Abstract
The title compound, C19H17N3O3S (I), was prepared by a [3+2]cyclo-addition azide condensation reaction using sodium azide and l-proline as a Lewis base catalyst. N-Methyl-ation of compound (I) using CH3I gave compound (II), C20H19N3O3S. The benzo-thio-phene ring systems in (I) and (II) are almost planar, with r.m.s deviations from the mean plane = 0.0205 (14) in (I) and 0.016 (2) Å in (II). In (I) and (II), the triazole rings make dihedral angles of 32.68 (5) and 10.43 (8)°, respectively, with the mean planes of the benzo-thio-phene ring systems. The trimeth-oxy phenyl rings make dihedral angles with the benzo-thio-phene rings of 38.48 (4) in (I) and 60.43 (5)° in (II). In the crystal of (I), the mol-ecules are linked into chains by N-H⋯O hydrogen bonds with R (2) 1(5) ring motifs. After the N-methyl-ation of structure (I), no hydrogen-bonding inter-actions were observed for structure (II). The crystal structure of (II) has a minor component of disorder that corresponds to a 180° flip of the benzo-thio-phene ring system [occupancy ratio 0.9363 (14):0.0637 (14)].
Highlights
The title compound, C19H17N3O3S (I), was prepared by a [3 + 2]cycloaddition azide condensation reaction using sodium azide and l-proline as a Lewis base catalyst
The crystal structure of (II) has a minor component of disorder that corresponds to a 180 flip of the benzothiophene ring system [occupancy ratio 0.9363 (14):0.0637 (14)]
In continuation of our work on the development of benzothiophene cyano combretastatin A-4 analogs as anti-cancer agents (Penthala et al, 2013), we have synthesized a series of novel CA-4 analogs by constructing a triazole ring structure (I) by chemical modification of the cyano group on the stilbene unit of cyano-CA-4 analogs utilizing a [3 + 2]cycloaddition azide condensation reaction with sodium azide in the presence of l-proline Lewis base as catalyst
Summary
In continuation of our work on the development of benzothiophene cyano combretastatin A-4 analogs as anti-cancer agents (Penthala et al, 2013), we have synthesized a series of novel CA-4 analogs by constructing a triazole ring structure (I) by chemical modification of the cyano group on the stilbene unit of cyano-CA-4 analogs utilizing a [3 + 2]cycloaddition azide condensation reaction with sodium azide in the presence of l-proline Lewis base as catalyst. This chemical modification is essential to restrict the tendency toward cis–trans isomerization of the cyano-stilbene moiety in cyano-CA-4 analogs (Penthala et al, 2013).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Acta crystallographica. Section E, Structure reports online
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
