Ezhumalai Yamuna

Convergent Synthetic Route to Pyrano[2,3-a]carbazole by Multicomponent Reaction

Abstract NaHCO3 has been found to be an efficient base catalyst for the synthesis of pyrano[2,3-a]carbazoles from 1-hydroxycarbazoles by multicomponent reaction using solvent-free grinding methods. In this case, the products have been found in good yields, without formation of any side product. GRAPHICAL ABSTRACT

Elegant One-Pot Synthesis of Quinolino[2′,3′:7,6]-cyclohept[1,2-b]indole Through Friedländer and Pfitzinger Annulation Reaction

Abstract A rapid, simple, and efficient method for the preparation of various quinolino[2′,3′:7,6]cyclohept[1,2-b]indoles has been developed through the Friedländer and Pfitzinger condensations of 1-oxo-cyclohept[b]indole with o-amino benzophenone and isatin respectively. Reactions were performed by under different reaction conditions.

9-Ethyl-N-(3-nitro­benzyl­idene)-9H-carbazol-3-amine

The title compound, C21H17N3O2, crystallizes with two molecules 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-nitrobenzylideneamine and carbazole groups are 37.9 (1) and 37.0 (1)° in the two molecules.

Synthesis of quinolino[2',3':7,6]cyclohept[b]indoles and their antimicrobial activities

Practicable and concise syntheses of 6-chloro-7,8,9,14-tetrahydroquinolino[2′,3′:7,6]cyclohept[b]indoles by two routes are described. Both commenced with 1-oxo-2,3,4,5,10-hexahydrocyclohept[b]indoles and utilised either the acid-catalysed condensation with 2-aminobenzonitrile, followed by treatment with POCl3 or, better, direct condensation of the ketone with anthranilic acid in POCl3.

8-Methyl-2,3,4,9-tetra­hydro-1H-carbazol-1-one

In the title compound, C13H13NO, the dihedral angle between the benzene ring and the fused pyrrole ring is 0.96 (7)°. The cyclohexenone ring adopts an envelope conformation. Intermolecular N—H⋯O hydrogen bonds form R 2 2(10) ring motifs in the crystal structure. Weak C—H⋯π interactions involving the benzene ring also occur.

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

In the title molecule, C13H12ClNO, the dihedral angle between the benzene and pyrrole rings is 1.38 (9)°. The cycloheptene ring adopts a distorted twist chair and sofa conformation. Intermolecular 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) interactions are found in the crystal structure.

(E)-2-[(Furan-2-yl)methyl­idene]-7-methyl-2,3,4,9-tetra­hydro-1H-carbazol-1-one

In the title molecule, C18H15NO2, 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 cyclohexene ring adopts a half-chair conformation. In the crystal, pairs of N—H⋯O hydrogen bonds form an R 2 2(10) ring. Molecules are further linked by C—H⋯O and C—H⋯π interactions, forming a three-dimensional network.

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

In the title compound, C17H12ClNO2, 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. Intermolecular N—H⋯O hydrogen bonds form R 2 2(10) rings in the crystal structure.

5-Methyl-7,8,9,10-tetra­hydro­cyclo­hepta­[b]indol-6(5H)-one

In the title molecule, C14H15NO, the dihedral angle between the benzene and pyrrole rings is 1.99 (12)°. The cycloheptene ring adopts a slightly distorted boat conformation.