[reaction: see text] The one-pot synthesis of new 9-alkyl-6-chloropyrido[3,2-e][1,2,4]triazolo[4,3-a]pyrazines has been achieved. Hydrazides regioselectively reacted as nucleophiles with the 3-chloro substituent of 2,3-dichloropyrido[2,3-b]pyrazine. An intramolecular cyclization afforded the tricycle nonxanthine adenosine receptor antagonists.

A copper-catalyzed domino protocol for the synthesis of 2-(1,3,4-oxadiazol-2-yl)aniline derivatives has been developed from simple and available isatins and hydrazides. This domino process integrated consecutive condensation, base-promoted ring-opening and the key copper-catalyzed decarboxylative coupling for intramolecular C-O bond formation.

The reaction of acid hydrazides (1a-c) with 2-chloro-1-(4-chlorophenyl)ethanone (2a) or 2-bromo-1-(4-bromophenyl)ethanone (2b) afforded bis-hydrazones 6a-d, while the reaction of la-c with 2-oxo-N-arylpropanehydrazonoyl chlorides (3a,b) furnished N-(aryl)propanehydrazonoyl chlorides 8a-c. The reaction of the latter chlorides with sodium benzenesulfinate furnished sulfones 11a-c. On the other ha...

A catalytic bicyclization reaction of 1,5-enynes anchored by α,β-conjugates with arylsulfonyl radicals generated in situ from sulfonyl hydrazides has been established using TBAI (20 mol%) and Cu(OAc)2 (5 mol%) as co-catalysts under convenient conditions. In addition, the use of benzoyl peroxide (BPO) as the oxidant and pivalic acid (PivOH) as an additive was proven to be necessary for this reac...

The title compound, C(16)H(17)N(3)O(2), was synthesized by the reaction of 4-dimethyl-amino-benzaldehyde with 3-hydroxy-benzoic acid hydrazide in methanol. The dihedral angle between the two benzene rings in the mol-ecule is 9.2 (2)°. In the crystal structure, mol-ecules are linked through inter-molecular O-H⋯O, O-H⋯N and N-H⋯O hydrogen bonds, forming layers parallel to the bc plane.

Facile reactivity of hydrazides and aldehydes was explored as potential coupling partners for incorporation into M(CO)(3) (M = Re, (99m)Tc) based radiopharmaceuticals. Both 'click, then chelate' and 'prelabel, then click' synthetic routes produced identical products in high yields and lacked metal-hydrazide/-hydrazone interactions, highlighting the potential of this click strategy.

A new cascade three-component halosulfonylation of 1,7-enynes for efficient synthesis of densely functionalized 3,4-dihydroquinolin-2(1H)-ones has been established from readily accessible arylsulfonyl hydrazides and NIS (or NBS). The reaction pathway involves in situ-generated sulfonyl radical-triggered α,β-conjugated addition/6-exo-dig cyclization/radical coupling sequence, resulting in contin...