Reactions with the Arylhydrazones of α‐Cyanoketones: The Structure of 2‐Arylhydrazono‐3‐ketimino‐nitriles

Abstract

Analysis of the IR., UV., and polarographic data of a variety of 2‐arylhydrazono‐3‐ketimino‐nitriles indicated that these derivatives exist mainly in the intramolecularly chelated hydrazone structure 1. Compounds 1 reacted with hydrazine hydrate to yield the corresponding 5‐amino‐4‐arylazopyrazoles (3). Compounds 3a reacted with acetylacetone, ethyl acetoacetate, and diethyl malonate to yield the pyrazolo[1, 5‐a]pyrimidine derivatives 4, 5, and 7 respectively. Compound 3a also reacted with benzoylisothiocyanate to yield the pyrazolyl thiourea derivative 8.

Formation of methyl 2-arylhydrazono-3-oxobutanoates and 2-arylhydrazono-3-oxobutanenitriles during the coupling reaction of arenediazonium ions with methyl 3-aminocrotonate and 3-aminocrotononitrile

“…In more recent work, Elnagdi et al (9) reported further synthetic applications of the 2-arylhydrazono-3-ketiminobutanenitrile ( l l ) , which is formally the deprotonated form of the hydrazone tautomer of the intermediate (7) The reaction of aryldiazonium salts with carbanions of Pin our proposed mechanism (Scheme 1). dicarbonyl compounds has been reported by several workers…”

Synthesis of a new triheterocycle. Bis-pyrazolo[1,5-a][4',3'-e]pyrimidine

“…The required 2,7-dimethyl-8-phenylazo-4(6H)-pyrazolo[1,5-a]pyrimidinone 1 was prepared by reaction of ethyl acetoacetate with 5-amino-4-arylazo-3-methyl-1H-pyrazole as previously described. 28 As no spectral data were reported for compound 1, we wish to report herein its IR, 1 H-and 13 C-NMR as well as the UV and mass spectral data (see Experimental). For example, the IR spectrum of compound 1 revealed one carbonyl band and one NH band at υ 1674 and 3228 cm -1 , respectively.…”

Synthesis, antimicrobial activity and absorption studies of some novel heterocyclic dyes based on 4-hexylbenzene-1,3-diol

“…Elemental analysis was done on a Perkin Elmer CHNS/O Analyzer 2400 Series II were recorded on Agilent 1100 MSD. 2-Arylhydrazone-3-ketiminobutyronitriles (1a-1j) and 5-amino-4-arylazo-3-methyl-1H-pyrazoles (2a-2j) were prepared according to the literature procedures [1,2]. The general route for the synthesis of 2-arylhydrazono-3-ketiminobutyronitriles and 5-amino-4-arylazo-3-methyl-1H-pyrazoles is shown in (Scheme 1).…”

“…The other λmax values of 3101-3022 cm -1 (aromatic C-H) and 2994-2963 cm -1 (aliphatic C-H) were recorded. 1 H NMR spectra of dyes 5a-5j showed four broad peaks at 12.75-10.23 ppm (NH), 11.20-9.30 ppm (NH) and two broad peaks at 7.9-8.9 ppm (OH), 10.5-11.2 ppm (OH), 0.86-0.96 ppm (CH3), 1.24-1.89 ppm (CH2), respectively. The other δ values of 2.48-2.40 ppm (CH3) and 8.35-6.98 ppm (aromatic H) were recorded.…”

“…The usage of many pyrazole derivatives has undoubtedly created considerable attention in developing many different synthetic procedures in pharmaceuticals, agrochemicals, dyestuff. The recent developments in the synthetic routes and the chemistry of pyrazoles have been thoroughly reviewed [1][2][3][4][5]. The condensation of β-enaminonitriles and β-ketoesters with hydrazines continues to be the most widely used method for constructing the aminopyrazoles and pyrazolones, respectively [6,7].…”