(2Z)-2-Benzyl-idene-4-(prop-2-yn-1-yl)-2H-1,4-benzo-thia-zin-3(4H)-one.

The mol-ecule of the title compound, C18H13NOS, is build up from two fused six-membered rings, with the heterocyclic component linked to a benzyl-idene group and to a prop-2-yn-1-yl chain. The six-membered heterocycle adopts a distorted screw-boat conformation. The prop-2-yn-1-yl chain is almost perpendicular to the mean plane through benzo-thia-zine as indicated by the C-N-C-C torsion angle of 86.5 (2)°. The dihedral angle between the benzene rings is 47.53 (12)°. There are no specific inter-molecular inter-actions in the crystal packing.

4-(Prop-2-yn-yl)-2H-1,4-benzo-thia-zin-3(4H)-one.

In the title compound, C11H9NOS, the six-membered heterocycle of the benzo-thia-zine fragment exhibits a screw-boat conformation. The benzene ring makes a dihedral angle of 79.4 (1)° with the mean plane through the prop-2-ynyl chain and the ring N atom. In the crystal, mol-ecules are linked by C-H⋯O inter-actions of the acetyl-enic C-H group towards the carbonyl O atom of a neighbouring mol-ecule, forming zigzag chains running along the b-axis direction.

Ethyl 2-{5-[(3-oxo-3,4-di-hydro-2H-1,4-benzo-thia-zin-4-yl)meth-yl]-1H-1,2,3-triazol-1-yl}acetate.

In the title compound, C15H16N4O3S, the six-membered heterocycle of the benzo-thia-zine fragment exhibits a screw boat conformation. The dihedral angle between the planes through the triazole ring and the benzene ring fused to the 1,4-thia-zine ring is 62.98 (11)°. The mean plane formed by the atoms belonging to the acetate group is nearly perpendicular to the triazole ring [dihedral angle = 74.65 (12)°]. In the crystal, mol-ecules are linked by pairs of C-H⋯O inter-actions, forming dimeric aggregates.

4-[(1-Benzyl-1H-1,2,3-triazol-4-yl)meth-yl]-2H-1,4-benzo-thia-zin-3(4H)-one.

In the title compound, C18H16N4OS, the six-membered heterocycle of the benzo-thia-zine fragment exhibits a screw-boat conformation. The dihedral angles between the plane through the triazole ring and those through the fused and terminal benzene rings are 76.68 (11) and 71.0 (1)°, respectively; the benzene rings are nearly perpendicular [dihedral angle = 79.6 (1)°]. In the crystal, mol-ecules are linked by C-H⋯N and C-H⋯O inter-actions, forming a three-dimensional network.

4-(1,3-Benzothia-zol-2-yl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one.

The central five-membered ring of the title compound, C(18)H(15)N(3)OS, is almost planar (r.m.s. deviation = 0.028 Å) and the benzothia-zole fused-ring system is close to coplanar with this ring [dihedral angle = 6.1 (1)°]. The phenyl substituent is twisted by 62.5 (1)°.

(E)-4-(2,3-Dihydro-1,3-benzothia-zol-2-yl-idene)-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one.

In the title compound, C(17)H(13)N(3)OS, the dihedral angle between the ring systems is 2.22 (5)°. The N-H grouping participates in both intra- and intermolecular N-H⋯O hydrogen bonds, the latter leading to dimers related by a twofold rotation axis.

1-(1-Nonyl-2-oxoindolin-3-yl-idene)thio-semicarbazide.

In the title compound, C(18)H(26)N(4)OS, the imine C=N bond has a Z configuration, whereas the N-N-C=S unit has an E conformation. In the crystal, mol-ecules are connected through N-H⋯O hydrogen bonds, forming zigzag chains running along the b axis. The nonyl chain adopts an extended zigzag conformation.

1-(1-Decyl-2-oxoindolin-3-yl-idene)thio-semicarbazide.

In the title 1-alkyl-isatin 3-thio-semicarbazone, C(19)H(28)N(4)OS, the imine C=N bond has a Z configuration, whereas the N-N-C=S unit has an E conformation. In the crystal, mol-ecules are connected by N-H⋯O hydrogen bonds, forming zigzag chains running along the b axis.

3-(Benzothia-zol-2-yl)-3-(prop-2-yn-yl)hex-5-yn-2-one.

The title compound, C(16)H(13)NOS, was prepared by alkyl-ation of 1-(benzothia-zol-2-yl)propan-2-one with propargyl bromide. The asymmetric unit contains two mol-ecules that are crystallographically independent but linked to each other by non-classical C-H⋯O hydrogen bonds, building up a dimeric substructure. The benzothia-zole rings are essentially planar with maximum deviations of 0.005 (1) and 0.007 (2) Šfor the N atoms. Although the two mol-ecules have similar bond distances and angles, they slightly differ in the orientation of the benzothia-zole ring with respect to the two propargyl groups and the acetonyl unit . In the crystal, inter-molecular C-H⋯O inter-actions link the dimeric subunits into a two-dimensional array in the bc plane.

1-Allyl-4-(1,3-benzothia-zol-2-yl)-5-methyl-2-phenyl-1H-pyrazol-3(2H)-one.

The title compound, C(20)H(17)N(3)OS, is a 1H-pyrazol-3(2H)-one having aromatic 4-(1,3-benzothia-zol-2-yl)- and 2-phenyl substituents. The five-membered ring and fused ring system are planar, the r.m.s. deviations being 0.021 and 0.005 Å, respectively. The five-membered ring is aligned at 7.9 (2)° with respect to the fused-ring system. The allyl and phenyl parts of the mol-ecule are both disordered over two positions in a 1:1 ratio. Weak inter-molecular C-H⋯O hydrogen bonding is present in the crystal structure.

4-(1,3-Benzothia-zol-2-yl)-5-methyl-2-phenyl-1-propynyl-1H-pyrazol-3(2H)-one.

The title compound, C(20)H(15)N(3)OS, is a 1H-pyrazol-3(2H)-one having aromatic 4-(1,3-benzothia-zol-2-yl) and 2-phenyl substit-uents. The five-membered ring and the fused-ring system are close to planar, the r.m.s. deviations being 0.025 and 0.005 Å, respectively. The five-membered ring is aligned at 67.5 (1)° with respect to the phenyl ring and at 4.7 (1)° with respect to the fused-ring system. In the crystal, adjacent mol-ecules are linked through the acetyl-enic H atom by a C-H⋯O hydrogen bond into C(8) chains propagating in [010].