex-1-en-1-yl]phenyl} sulfonamides and 9-(arenesulfonyl)- or 9-(methanesulfonyl)-2,3,9,9a-tetrahydro-1H-carbazoles. Intramolecular condensation of the obtained 2-chloro-ethyl ethers in the presence of potassium hydroxide and benzyl(triethyl)ammonium bromide in THF gave 8-(arenesulfonyl)-9-methyl-2,4,4a,6,7,8-hexahydro-3H-dibenzo[e,g][1,4]oxazocines as a result of forma-tion of new nitrogen–carbon bond. The presence of a methyl group at C9 of the aromatic ring gives rise to axial isomerism of the synthesized benzoxazocines. The major conformer of the cyclocondensation products has aS*,R* configuration of the heterocycle, and this conformer slowly isomerizes to the aR*,R* conformer at room temperature. [ABSTRACT FROM AUTHOR]