Methyl 9-(4-methylbenzenesulfonyl)-4-phenyl-9 <i>H</i> -pyrido[3,4- <i>b</i> ]indole-3-carboxylate

The title β-carboline, C 26 H 20 N 2 O 4 S, which was synthesized via 2 + 2+2-cycloaddition to an alkynylynamide, is presented. There is one molecule in the asymmetric unit. The tricyclic carbolin framework is essentially planar and subtends an angle of 68.43 (19)° with the attached phenyl ring. In the crystal, the molecules are arranged in a zigzag pattern in the ac plane. Neighbouring molecules are connected via a twofold screw axis or a C 2 axis parallel to the b axis or via a center of inversion.