New Syntheses of Substituted Pyridazin-6-Ones and Pyridazin-6-Imines

Behbehani, Haider; Abdelkhalik, Mervat Mohammed; Elnagdi, Μ. H.

doi:10.1080/00304949909355339

Cited by 30 publications

(17 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is proposed that when Ac 2 O is present the glycine is acetylated to N-acetylglycine and then this compound cyclizes to form 2-methyloxazol-5-one (15a) and the latter in turn condensed with the arylhydrazone derivatives 6a,b,d-f,h to form the intermediate 16 which cannot be isolated, but then rearranges to form pyridazinone derivatives 17a-f. Similarly hippuric acid cyclized in the presence of Ac 2 O to give 5-phenyloxazol-5-one (15a) and then this compound condensed with arylhydrazone derivative 6a to gave pyridazinone derivative 17g [28,29]. Recently Elnagdi et al [10,30,31] have described a synthesis of pyridazine-5,6-dicarbonates 22a,b via reaction of 6b,e with dimethyl acetylenedicarboxylate in the presence of diphenylphosphine.…”

Section: Resultsmentioning

confidence: 99%

Microwave Assisted Condensation Reactions of 2-Aryl Hydrazonopropanals with Nucleophilic Reagents and Dimethyl Acetylenedicarboxylate

Al‐Zaydi

Borik

2007

Molecules

View full text Add to dashboard Cite

Abstract:The reaction of methyl ketones 1a-g with dimethylformamide dimethylacetal (DMFDMA) afforded the enaminones 2a-g, which were coupled with diazotized aromatic amines 3a,b to give the corresponding aryl hydrazones 6a-h. Condensation of compounds 6a-h with some aromatic heterocyclic amines afforded iminoarylhydrazones 9a-m. Enaminoazo compounds 12a,b could be obtained from condensation of 6c with secondary amines. The reaction of 6e,h with benzotriazolylacetone yielded 14a,b. Also, the reaction of 6a,b,d-f,h with glycine and hippuric acid in acetic anhydride afforded pyridazinone derivatives 17a-f. Synthesis of pyridazine carboxylic acid derivatives 22a,b from the reaction of 6b,e with dimethyl acetylenedicarboxylate (DMAD) in the presence of triphenylphosphine at room temperature is also reported. Most of these reactions were conducted under irradiation in a microwave oven in the absence of solvent in an attempt to improve the product yields and to reduce the reaction times.

show abstract

Section: Resultsmentioning

confidence: 99%

Microwave Assisted Condensation Reactions of 2-Aryl Hydrazonopropanals with Nucleophilic Reagents and Dimethyl Acetylenedicarboxylate

Al‐Zaydi

Borik

2007

Molecules

View full text Add to dashboard Cite

show abstract

“…2-Arylhydrazonoketones are readily obtained via condensation of arylhydrazines with 1,2-diketone [1,2] or via the coupling reaction of active methylene ketones with aromatic diazonium salts [3][4][5]. 2-Arylhydrazonals (1a) are prepared via coupling enaminones with aromatic diazonium salts, were shown to be excellent precursors to functionally substituted pyridazines [6][7][8], pyrazoles [9][10][11], and condensed azoles [12][13][14].In conjunction to our interest in chemistry of 2-arylhydrazonals 2b [8][9][10][11][12][13][14] as precursors to arylazoaminoazoles for potential utility in dye industry, we report here on the coupling reaction of the enaminonitriles 2b,c with aromatic diazonium salts and results of our investigation aimed at exploring synthetic potentials of these coupling products. The enaminonitrile derivative 2b needed in this investigation was prepared following literature procedure [15] (Figure 1).…”

mentioning

confidence: 99%

Synthesis and chemical reactivity of 3‐oxo‐2‐arylhydrazono‐propanenitriles

Abdallah

Metwally

Anwar

et al. 2005

Journal of Heterocyclic Chem

View full text Add to dashboard Cite

2-Formyl-2-arylhydrazonoethanenitriles 6b-d where prepared via reacting enaminonitrile 2b,c with aromatic diazonium salts. These reacted with phenylhydrazine to yield bis hydrazones that were converted to arylazopyrazoles via a novel Vilsmeier-Haack reaction type. Reaction of 6c with hydroxylamine afforded oxime that could be successfully cyclised into arylazoisoxazole. Reaction of 6c with hydrazine hydrate to yield arylazoaminopyrazole that proved to be excellent precursors for synthesis functional substituted pyrazolopyrimidines. 2-Arylhydrazonoketones are readily obtained via condensation of arylhydrazines with 1,2-diketone [1,2] or via the coupling reaction of active methylene ketones with aromatic diazonium salts [3][4][5]. 2-Arylhydrazonals (1a) are prepared via coupling enaminones with aromatic diazonium salts, were shown to be excellent precursors to functionally substituted pyridazines [6][7][8], pyrazoles [9][10][11], and condensed azoles [12][13][14].In conjunction to our interest in chemistry of 2-arylhydrazonals 2b [8][9][10][11][12][13][14] as precursors to arylazoaminoazoles for potential utility in dye industry, we report here on the coupling reaction of the enaminonitriles 2b,c with aromatic diazonium salts and results of our investigation aimed at exploring synthetic potentials of these coupling products. The enaminonitrile derivative 2b needed in this investigation was prepared following literature procedure [15] (Figure 1).The newly required enaminonitrile 2c was prepared in 73 % via reacting cyanoacetic acid with triethylorthoformate and piperidine or in better yield (80 %) via reacting 3-ethoxyacrylonitrile (3) with piperidine. 1 H-NMR indicate that the reaction product exists solely in the trans form as it indicated two olefinic protons at δ 4.0 and 7.1 with J = 13.5 Hz typical for trans olefinic protons. Appearance the olefinic proton of H-2 at δ 4.0 ppm is a result of shielding by electron donation from lone pair and cyano group anisotropy.We have found that coupling of 2b with aromatic diazonium salts affords either only formazanes 7 or mixtures of

show abstract

“…Although condensation reactions of arylhydrazonals with active methylene nitriles were originally reported to afford pyridazin-6-imines [6], more recent studies have demonstrated that arylazonicotinates are also formed in some of these processes [7][8][9]. Because arylazonicotinates are a valuable class of arylazopyridine dyes whose chemistry has attracted some interest as new disperse dyes [10][11][12], it seemed of value to undertake an investigation aimed at exploring the potential utility of arylhydrazonals as precursors for the preparation of these targets.…”

Section: Introductionmentioning

confidence: 99%

An efficient route for the synthesis of some monoazo disperse dyes derived from nicotinic acid derivatives

2013

View full text Add to dashboard Cite

KEYWORDSEthyl 2-amino-3-cyano-4-phenylnicotinates (8), could be readily synthesized via reacting ethyl propiolate with benzylidenemalononitrile in the presence of L-proline as a catalyst and subsequent rearrangement of the so formed 2-aminopyran (7), with acetic acid in the presence of ammonium acetate. A series of 2-amino and 2-hydroxyarylazonicotinates monoazo disperse dyes (12a-c), were prepared in a good yields via condensation of arylhydrazonals (11a-c), with active methylene nitriles. The compound 9 was also characterized by single crystal X-ray diffraction studies. Crystal data for compound 9, C15H18O6 (M = 294.29): hexagonal, space group P65 (no. 170), a = 11.3311 (5)

show abstract

New Syntheses of Substituted Pyridazin-6-Ones and Pyridazin-6-Imines

Cited by 30 publications

References 10 publications

Microwave Assisted Condensation Reactions of 2-Aryl Hydrazonopropanals with Nucleophilic Reagents and Dimethyl Acetylenedicarboxylate

Microwave Assisted Condensation Reactions of 2-Aryl Hydrazonopropanals with Nucleophilic Reagents and Dimethyl Acetylenedicarboxylate

Synthesis and chemical reactivity of 3‐oxo‐2‐arylhydrazono‐propanenitriles

An efficient route for the synthesis of some monoazo disperse dyes derived from nicotinic acid derivatives

Contact Info

Product

Resources

About