A versatile synthetic procedure is described to prepare the benzimidazole-fused 1,2,4-thiadiazoles 2a-c via a methanesulfonyl chloride initiated multistep cyclization involving the intramolecular reaction of an in-situ generated carbodiimide with a thiourea unit. The structure of the intricate heterocycle 2a was confirmed by single-crystal X-ray analysis and its mechanism of formation supported...

The heterocycle in the title compound {systematic name: (5S)-5-[(1S)-1-methyl-prop-yl]pyrrolidine-2,4-dione}, C(8)H(13)NO(2), is planar (r.m.s. deviation for all non-H atoms = 0.008 Å). The crystal structure is stabilized by N-H⋯O hydrogen bonding.

The title compound, C(15)H(15)BrO(2), was synthesized by a Brønsted acid-catalysed domino electrocyclization-halogenation reaction. The five-membered ring is essentially planar (r.m.s. deviation 0.006 Å) and forms a dihedral angle of 72.7 (3)° with the attached phenyl ring. The six-membered heterocycle adopts a half-chair conformation. The crystal packing is stabilized by a C-H⋯O contact.

The first enantioselective synthesis of the anti-Helicobacter pylori agent (+)-spirolaxine methyl ether has been carried out in a convergent fashion by heterocycle-activated Julia olefination of a spiroacetal-containing sulfone fragment with a phthalide-containing aldehyde fragment. The total synthesis of (+)-spirolaxine methyl ether establishes the absolute stereochemistry of the natural produ...

Reaction of cellular thiols with the 1,2-dithiolan-3-one 1-oxide moiety of leinamycin triggers the generation of DNA-damaging reactive intermediates. Studies with small, synthetic analogues of leinamycin reveal that the macrocyclic portion of the natural product imparts remarkable hydrolytic stability to the 1,2-dithiolan-3-one 1-oxide heterocycle without substantially compromising its thiol-se...

The six-membered heterocycle in the title compound, C(18)H(16)BrN(3)O(4)S, adopts a sofa conformation. Intra-molecular N-H⋯N and O-H⋯O hydrogen bonds stabilize the mol-ecular conformation by forming a five- and a six-membered ring, respectively. The crystal packing is stabilized by inter-molecular C-H⋯O hydrogen bonds.

The mol-ecule of the title compound, C(22)H(23)N(3)O(3), exists in the enamine-keto form. A strong intra-molecular N-H⋯O hydrogen bond occurs, generating an S(6) ring. The dihedral angle between the heterocycle and the adjacent phenyl ring is 3.75 (15)°.

A review of synthetic methodologies reported in the last five years that yield N-heterocyclic products by intramolecular cyclization of organic azides with a particular emphasis on transformations catalyzed by metal complexes is presented. These reactions have been classified according to the ring size of the formed heterocycle.

In the title compound, C14H19N3O2, the heterocycle adopts a (1)C4 conformation with the N atom being one of the flap atoms. In the crystal, classical N-H⋯O hydrogen bonds and C-H⋯O contacts connect the mol-ecules into a three-dimensional network.

In the title compound, C28H30N2O2, the piperidine ring exists in a chair conformation with an equatorial orientation of the phenyl rings and methyl group substituted on the heterocycle. In the crystal, C-H⋯π inter-actions result in chains of mol-ecules running parallel to the a-axis direction.