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.

Synthesis, Molecular Docking, Dynamics, Quantum-Chemical Computation, and Antimicrobial Activity Studies of Some New Benzimidazole–Thiadiazole Hybrids

“…The proposed mechanism for the reaction of ester derivative compound 2 with hydrazine hydrate to give 3 is given in Figure 4. 29 The hydrazide derivative compound and the appropriate isothiocyanate derivatives in ethanol were refluxed, and the precipitated products were filtered off. In the last step, the thiadiazole derivatives 5a−h were obtained by cyclization of the thiosemicarbazide compound in the presence of concentrated sulfuric acid.…”

Synthesis, Characterization and Study the Biological Activity of New Morpholine Derivative

“…The solvent (DMSO) was used as a negative control while ciprofloxacin (10µg/disc)was used as a positive control , plates were incubated at 37 0 C for 18-24 hr [12]. The area of inhibition of zone was measured .Compound (10)(11)(12)(13)(14) showed good antibacterial activity .The antifungal activity was tested against the fungal species Candida at 150ppm concentration. The antifungal data revealed the compounds (10)(11)(12)(13)(14) to be moderately active against the fungi.…”

“…The compounds [3][4][5][6][7][8][9] were synthesized from the reaction between compound [2] and different substituted aromatic aldehydes/ketones in absolute ethanol and glacial acetic acid resulted in the formation of Schiff's bases [14,15] .as shown in following scheme 4: [3][4][5][6][7][8][9] in the next steps cyclized by treatment with chloro acetyl chloride followed by the addition of triethyl amine to give β-Lactam (10-14) [16] , as shown in the following scheme 5 :…”

Solvent-Free Ring Cleavage Hydrazinolysis of Certain Biginelli Pyrimidines

“…Recently, we reported a unique behavior of hydrazine hydrate towards certain benzofurans to produce phenolicbased pyrazoles [42]. We also identified malonohydrazide as reaction product besides salicylaldehyde azine upon the reaction of ethyl 2-oxo-2H-chromene-3-carboxylate with hydrazine hydrate [43]. In the light of previous data and in continuation of our interest in the chemistry of hydrazine hydrate towards certain heterocycles [44][45][46][47][48], we aim herein to study the solvent-free reaction of hydrazine hydrate on C5 ester Biginelli pyrimidines a-h (Figure 3).…”