Nickel-Catalyzed Direct Alkenylation of Methyl Heteroarenes with Primary Alcohols.

An efficient nickel-catalyzed acceptorless dehydrogenative coupling of methyl-substituted heteroarenes with primary alcohols is achieved using an in situ generated complex of inexpensive NiBr2 and readily available 8-aminoquinoline picolinic amide ligand. The protocol is operationally simple and scalable and furnishes a series of high-value 2-alkenylheteroarenes in good yields (up to 88%) with exclusive E-selectivity. The reaction proceeds with the release of water and molecular hydrogen, which was analyzed through gas chromatography to validate the reaction mechanism.

Crystal structures of three indole derivatives: 3-ethnyl-2-methyl-1-phenyl-sulfonyl-1H-indole, 4-phenyl-sulfonyl-3H,4H-cyclo-penta-[b]indol-1(2H)-one and 1-{2-[(E)-2-(5-chloro-2-nitro-phen-yl)ethen-yl]-1-phenyl-sulfonyl-1H-indol-3-yl}ethan-1-one chloro-form monosolvate.

The title compounds, C17H13NO2S, (I), C17H13NO3S, (II), and C24H17ClN2O5S·CHCl3, (III), are indole derivatives. Compounds (I) and (II) crystalize with two independent mol-ecules in the asymmetric unit. The indole ring systems in all three structures deviate only slightly from planarity, with dihedral angles between the planes of the pyrrole and benzene rings spanning the tight range 0.20 (9)-1.65 (9)°. These indole ring systems, in turn, are almost orthogonal to the phenyl-sulfonyl rings [range of dihedral angles between mean planes = 77.21 (8)-89.26 (8)°]. In the three compounds, the mol-ecular structure is stabilized by intra-molecular C-H⋯O hydrogen bonds, generating S(6) ring motifs with the sulfone O atom. In compounds (I) and (II), the two independent mol-ecules are linked by C-H⋯O hydrogen bonds and C-H⋯π inter-actions, while in compound (III), the mol-ecules are linked by C-H⋯O hydrogen bonds, generating R 2 (2)(22) inversion dimers.

Synthesis of calothrixins and its analogs using FeCl3-mediated domino reaction protocol.

A novel one pot synthesis of calothrixin B and its analogs is achieved involving an FeCl3-mediated domino reaction of enamines in dry DMF at reflux. Alternatively, the enamines upon interaction with CuBr2 in DMF at reflux led to the formation of 1-phenylsulfony-2-(2'-nitroaryl)-4-hydroxycarbazole-3-carbaldehydes in excellent yields.

2-(4-Chloro-2-nitro-phen-yl)-9-phenyl-sulfonyl-9H-carbazole-3-carbaldehyde.

In the title compound, C25H15ClN2O6S, the carbazole ring system is essentially planar, with a maximum deviation of 0.152 (3) Šfor the C atom to which the 4-chloro-2-nitro-phenyl ring is attached. Its mean plane is almost orthogonal to the phenyl-sulfonyl and nitro-phenyl rings, making dihedral angles of 82.64 (14) and 79.89 (13)°, respectively. The N atom of the nitro group deviates by 0.032 (3) Šfrom the benzene ring to which it is attached. The mol-ecular structure features intra-molecular O-H⋯O and C-H⋯O hydrogen bonds, which generate three S(6) ring motifs. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, which generate C(6) and C(9) chains running in the [100] and [010] directions, respectively, forming a two-dimensional network lying parallel to (001). There are also R 4 (3)(28) supra-molecular graph-set ring motifs enclosed within these networks.