David J. Watkin

Benzyl N′-[1-(3-pyridyl)ethylidene]hydrazinecarbodithioate

The title compound, C15H5N2S2, crystallizes as a trans–cis conformer. The thione sulfur is in a trans position with the methyl pyridyl fragment with respect to the C—N bond but adopts a cis position with the benzyl ring across the C—S bond. The dihedral angle between the planar quinoline ring and the dithiocarbazate unit is 103.70 (1). The inclination of the dithiocarbazate unit with the benzyl group is 17.20 (1).There are strong – stacking interactions between pairs of dithiocarbazate units and also pairs of pyridine rings [3.27 (5)and 3.28 (5) A ° , respectively]. A long-distance intermolecular N—H N hydrogen bond [3.171 (2) A ° ] also stabilizes the structure.

2-C-Methyl-d-lyxono-1,4-lactone

The title compound, C6H10O5, has been crystallized for the first time, allowing the stereochemistry at C-2 and the ring size of the lactone to be firmly established.

Isopropyl 2,5-anhydro-6-azido-3,6-dide­oxy-d-xylo-hexonate

Determination of the crystal structure of the title isopropyl azido ester, C9H15N3O4, confirmed its relative stereochemistry and validated further work on the use of a derived sugar amino acid (SAA) as a peptidomimetic.

Iso­propyl 2,5-an­hydro-4-(2,5-an­hydro-4-azido-3-O-tert-butyl­di­phenyl­silyl-4-deoxy-l-ribonylamino)-3-O-tert-butyl­di­phenyl­silyl-4-deoxy-l-ribonate

The crystal structure of the title compound, C45H56N4O7Si2, shows a γ-turn conformation which is stabilized by an intramolecular hydrogen bond.

(1R,5S,8R)‐1,8‐Di­hydroxy‐6‐oxa‐3‐aza­bi­cyclo­[3.2.1]­octan‐2‐one

The crystal structure of the title bicyclic lactam, C6H9NO4, has firmly established the stereochemistry of the branched δ-sugar amino acid scaffold.

Bis{(Z)-[(E)-2-(pyridin-2-yl­methyl­idene)hydrazin-1-yl­idene][(pyridin-2-yl)methyl­sulfan­yl]methane­thiol­ato}nickel(II)

The title compound, [Ni(C13H11N4S2)2], was obtained by the reaction of S-2-picolyldithiocarbazate and pyridine-2-carbaldehyde with nickel(II) acetate. The NiII atom is located on a twofold rotation axis and is bonded to four N atoms at distances of 2.037 (8) and 2.109 (9) Å, and to two S atoms at a distance of 2.406 (3) Å, leading to a distorted octahedral coordination. The angle between the mean planes of the coordinating moieties of the two symmetry-related tridentate ligands is 83.3 (2)°. In the crystal, complex molecules are linked by weak C—H⋯S hydrogen bonds, π–π interactions between the pyridine rings [centroid–centroid distance = 3.775 (9) Å] and C—H⋯π interactions. The hydrogen-bonding interactions lead to the formation of layers parallel to (010); π–π interactions link these layers into a three-dimensional network.

2-Naphthylmethyl N-(3-pyridylmethylene) hydrazinecarbodithioate.

The title molecule, C18H15N3S2, is a trans-cis conformer. The thione S atom is in a trans configuration with respect to the pyridine ring but adopts a cis configuration with respect to the napthylmethyl substituent. In the crystal structure, molecules are linked by intermolecular N-H...N hydrogen bonds via[alpha]-N donor atoms and pyridyl N acceptor atoms into one-dimensional chains along the a axis. In addition, pairs of inversion-related dithiocarbazate groups and the attached pyridine groups are arranged with an interplanar distance 3.30 A, leading to [pi]-[pi] stacking interactions. The crystal used for the structure determination was twinned.

2-C-Methyl-3,4-O-methyl­idene-d-arabinono-1,5-lactone

The relative stereochemistry at C-2 of the title compound, C7H10O5, was determined by X-ray crystallographic analysis of the arabinonolactone, which adopts a boat conformation with a flagpole hydroxyl group. Its absolute configuration was determined by the use of d-erythronolactone as the starting material.

Methyl 2,4-an­hydro-5-azido-5,6-di­deoxy-l-altronate

The title compound, C7H11N3O4, was prepared from l-rhamnose as a conformationally restricted dipeptide isostere containing an oxetane ring. Its crystal structure was determined to confirm the synthetic product.

2,5-Bis(2-naphthylmethylsulfanyl)-1-thia-3,4-diazacyclopenta-2,5-diene

The title molecule, C24H18N2S3, consists of three essentially planar fragments viz. two methylnaphthalene groups and a five-membered thiadiazole ring. The dihedral angles between the two methylnaphthalene groups and the central 1-thia-3,4-diazacyclopenta-2,5-diene group are 78.9 (1) and 68.8 (1)°. In the crystal structure, - stacking interactions exist between pairs of symmetry-related naphthalene fragments with an interplanar separation of 3.35 A. All bond lengths and angles are comparable with previous reports except that both C-S bond lengths are slightly longer than normal. In addition, the C-S-C and S-C-C bond angles appear to be smaller than normal and this could be due to the steric hindrance of the methylnaphthalene fragments.