Synthesis and crystal structure of 1-hy-droxy-8-methyl-9H-carbazole-2-carbaldehyde.

Two crystallographically independent mol-ecules are present in the asymmetric unit of the title compound, C14H11NO2, with virtually identical geometries. The carbazole units are planar. The hy-droxy group at position 1, carbaldehyde group at position 2, and methyl group at position 8 (with the exception of two H atoms) are coplanar with the attached benzene rings. The dihedral angle between the two benzene rings is 2.20 (9)° in mol-ecule A and 2.01 (9)° in mol-ecule B. The pyrrole ring makes dihedral angles of 0.82 (10) and 1.40 (10)° [0.84 (10) and 1.18 (10)° in mol-ecule B] with the (-CH3)-substituted and (-OH and -CHO) substituted benzene rings, respectively. The mol-ecular structure is stabilized by the intra-molecular O-H⋯O hydrogen bonds, while the crystal structure features N-H⋯O and C-H⋯O hydrogen bonds. A range of π-π contacts further stabilizes the crystal structure.

Crystal structure of (E)-2-(furan-2-yl-methyl-idene)-2,3,4,9-tetra-hydro-1H-carbazol-1-one.

The title compound, C17H13NO2, crystallizes with two conformationally very similar independent mol-ecules (A and B) in the asymmetric unit. In the crystal, the individual mol-ecules are linked by pairs of N-H⋯O hydrogen bonds forming A-A and B-B inversion dimers, with R22(10) rings. They stack alternately up the a-axis direction and are linked by C-H⋯π inter-actions, forming sheets parallel to the ab plane.

Benzoquinoline amines - Key intermediates for the synthesis of angular and linear dinaphthonaphthyridines.

A systematic study on the condensation reaction of 2,4-dichlorobenzo[h]quinoline and naphth-1-ylamine in the presence of CuI as catalyst to functionalised mono- and di-substituted (naphthalen-1-yl)benzo[h]quinoline amines was described. Subsequently these mono- and di-substituted amines on polyphosphoric acid catalysed cyclisation reaction with aromatic/heteroaromatic carboxylic acids led to the construction of angular and linear aromatic/heteroaromatic substituted dinaphthonaphthyridines in good yields.

In vivo anti-diabetic, antioxidant and molecular docking studies of 1, 2, 8-trihydroxy-6-methoxy xanthone and 1, 2-dihydroxy-6-methoxyxanthone-8-O-ß-D-xylopyranosyl isolated from Swertia corymbosa.

1, 2, 8-trihydroxy-6-methoxy xanthone (1) and 1, 2- dihydroxy-6-methoxyxanthone-8-O-ß-d-xylopyranosyl (2) are the main constituents of petroleum ether and ethyl acetate extracts from Swertia corymbosa (Gentinaceae), a medicinal plant used in Indian traditional system for the treatment of diabetes. The present study was designed to examine the antihypoglycemic, antihyperlipidemic and antioxidant effect of compounds 1 and 2 in streptozotocin (STZ) induced diabetic rats. Diabetes was induced in male Wistar rats by a single intraperitoneal injection of STZ (60 mg/kg b.w.). The isolated compounds 1 and 2 at a dose of 50 mg/kg b.w., produced the maximum fall of 83% in the blood glucose level in the diabetic rats after 3h of the treatment. The administration of 1 and 2 (50 mg/kgb.w.) daily for 28 days in STZ induced diabetic rats, resulted in a significant decrease in blood glucose, glycosylated hemoglobin, SGOT, SGPT, ALP serum urea and creatinine with significant rise in plasma insulin level. Test compounds 1 and 2 showed antihyperlipidemic activities as evidenced by significant decrease in serum TC, TG, LDL-C, VLDL-C levels coupled together with elevation of HDL-C level in diabetic treated rats when compared to diabetic untreated rats, indicate the protective role against liver and kidney damage. The results of histopathology also showed 1 and 2 protected tissues (pancreas, liver and kidney) against peroxidation damage and maintained tissue integrity. Further, the molecular interaction study of the ligands 1, 2 and glibenclamide with various diabetes mellitus related protein targets like glucokinase (PDB ID: 1V4S), fructose-1, 6-bisphosphatase 1 (PDB ID: 2JJK) 11-ß-hydroxysteroid dehydrogenase (PDB ID: 2BEL) and modeled protein sulfonylurea receptor 1 (SUR1) showed that ligand 1 and 2 possess binding affinity with all protein targets except for 2BEL target protein for which ligand 1 has no interaction. The ligand pose with 2BEL and SUR1 protein target of ligand 2 gave the best binding conformation. Hence 1 and 2 can be considered for developing into a potent antidiabetic drug.

Solvent-free synthesis of heteroannulated carbazoles: a novel class of anti-tumor agents.

A series of novel carbazole analogues that hold pyrido, isoxazolo, pyrimido and pyrazolo templates were designed and synthesised in good yield by grinding conditions. All the synthesised compounds were screened for their anti-tumor activity and displayed enviable selective growth inhibition on HeLa cell line compared to AGS cell line. Among these compounds, compound 2-(3',4'-diethoxy-benzylidene)-6-methyl-2,3,4,9-tetrahydro-carbazol-1-one,6-chloro-2-(3',4'-diethoxy-benzylidene)-2,3,4,9-tetrahydro-carbazol-1one, 2-(3',4'-diethoxy-benzylidene)-8-methyl-2,3,4,9-tetrahydro-carbazol-1-one, 3-(3',4'-diethoxyphenyl)-7-methyl-4,5-dihydro-10H-isoxazolo[3,4-a]carbazole, 7-chloro-3-(3',4'-diethoxyphenyl)-4,5-dihydro-10H-isoxazolo[3,4-a]carbazole, 4-(3',4'-diethoxyphenyl)-2-ethoxy-8-methyl-6,11-dihydro-5H-pyrido[2,3-a]carbazole-3-nitrile, 8-chloro-4-(3',4'-diethoxyphenyl)-2-ethoxy-6,11-dihydro-5H-pyrido[2,3-a]carbazole-3-nitrile, 4-(3',4'-diethoxyphenyl)-2-ethoxy-10-methyl-6,11-dihydro-5H-pyrido[2,3-a]carbazole-3-nitrile were found to have promising anti-tumor properities with reference to the standard ellipticine against the HeLa cancer cell line. All these intermediates showed IC50 outranged the standard ellipticine. The same compounds showed moderate activity against AGS cancer cell lines. The efforts were undertaken to optimize potency and selectivity of this class of compounds.

10-Methyl-2-oxo-4-phenyl-2,11-di-hydro-pyrano[2,3-a]carbazole-3-carbo-nitrile.

In the title mol-ecule, C23H14N2O2, the atoms in the carbazole unit deviate from planarity [maximum deviation from mean plane = 0.1018 (8) Å]. The pyrrole ring makes dihedral angles of 4.44 (5), 3.84 (5), 2.18 (5) and 56.44 (5)° with the pyran, fused benzene rings and phenyl ring, respectively. In the crystal, pairs of N-H⋯O hydrogen bonds generate R 2 (2)(14) loops and a C-H⋯N inter-action is also found. Mol-ecules are further linked by a number of π-π interactions [centroid-centroid distances vary from 3.5702 (5) to 3.7068 (6) Å], forming a three-dimensional network.

7-Methyl-1-phenyl-1,10-di-hydro-pyrazolo-[3,4-a]carbazole.

In the title mol-ecule, C20H15N3, the atoms in the carbazole unit deviate from planarity [maximum deviation from mean plane = 0.1082 (15) Å]. The pyrrole ring makes dihedral angles of 3.17 (8)/4.10 (9), 7.20 (9) and 44.62 (9)° with the fused benzene, pyrazole and phenyl rings, respectively. In the crystal, mol-ecules are linked via N-H⋯N hydrogen bonds, forming an infinite chain along [010]. Mol-ecules are further linked by nine π-π [centroid-centroid distances vary from 3.6864 (11) to 3.9802 (11) Å] and one C-H⋯π inter-action, forming a three-dimensional network.

(E)-2-[(Furan-2-yl)methyl-idene]-7-methyl-2,3,4,9-tetra-hydro-1H-carbazol-1-one.

In the title mol-ecule, C(18)H(15)NO(2), the atoms in the carbazole unit deviate from planarity [maximum deviation from mean plane = 0.1317 (12) Å]. The pyrrole ring makes dihedral angles of 1.01 (8) and 18.56 (10)° with the benzene and furan rings, respectively. The cyclo-hexene ring adopts a half-chair conformation. In the crystal, pairs of N-H⋯O hydrogen bonds form an R(2) (2)(10) ring. Mol-ecules are further linked by C-H⋯O and C-H⋯π inter-actions, forming a three-dimensional network.

2-Chloro-7,8,9,10-tetra-hydro-cyclo-hepta-[b]indol-6(5H)-one.

In the title mol-ecule, C(13)H(12)ClNO, the dihedral angle between the benzene and pyrrole rings is 1.38 (9)°. The cyclo-heptene ring adopts a distorted twist chair and sofa conformation. Inter-molecular N-H⋯O hydrogen bonds form an R(2) (2)(10) loop in the crystal packing. Further, weak C-H⋯O and C-H⋯π (involving the benzene ring) inter-actions are found in the crystal structure.

L-Proline anchored multicomponent synthesis of novel pyrido[2,3-a]carbazoles; investigation of in vitro antimicrobial, antioxidant, cytotoxicity and structure activity relationship studies.

The newly synthesized pyrido[2,3-a]carbazoles were prepared in good yields by multicomponent reactions under L-proline as promoter and structurally characterized. Few compounds showed significant activity toward both gram-positive, gram-negative bacterial strains. All compounds exerted negative efficacy for antifungal activity except compounds 5f and 7f which showed moderate activity. All compounds showed weak to moderate capacity for scavenging DPPH. The cytotoxicity was evaluated by Sulforhodamine B assay against A-549, B16F10, HCT-15, SKMel2 and SKOV3 cell lines and compared with standard drug cisplatin. Compound 5f outperformed cisplatin against A-549, HCT-15, SKMel2 and B16F10 cell lines. Compound 5e outranged cisplatin against A-549, HCT-15, and SKMel2 cell lines. 5b outperformed cisplatin specifically against B16F10. The preliminary structure activity relationships were carried out.

6-Methyl-2,3,4,9-tetra-hydro-1H-carbazole-1-thione.

In the title mol-ecule, C(13)H(13)NS, the dihedral angle between the benzene ring and the fused pyrrole ring is 0.71 (8)° and the cyclo-hexene ring is in an envelope form. The (CH(2))(3) atoms of the cyclo-hexene ring are disordered over two positions; the site-occupancy factor for the major component refined to 0.862 (4). In the crystal, inter-molecular N-H⋯S hydrogen bonds lead to the formation of centrosymmetric aggregates via an R(2) (2)(10) ring.

9-Ethyl-N-(3-nitro-benzyl-idene)-9H-carbazol-3-amine.

The title compound, C(21)H(17)N(3)O(2), crystallizes with two mol-ecules in the asymmetric unit. The carbazole groups show relatively small deviations from planarity [maximum displacements from the mean carbazole plane are 0.077 (7) and 0.101 (7) Å]. The dihedral angles between the 3-nitro-benzyl-idene-amine and carbazole groups are 37.9 (1) and 37.0 (1)° in the two mol-ecules.

5-Methyl-7,8,9,10-tetra-hydro-cyclo-hepta-[b]indol-6(5H)-one.

In the title mol-ecule, C(14)H(15)NO, the dihedral angle between the benzene and pyrrole rings is 1.99 (12)°. The cyclo-heptene ring adopts a slightly distorted boat conformation.

2-(2,3,4,9-Tetra-hydro-1H-carbazol-1-ylidene)propane-dinitrile.

In the title mol-ecule, C(15)H(11)N(3), the dihedral angle between the benzene ring and the fused pyrrole ring is 1.07 (5)°. The cyclo-hexene ring adopts an envelope conformation: the dicyano-methyl-ene group at position 1 has a coplanar orientation. An intra-molecular N-H⋯N hydrogen bond generates an S(7) ring motif. Inter-molecular N-H⋯N hydrogen bonds form an R(2) (2)(14) ring in the crystal. A C-H⋯π inter-action involving the benzene ring is also found in the structure.

8-Methyl-2,3,4,9-tetra-hydro-1H-carbazol-1-one.

In the title compound, C(13)H(13)NO, the dihedral angle between the benzene ring and the fused pyrrole ring is 0.96 (7)°. The cyclohexenone ring adopts an envelope conformation. Inter-molecular N-H⋯O hydrogen bonds form R(2) (2)(10) ring motifs in the crystal structure. Weak C-H⋯π inter-actions involving the benzene ring also occur.

2,5-Dimethyl-7,8,9,10-tetra-hydro-cyclo-hepta-[b]indol-6(5H)-one.

In the title mol-ecule, C(15)H(17)NO, the dihedral angle between the benzene and pyrrole rings is 1.45 (13)°. The cyclo-heptene ring adopts a slightly distorted boat conformation. In the crystal structure, inter-molecular C-H⋯O hydrogen bonds are found.

(E)-2-(Furan-2-yl-methyl-idene)-8-methyl-2,3,4,9-tetra-hydro-1H-carbazol-1-one.

In the title mol-ecule, C(18)H(15)NO(2), the carbazole unit is not planar [maximum deviation from mean plane = 0.236 (2) Å]. The pyrrole ring makes dihedral angles of 1.21 (10) and 16.74 (12)° with the benzene and the furan rings, respectively. The cyclo-hexene ring adopts a half-chair conformation. In the crystal, inversion dimers linked by pairs of N-H⋯O hydrogen bonds generate R(2) (2)(10) loops.

1-(1-Hy-droxy-8-methyl-9H-carbazol-2-yl)ethanone.

The title compound, C(15)H(13)NO(2), crystallizes with four independent mol-ecules (A, B, C and D) in the asymmetric unit. The carbazole units are almost planar [maximum deviations = 0.015 (3) for A, 0.024 (3) for B, 0.026 (3) for C and 0.046 (3) Šfor D]. In all four mol-ecules, there is an O-H⋯O hydrogen bond involving the hy-droxy substituent and the carbonyl O atom of the adjacent acetyl group, which forms a six-membered ring. In the crystal, the four independent mol-ecules are linked via N-H⋯O and C-H⋯O inter-actions.

(E)-6-Chloro-2-(furan-2-yl-methyl-idene)-2,3,4,9-tetra-hydro-1H-carbazol-1-one.

In the title compound, C(17)H(12)ClNO(2), the carbazole unit is nearly planar [maximum deviation = 0.052 (1) Å]. The pyrrole ring makes dihedral angles of 1.92 (8) and 4.71 (11)° with the benzene and furan rings, respectively. Inter-molecular N-H⋯O hydrogen bonds form R(2) (2)(10) rings in the crystal structure.

4-Methyl-7,8,9,10-tetra-hydro-cyclo-hepta-[b]indol-6(5H)-one.

In the title compound, C(14)H(15)NO, the seven-membered ring exhibits a slightly distorted twist-boat conformation. The pyrrole ring forms a dihedral angle of 1.44 (10)° with the fused benzene ring. N-H⋯O hydrogen bonds form a centrosymmetric dimer and weak C-H⋯π inter-actions are also found in the crystal structure.