The synthesis, crystal structure and Hirshfeld surface analysis of the thio-phene derivatives 5-(phenyl-sulfon-yl)-5,6-di-hydro-benzo[4,5]thieno[3,2-j]phenanthridine and (E)-N-{2-[2-(benzo[b]thiophen-2-yl)ethenyl]phen-yl}-N-(prop-2-yn-1-yl)benzene-sulfonamide

The crystal structures and Hirshfeld surface analysis of three new bromo-substituted 3-methyl-1-(phenyl-sulfon-yl)-1H-indole derivatives

Three new 1H-indole derivatives, namely, 2-(bromo-meth-yl)-3-methyl-1-(phenyl-sulfon-yl)-1H-indole, C16H14BrNO2S, (I), 2-[(E)-2-(2-bromo-5-meth-oxy-phen-yl)ethen-yl]-3-methyl-1-(phenyl-sulfon-yl)-1H-indole, C24H20BrNO3S, (II), and 2-[(E)-2-(2-bromo-phen-yl)ethen-yl]-3-methyl-1-(phenyl-sulfon-yl)-1H-indole, C23H18BrNO2S, (III), exhibit nearly orthogonal orientations of their indole ring systems and sulfonyl-bound phenyl rings. Such conformations are favourable for inter-molecular bonding involving sets of slipped π-π inter-actions between the indole systems and mutual C-H⋯π hydrogen bonds, with the generation of two-dimensional monoperiodic patterns. The latter are found in all three structures, in the form of supra-molecular columns with every pair of successive mol-ecules related by inversion. The crystal packing of the compounds is additionally stabilized by weaker slipped π-π inter-actions between the outer phenyl rings (in II and III) and by weak C-H⋯O, C-H⋯Br and C-H⋯π hydrogen bonds. The structural significance of the different kinds of inter-actions agree with the results of a Hirshfeld surface analysis and the calculated inter-action energies. In particular, the largest inter-action energies (up to -60.8 kJ mol-1) are associated with pairing of anti-parallel indole systems, while the energetics of weak hydrogen bonds and phenyl π-π inter-actions are comparable and account for 13-34 kJ mol-1.

Synthesis of Cytotoxic Quino[4,3-b]carbazole Frameworks through an Intramolecular Diels-Alder Reaction

An intramolecular Diels-Alder reaction of positionally isomeric indole-2/3-phenylvinyl-N-alkynylated (N-phenylsulfonyl)amines has been successfully exploited for the synthesis of quino[4,3-b]carbazole and its analogues. This reaction proceeds through a [4 + 2] cycloaddition followed by elimination and deprotection of phenylsulfonyl units to afford the quinocarbazoles in moderate to good yields. The reaction features a broad substrate scope and remarkable functional group forbearance. A preliminary in vitro cytotoxicity evaluation of representative quino[4,3-b]carbazoles was performed against NCI-H460 human cancer cell culture. Among the quino[4,3-b]carbazoles evaluated, five of the fluorine-containing quinocarbazoles displayed nano molar range (0.8-2.0 nm) GI50 values. The UV-vis and fluorescence spectral studies of representative quinocarbazoles were also performed. Like ellipticine, four of the quinocarbazoles displayed dual emissions confirming the existence of p-quinonoid like tautomeric forms in a polar protic solvent.

Crystal-structure determination and Hirshfeld surface analysis of two new thio-phene derivatives: (E)-N-{2-[2-(benzo[b]thio-phen-2-yl)ethen-yl]-5-fluoro-phen-yl}benzene-sulfonamide and (E)-N-{2-[2-(benzo[b]thio-phen-2-yl)ethen-yl]-5-fluoro-phen-yl}-N-(but-2-yn-1-yl)benzene-sulfonamide

In the title compounds, C22H16FNO2S2 (I) and C26H20FNO2S2 (II), the benzo-thio-phene rings are essentially planar with maximum deviations of 0.009 (1) and 0.001 (1) Å for the carbon and sulfur atom in compounds I and II, respectively. In I, the thio-phene ring system is almost orthogonal to the phenyl ring attached to the sulfonyl group, with a dihedral angle of 77.7 (1)°. In compound I, the mol-ecular structure is stabilized by weak C-H⋯O intra-molecular inter-actions formed by the sulfone oxygen atoms, which generate two S(5) ring motifs. In the crystal of I, N-H⋯O hydrogen bonds link the mol-ecules into R 2 2(8) rings, which are connected into a C(10) chain via C-H⋯F hydrogen bonds. Inter-molecular C-H⋯π inter-actions are also observed. In compound II, the mol-ecules are linked via C-H⋯O and C-H⋯F hydrogen bonding, generating infinite C(11) and C(13) chains running parallel to [010].