Abstract
The crystal structures of three isomeric (E)-N'-(chloro-phenyl-methyl-idene)-N-methyl-2-(thio-phen-2-yl)acetohydrazides (C14H13ClN2OS) are described, with the Cl atom in ortho (I), meta (III) and para (IV) positions in the benzene ring. The ortho-bromo derivative (II) (C14H13BrN2OS), which is isostructural with its chloro congener (I), is also reported. Mol-ecules (I)-(III) have similar conformations, which approximate to l-shapes, as indicated by their N-C-C-Ct (t = thio-phene) torsion angles of -90.1 (3), -91.44 (18) and -90.7 (9)°, respectively. The conformation of (IV) is different, with an equivalent torsion angle of -170.75 (11)° corresponding to a more extended shape for the mol-ecule. The thio-phene ring in each structure features 'flip' rotational disorder. The packing for (I) and (II) features inversion dimers, linked by pairs of C-H⋯O inter-actions, which generate R22(14) loops. In the crystal of (III), [010] C(8) chains arise, with adjacent mol-ecules linked by pairs of C-H⋯O hydrogen bonds. The packing for (IV) features unusually short C-H⋯O inter-actions arising from an H atom attached to the benzene ring (H⋯O = 2.18 Å), which lead to C(9) [301] chains. Hirshfeld fingerprint percentage contact contributions are similar for the four title compounds.
Highlights
The packing for (I) and (II) features inversion dimers, linked by pairs of C— HÁ Á ÁO interactions, which generate R22(14) loops
We have reported the syntheses and anti-TB activities of acetamido derivatives, 2-(R,R0NCOCH2)-thiophene, R = alkyl (Nora de Souza et al, 2008), and more recently thienyl acetohydrazide derivatives, 2-(ArCH N—NHCOCH2)-thiophene (Cardoso et al, 2014)
The biological activities of these compounds will be reported elsewhere: here, we present the crystal structures of three isomeric chloro derivatives in this family bearing a halogen atom at different sites on the benzene ring, viz. (E)-N0-(2-chlorophenylmethylidene)-Nmethyl-2-(thiophen-2-yl)acetohydrazide (I), (E)-N0-(2-bromophenylmethylidene)-N-methyl-2-(thiophen-2-yl)acetohydrazide (II), (E)-N0-(3-chlorophenylmethylidene)-N-methyl-2-(thiophen-2-yl)acetohydrazide (III) and (E)-N0-(4-chlorophenylmethylidene)-N-methyl-2-(thiophen-2-yl)acetohydrazide (IV)
Summary
We are studying the related family of methylated 2-[ArCH N—N(CH3)COCH2]-thiophene compounds, with different substituents attached to the benzene ring. (E)-N0-(2-chlorophenylmethylidene)-Nmethyl-2-(thiophen-2-yl)acetohydrazide (I), (E)-N0-(2-bromophenylmethylidene)-N-methyl-2-(thiophen-2-yl)acetohydrazide (II), (E)-N0-(3-chlorophenylmethylidene)-N-methyl-2-(thiophen-2-yl)acetohydrazide (III) and (E)-N0-(4-chlorophenylmethylidene)-N-methyl-2-(thiophen-2-yl)acetohydrazide (IV). The biological activities of these compounds will be reported elsewhere: here, we present the crystal structures of three isomeric chloro derivatives (and one bromo derivative) in this family bearing a halogen atom at different sites on the benzene ring, viz. These complement our recent structural study (Cardoso et al, 2016a) of isomeric ortho-, meta- and para-nitro derivatives in the same family
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 call
