Stereochemistry of N -Acyl-5 H -dibenzo[ b , d ]azepin-7(6 H )-ones.

The stereochemical properties of N -acyl-5 H -dibenzo[ b , d ]azepin-7(6 H )-ones ( 2a - c ), which inhibit potassium channels in T cells, were examined by freezing their conformational change due to 4-methyl substitution. N -Acyl-5 H -dibenzo[ b , d ]azepin-7(6 H )-ones exist as pairs of enantiomers [(a 1 R , a 2 R ), (a 1 S , a 2 S )], and each atropisomer is separable at room temperature. An alternate procedure for preparing 5 H -dibenzo[ b , d ]azepin-7(6 H )-ones involves the intramolecular Friedel-Crafts cyclization of N -benzyloxycarbonylated biaryl amino acids. Consequently, the N -benzyloxy group was removed during the cyclization reaction to produce 5 H -dibenzo[ b , d ]azepin-7(6 H )-ones suitable for the subsequent N -acylation reaction.