Shridhar I. Panchamukhi

Synthesis and optoelectronic properties of symmetrical thiophene based 2,5-disubstiuted 1,3,4-oxadiazoles: highly fluorescent materials for OLED applications.

AbstractSymmetrical 2,5-disubstituted thiophene derivatives containing 1,3,4-oxadiazole moiety bearing different aromatic substitutions were synthesized by employing convenient and simple synthetic protocols using thiophene-2,5,dicarboxylic acid as a starting material. The structures of these target molecules were established by their analytical and spectral data. The photophysical and electrochemical studies were carried out on these compounds and found that they exhibit good fluorescent properties with high quantum yield. FigureSymmetrical 2,5-disubstituted thiophene derivatives containing the 1,3,4-oxadiazole moiety were synthesized from the corresponding thiophene 2,5-dicarboxylic acid. The Photophysical and electrochemical properties revealed that these compounds are good fluorescent materials with high quantum yield for OLED applications.

Synthesis and pharmacological evaluation of novel thienopyrimidine and triazolothienopyrimidine derivatives

Novel tricyclic thienopyrimidines (2, 3, 5, 8) and triazole-fused tetracyclic thienopyrimidines (6a–c and 9a–c) were synthesized from the precursor 2-amino-4,5,6,7-tetrahydro-1-benzothiophene-3-carbonitrile (1). The structures of newly synthesized compounds were established by spectral and analytical data. The title compounds were screened for analgesic, anti-inflammatory, ulcerogenicity index, and antibacterial activities. Test compounds exhibited significant activity, the compounds (6a–c) and (9a–c) showed more potent analgesic activity, and the compounds (6c) and (9c) showed more potent anti-inflammatory activity than the reference standard Diclofenac Sodium. All the synthesized compounds exhibited remarkable antibacterial activity.

Benzothieno[3,2-e][1,2,4]triazolo[4,3-c]pyrimidines: Synthesis, Characterization, Antimicrobial Activity, and Incorporation into Solid Lipid Nanoparticles

Fused triazolothienopyrimidines were prepared from the corresponding 2‐amino‐4,5,6,7‐tetrahydrobenzo[b]thiophene‐3‐carbonitrile. These precursors were intern prepared by employing the Gewalds reaction. All the newly synthesized compounds were characterized by spectral and analytical data. Title compounds displayed promising antibacterial and antifungal activities. Compound 3h which exhibited good antimicrobial activity was incorporated into SLN and characterized for particle size, entrapment efficiency (EE%), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and in‐vitro release studies. It showed narrow particle size distribution with high entrapment efficiency. In‐vitro release study of compound loaded SLNs in phosphate buffer of pH 7.4, exhibited a biphasic pattern with an initial burst and prolonged release over 24 h.

2-Phenyl-8,9,10,11-tetra­hydro-1-benzo­thieno[3,2-e][1,2,4]triazolo[1,5-c]pyrimidine

In the title compound, C17H14N4S, the benzothieno moiety is fused at one end of the pyramidine ring while the triazole ring with a phenyl substituent is fused at the other side. The triazole ring is almost planar [maximum deviation = 0.0028 (3) Å] while the cyclohexane ring adopts a half-chair conformation. In the crystal, pairs of intermolecular C—H⋯N hydrogen bonds form centrosymmetric head-to-head dimers, corresponding to an R 2 2(8) graph-set motif. Further C—H⋯N interactions generate a zigzag chain of molecules along the c axis. The supramolecular assembly is consolidated by π–π stacking interactions [centroid–centroid distance = 3.445 (4) Å].

2-Amino-6-methyl-4,5,6,7-tetra­hydro-1-benzothio­phene-3-carbonitrile

In the title compound, C10H12N2S, one of the C atoms of the cyclohexene ring (at position 6) and the methyl group attached to it are disordered over two sets of sites in a 0.650 (3):0.350 (3) ratio. The cyclohexene ring in both the major and minor occupancy conformers adopts a half-chair conformation. The thiophene ring is essentially planar (r.m.s. deviation = 0.05 Å). In the crystal, N—H⋯N hydrogen bonds involving the amino groups result in inversion dimers with R 2 2(12) graph-set motif. Further N—H⋯N hydrogen bonds involving the amino and carbonitrile groups generate zigzag chains along the a axis.

Crystal and Molecular Structure of 7-Methyl-5,6,7,8-tetrahydro[1]benzothieno[2,3-d]pyrimidin-4[3H]one

X-ray characterization of 7-methyl-5,6,7,8-tetrahydro[1]benzothieno [2,3-d]pyrimidin-4[3H]one is described. The compound crystallizes in the monoclinic space group P21/c with a=7.0013(2)A, b=8.3116(3)A, c=18.374(6)A, β=91.746(2)°, V=1068.76(6)A3, z=4. The structure was solved using the direct method and refined to reliability R-factor of 0.0639 using 3180 independent reflections The crystal structure is further stabilized by intermolecular C-H...N, N-H...N C-H...O, N-H...O, and π-π interactions.

7-Methyl-5,6,7,8-tetra-hydro-1-benzo-thieno[2,3-d]pyrimidin-4-amine.

In the title compound, C11H13N3S, two of the C atoms of the cyclohexene ring and the methyl group attached to it are disordered over two sets of sites in a 0.544 (2):0.456 (2) ratio. The benzothiene and pyrimidine rings are almost coplanar with an angular tilt of 2.371 (9)° between them. The thiophene ring is essentially planar (r.m.s. deviation 0.05 Å), while the cyclohexene ring in both the major- and minor-occupancy conformers adopts a half-chair conformation. In the crystal structure, pairs of intermolecular N—H⋯N hydrogen bonds involving the amino groups result in centrosymmetric head-to-head dimers about inversion centres, corresponding to an R 2 2(8) graph-set motif. Further, N—H⋯N hydrogen bonding generates a two-dimensional hydrogen-bonded network perpendicular to the ac plane and running along the diagonal of the ac plane.

2-Amino-7-oxo-4,5,6,7-tetra-hydro-1-benzothio-phene-3-carbonitrile.

In the title compound, C9H8N2OS, the benzothiophene ring is substituted with amino, oxo and carbonitrile groups. The thiophene ring is essentially planar (r.m.s. deviation = 0.0003 Å), while the cyclohexene ring is in a half-chair conformation. In the crystal, N—H⋯O hydrogen bonds generate chains of molecules in a zigzag pattern along the b axis. Pairs of N—H⋯N hydrogen bonds form centrosymmetric head-to-head dimers about inversion centres, corresponding to an R 2 2(12) graph-set motif. In addition, rather weak N—H⋯S interactions are also present in the structure and the supramolecular assembly is further consolidated by π–π stacking interactions between the benzothiophene rings, disposed at a distance of 3.742 (3) Å.