D. Gayathri

r-2,c-6-Bis(4-fluoro-phen-yl)-t-3,t-5-dimethyl-piperidin-4-one.

In the title compound, C19H19F2NO, the piperidinone ring adopts a chair conformation. The crystal packing is stabilized by C—H⋯O and C—H⋯F intermolecular interactions, generating centrosymmetric dimers of R 2 2(14) and R 2 2(24) rings.

Ethyl 1-(2-bromo­propano­yl)-4-hydr­oxy-2,6-diphenyl-1,2,5,6-tetra­hydro­pyridine-3-carboxylate

The title compound, C23H24BrNO4, crystallizes with two independent molecules per asymmetric unit. The methyl group of the ethoxycarbonyl unit is disordered over two positions, with occupancies of 0.715 (12) and 0.285 (12) in one of the independent molecules, and 0.529 (11) and 0.471 (11) in the other molecule. In one of the independent molecules, the tetrahydropyridine ring adopts a half-chair conformation, while in the other it is in a distorted envelope conformation. In each independent molecule, an intramolecular O—H⋯O hydrogen bond generates an S(6) ring motif. The two independent molecules are linked via C—H⋯O hydrogen bonds, forming a chain along the c axis.

1-(4-Methyl-phen-yl)-1H-1,2,3,4-tetra-zole.

In the title compound, C8H8N4, the dihedral angle between the tetrazole and benzene rings is 21.6 (1)°. An intermolecular C—H⋯π interaction is observed.

Bis(S-benzyl­isothio­uronium) tetra­chloridozincate(II)

The asymmetric unit of the title compound, (C8H11N2S)2[ZnCl4], contains two S-benzylisothiouronium cations which differ in the C—C—S—C torsion angle [165.3 (2) and 81.9 (2)°] and a tetrahedral tetrachloridozincate anion. The crystal structure is stabilized by N—H⋯Cl, C—H⋯Cl and C—H⋯S interactions.

4′-Amino-2,2′′-dioxo-2,2′′,3,3′′-tetra­hydro-1H-indole-3-spiro-1′-cyclo­pent-3′-ene-2′-spiro-3′′-1H-indole-3′,5′,5′-tricarbonitrile dihydrate

In the title compound, C22H12N6O2·2H2O, the cyclopentene ring adopts an envelope conformation, with the spiro C atom bonded to the dicyano-substituted C atom deviating by 0.437 (2) Å from the plane of the remaining four atoms in the ring. The puckering and smallest displacement asymmetry parameters for the ring are q 2 = 0.275 (2) Å, ϕ = 212.4 (4)° and Δs(C2) = 2.7 (2). The dihedral angle between the two indole groups is 60.1 (1)°. The structure contains intermolecular N—H⋯O hydrogen bonds involving the indole groups and O—H⋯O and O—H⋯N hydrogen bonds involving the water molecules.

(3aR,6S,6aR)-6-Benzyl-1-(4-bromophenyl)-5-tosyl-cis-perhydropyrrolo[3,4-b]pyrrole

The title compound, C26H27BrN2O2S, has two fused pyrrolidine rings, each in a twist conformation.

Crystal structures of the Schiff base derivatives (E)-N′-[(1H-indol-3-yl)methyl­idene]isonicotino­hydrazide ethanol monosolvate and (E)-N-methyl-2-[1-(2-oxo-2H-chromen-3-yl)ethyl­idene]hydrazinecarbo­thio­amide

In the two title Schiff base derivatives, the (E)-N′-[(1H-indol-3-yl)methylidene]isonicotinohydrazide molecules and (E)-N-methyl-2-[1-(2-oxo-2H-chromen-3-yl)ethylidene]hydrazinecarbothioamide molecules form a tape structure and a helical chain structure, respectively, through hydrogen bonds.

Crystal structure of 2-cyano-N-(furan-2-ylmeth­yl)acetamide

In the title compound, C8H8N2O2, the acetamide unit is inclined to the furan ring by 76.7 (1)°. In the crystal, molecules are linked by N—H⋯O and C—H⋯O hydrogen bonds, generating C(4) chains along [100]. The carbonyl O atom is a bifurcated acceptor and an R 1 2(6) ring is formed.

(Z)-Ethyl 2-cyano-3-(1H-imidazol-2-yl)acrylate

The crystal structure of the title compound, C9H9N3O2, features N—H⋯N and C—H⋯O interactions. The N—H⋯N interaction generates a chain running along the a axis and the C—H⋯O interaction generates a chain along the c axis. An intramolecular C—H⋯O interaction is also observed.

(E)-Ethyl 2-cyano-3-(furan-2-yl)acrylate.

There are two independent molecules in the asymmetric unit of the title compound, C10H9NO3, in both of which, all non-H atoms except for the methyl C atom lie nearly in the same plane [maximum deviations = 0.094 (3) and 0.043 (2) Å]. In the crystal, each independent molecules is linked by pairs of C—H⋯O interactions, generating inversion dimers with R 2 2(10) ring motifs.