Crystal structures of (Z)-5-[2-(benzo[b]thio-phen-2-yl)-1-(3,5-di-meth-oxy-phen-yl)ethen-yl]-1H-tetra-zole and (Z)-5-[2-(benzo[b]thio-phen-3-yl)-1-(3,4,5-tri-meth-oxy-phen-yl)ethen-yl]-1H-tetra-zole.

Narsimha Reddy Penthala,Sean Parkin,Jaishankar K B Yadlapalli,Peter A Crooks

doi:10.1107/s2056989016005600

Abstract

(Z)-5-[2-(Benzo[b]thio-phen-2-yl)-1-(3,5-di-meth-oxy-phen-yl)ethen-yl]-1H-tetrazole methanol monosolvate, C19H16N4O2S·CH3OH, (I), was prepared by the reaction of (Z)-3-(benzo[b]thio-phen-2-yl)-2-(3,5-di-meth-oxy-phen-yl)acrylo-nitrile with tri-butyl-tin azide via a [3+2]cyclo-addition azide condensation reaction. The structurally related compound (Z)-5-[2-(benzo[b]thio-phen-3-yl)-1-(3,4,5-tri-meth-oxy-phen-yl)ethen-yl]-1H-tetra-zole, C20H18N4O3S, (II), was prepared by the reaction of (Z)-3-(benzo[b]thio-phen-3-yl)-2-(3,4,5-tri-meth-oxy-phen-yl)acrylo-nitrile with tri-butyl-tin azide. Crystals of (I) have two mol-ecules in the asymmetric unit (Z' = 2), whereas crystals of (II) have Z' = 1. The benzo-thio-phene rings in (I) and (II) are almost planar, with r.m.s deviations from the mean plane of 0.0084 and 0.0037 Å in (I) and 0.0084 Å in (II). The tetra-zole rings of (I) and (II) make dihedral angles with the mean planes of the benzo-thio-phene rings of 88.81 (13) and 88.92 (13)° in (I), and 60.94 (6)° in (II). The di-meth-oxy-phenyl and tri-meth-oxy-phenyl rings make dihedral angles with the benzo-thio-phene rings of 23.91 (8) and 24.99 (8)° in (I) and 84.47 (3)° in (II). In both structures, mol-ecules are linked into hydrogen-bonded chains. In (I), these chains involve both tetra-zole and methanol, and are parallel to the b axis. In (II), mol-ecules are linked into chains parallel to the a axis by N-H⋯N hydrogen bonds between adjacent tetra-zole rings.

Highlights

In both structures, molecules are linked into hydrogen-bonded chains
In (II), molecules are linked into chains parallel to the a axis by N—H N
0.0084 Å in (II), with bond distances and angles comparable with those reported for other benzothiophene derivatives (Sonar et al, 2007; Penthala et al, 2014b)

Summary

Chemical context

A-4 analogs (Penthala et al, 2013), and benzothiophene triazolylcombretastatin A-4 analogs as promising anti-cancer agents (Penthala et al, 2015). We published the synthesis of triazolylcombretastatin A-4 analogs utilizing a [3 + 2]cycloaddition azide condensation reaction with sodium azide in the presence of l-proline as catalyst (Penthala et al., 2014a). In a continuation of our work on the chemical modification of the cyano group on the stilbene moiety of cyanocombretastatin A-4 analogs (Penthala et al, 2014a), we have recently synthesized tetrazolylcombretastatin A-4 analogs as potential anti-cancer agents (Penthala et al, 2016)

Structural commentary

Supramolecular features

Database survey

Synthesis and crystallization

Refinement details