J. Saravanan

N-(X-Methylphenyl)-2-{(Z)-[(2,3,4-trimethoxyphenyl)methylidene]amino}-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide, where X = 2 and 3.

The title isomers, viz. the N-(3-methylphenyl)-, (I), and N-(2-methylphenyl)-, (II), derivatives, both C(26)H(28)N(2)O(4)S, adopt an E configuration that places the thiophene and trimethoxyphenyl groups on opposite sides of the C=N double bond, providing a suitable orientation for formation of an intramolecular N-H...N hydrogen bond. However, while the molecule in (I) is close to being planar, the N-methylphenyl group in (II) is twisted significantly from the plane of the remainder of the molecule. Both crystal structures are essentially layered and there are no intermolecular N-H...O hydrogen bonds. Compound (I) has a significantly higher calculated density than (II) (1.340 cf 1.305 Mg m(-3)), indicating that the molecular packing in the meta isomer is overall more efficient than that in the ortho isomer.

Methyl 2-(acetylamino)-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxylate

The title compound, C12H15NO3S, exhibits antibacterial and antifungal activities. The cyclohexene ring exhibits disorder,indicating two possible conformations of the half-chair form.The molecular structure is approximately planar, supported byan intramolecular N–H...O hydrogen bond.

2-Amino-N-(2-chlorophenyl)-4,5,6,7-tetra-hydro-1-benzothiophene-3-carboxamide

The title compound,

Two biologically active thiophene- 3-carboxamide derivatives

{C_{15}H_{15}ClN_{2}OS}

4,5-Dimethyl-N-(2-methylphenyl)-2-

, shows antibacterial and antifungal activities. The dihedral angle between the thiophene moiety and the 2-chlorophenyl ring is

\{[(1E)-(3,4,5-trimethoxyphenyl)methylene]amino\}

22.3(1)^{\mathtrm{0}}

thiophene-3-carboxamide

. There are intramolecular N–H...O and N–H... Cl hydrogen bonds and an intramolecular C–H...O interaction, which remove the conformational fexibility. Also intermolecular N–H...Ointeractions form chains of molecules in the crystal structure.

2-[(E)-Benzyl­ideneamino]-N-(2-fluoro­phenyl)-4,5,6,7-tetrahydro-1-benzothio­phene-3-carboxamide

The two title compounds, 2-([(1Z)-[4-(dimethylamino)phenyl]methylene]amino)-4,5-dimethyl-N-(2-methylphenyl)thiophene-3-carboxamide, C(23)H(25)N(3)OS, (I), and 2-([(1E)-[4-(dimethylamino)phenyl]methylene]amino)-N-(4-methylphenyl)-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide,C(25)H(27)N(3)OS, (II), show antibacterial and antifungal activities. The asymmetric unit of (II) contains two crystallographically independent molecules. The o-toluidine ring in (I) lies gauche with respect to the thiophene ring. In (II), the p-toluidine ring is coplanar with the thiophene ring in one molecule, but is tilted from it in the other molecule. Neither structure exhibits any significant intermolecular interactions, but in both, an intramolecular N-H.N hydrogen bond forms a pseudo-six-membered ring, thus locking the molecular conformation and removing conformational flexibility.

2-(Acetamido)-4,5-dimethyl-N-(2-methyl-phenyl)thiophene-3-carboxamide

The conformation of the title molecule,

2-Amino-N-(2-chloro­phenyl)-5,6-di­hydro-4H-cyclo­penta­[b]­thio­phene-3-carbox­amide

C_{24}H_{26}N_2O_4S