Abstract
Reaction of 2-pyridylcarboxamidrazone with D-arabinose, D-xylose, D-galactose, D-glucose and D-mannose afforded the corresponding hydrazones in either the acyclic or cyclic structures depending on the nature of the sugar. Assignment of the sugar hydrazones structures were based on 1D and 2D NMR experiments. Vicinal coupling constants were used to deduce the favored conformations.
Highlights
Amidrazones are important precursors for many useful compounds with industrial and medicinal applications.1 2-Pyridylcarboxamidrazone and its heterocyclic derivatives showed antimicrobacterial activity[2] and anticancer activity.[3]
Condensation of an equimolar amount of 2-pyridylcarboxamidrazone (1) with aldoses was carried out in refluxing ethanol to give the respective hydrazone derivatives 5, 6, 10, 11 and 12 accompanied with a yellow crystalline by-product, which was separated by fractional crystallization and identified from its spectral data; FABMS showed a molecular ion peak at m/z 240 as the dihydrazidine 2.12 the dihydrazidine 2 was formed when the amidrazone 1 was heated in a solution of ethanol and in the presence of oxygen
Sugar hydrazones can exist in solution as acyclic Schiff's base or as cyclic glycosylhydrazine[10,13,14] and are often present as equilibrium mixtures that are strongly dependent on the pH of the solution as well as on the nature of the sugar and the basicity of the hydrazine derivative
Summary
Amidrazones are important precursors for many useful compounds with industrial and medicinal applications.1 2-Pyridylcarboxamidrazone and its heterocyclic derivatives showed antimicrobacterial activity[2] and anticancer activity.[3] The phenylalanine derivative (S)-3-(4amidrazonophenyl)-N-cyclopentyl-N-methyl-2-(naphthalene-2-sulfonyl)propionamide (LB30057) was identified as a potent selective and orally active thrombin inhibitor; several derivatives have significant enhancing potency as thrombin inhibitors.[4] Carbohydrates have attracted much attention as starting material in organic synthesis.[5] Their role in the synthesis of naturally occurring nitrogen heterocycles[6] has been investigated in various laboratories. May lead to an interesting improvement in their biological activity and/or enhancement of their bioavailability as a consequence of the hydrophilic nature of the alditolyl residue that may aid in their transportation into biological systems
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