10-(Prop-2-yn-1-yl)-2,7-diaza­phenothia­zine

In the title mol­ecule [systematic name: 10-(prop-2-yn-1-yl)dipyrido[3,4-b:3′,4′-e][1,4]thia­zine], C₁₃H₉N₃S, the dihedral angle between the two pyridine rings is 146.33 (7)° and the angle between two halves of the thia­zine ring is 138.84 (8)°, resulting in a butterfly shape for the tricyclic system. The central thia­zine ring adopts a boat conformation, with the 2-propynyl substituent at the thia­zine N atom located in a pseudo-equatorial position and oriented to the concave side of the diaza­phenothia­zine system. In the crystal, mol­ecules are arranged via π–π inter­actions between the pyridine rings [centroid–centroid distances = 3.838 (1) and 3.845 (1) Å] into stacks extending along [001]. There are C—H...C and C—H...N inter­actions between mol­ecules of neighbouring stacks.

N-[4-(9-Chloro­quino[3,2-b]benzo[1,4]thia­zin-6-yl)but­yl]acetamide

In the title mol­ecule, C₂₁H₂₀ClN₃OS, the tetra­cyclic system is close to planar [r.m.s. deviation = 0.110 (4) Å]. The dihedral angle between the quinoline ring system and the benzene ring is 178.3 (1)° and the angle between two (S—C=C—N) halves of the thia­zine ring is 173.4 (1)°. In the crystal, mol­ecules are arranged via π–π inter­actions [centroid–centroid distances = 3.603 (2)–3.739 (2) Å] into slipped stacks extending along [010]. Inter­molecular N—H...O hydrogen bonds link the amide groups of neighbouring mol­ecules along the stack, generating a C(4) motif. The title compound shows promising anti­proliferative and anti­cancer activity.