title: The reaction of ethyl 2-oxo-2H-chromene-3-carboxylate with hydrazine hydrate.
abstract: Although salicylaldehyde azine (3) was reported in 1985 as the single product of the reaction of ethyl 2-oxo-2H-chromene-3-carboxylate (1) with hydrazine hydrate, we identified another main reaction product, besides 3, which was identified as  malono-hydrazide (4). In the last two decades, however, some articles have claimed that this reaction afforded exclusively hydrazide 2 and they have reported the use of this hydrazide 2 as a precursor in the syntheses of several heterocyclic compounds and hydrazones 6. We reported herein a study of the formation of 2 and a facile route for the synthesis of the target compounds N'-arylidene-2-oxo-2H-chromene-3-carbohydrazides 6a-f.
authors: Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia. hatem_741@yahoo.com
authors: Hatem A
authors: HA
authors: Abdel-Aziz
authors: Tilal
authors: T
authors: Elsaman
authors: Mohamed I
authors: MI
authors: Attia
authors: Amer M
authors: AM
authors: Alanazi
mesh_terms: D003374:Coumarins / Q000138:chemical synthesis / Q000737:chemistry*; D004952:Esters / Q000737:chemistry; D006834:Hydrazines / Q000737:chemistry*; D006835:Hydrazones / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D003374:Coumarins; D004952:Esters; D006834:Hydrazines; D006835:Hydrazones; C550929:ethyl 2-oxo-2H-chromene-3-carboxylate; C029424:hydrazine
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