Studies on 3-oxoalkanenitriles: novel rearrangement reactions observed in studies of the chemistry of 3-heteroaroyl-3-oxoalkanenitriles as novel routes to 2-dialkylaminopyridines.
TL;DR: 3-Aroyl and 3-heteroaroyl substituted 3-oxoalkanenitriles were synthesized by the reactions of activated aromatic and hetero-aromatic substances with cyanoacetic acid in the presence of acetic anhydride and were observed to undergo condensation reactions with dimethylformamide dimethyl acetal to afford the corresponding enamino-nitriles.
Abstract: 3-Aroyl and 3-heteroaroyl substituted 3-oxoalkanenitriles were synthesized by the reactions of activated aromatic and hetero-aromatic substances with cyanoacetic acid in the presence of acetic anhydride. As part of studies focusing on the preparation of cyanoacetyl-1-N-methylbenzimidazole, we observed that reaction of N-methyl-benzimidazole with the cyanoanhydride formed by condensation of cyanoacetic acid with acetic anhydride, leads to the formation of 2-(1,3-diacetyl-2,3-dihydro-1H-benzo[d]-imidazol-2-yl)acetonitrile (5), whose structure was confirmed by X-ray crystallographic analysis. 3-Oxoalkanenitriles 3a,b were observed to undergo condensation reactions with dimethylformamide dimethyl acetal (DMFDMA) to afford the corresponding enamino-nitriles, which react with malononitrile to give 2-dialkylaminopyridines through a pathway involving a new, unexpected rearrangement process. Reactions of 3-oxoalkanenitriles with ethyl acetoacetate were found to afford 2-oxopyran-3-carbonitriles, also occurring via this unexpected rearrangement process. Mechanisms to account for both rearrangement reactions are suggested. In addition, reactions of 3-oxoalkanenitriles with acetylacetone in acetic acid in the presence of ammonium acetate result in the formation of pyridine-3-carbonitriles. Finally, upon heating in the presence of zeolite 3-oxoalkanenitriles 3b,c self-trimerized to produce the corresponding aniline derivatives 23b,c.
Citations
More filters
TL;DR: Polymeric catalysts could be used instead of the old toxic commercial organic basic catalysts, piperidine or pyridine, and could be readily isolated from the reaction mixture and recycled several times without significant loss of catalytic activity.
Abstract: Chitosan-grafted-poly(4-vinylpyridine) (Cs-PVP) copolymers could be synthesized under heterogeneous conditions in presence of a potassium persulfate and sodium sulfite redox system. The synthesized graft copolymer could be utilized effectively, in the form of beads, as an efficient catalyst for Michael additions of active methylenes to functionally substituted alkenes. Moreover, methyl moiety oxidation in methyl pyridazinyl carbonitriles by H2O2 in the presence of chitosan-g-polyvinyl pyridine–supported iron (III) complex, Cs-PVP/Fe, could be affected. A variety of pyrans, naphthopyrans, and thiopyrans could be synthesized efficiently in the presence of these graft copolymer beads by novel catalytic routes. These polymeric catalysts could be used instead of the old toxic commercial organic basic catalysts, piperidine or pyridine, and could be readily isolated from the reaction mixture and recycled several times without significant loss of catalytic activity.
40 citations
Cites background from "Studies on 3-oxoalkanenitriles: nov..."
...Some time ago the formation of dieneamide 15a via reaction of enaminone 14a with malononitrile has been reported from our laboratories [37,38]....
[...]
TL;DR: The results of the catalytic studies demonstrated that Cs-g-PCPA serves as an efficient, recyclable and eco-friendly, basic catalyst for Michael addition reactions, which produce adducts in high yields under mild conditions.
20 citations
TL;DR: A literature survey of antipyrine, considered as one of the most valuable compounds in the fields of organic and medicinal chemistry, is presented in this paper, where the biological importance, synthetic procedures, and reactions are discussed.
19 citations
TL;DR: In this article, 2-thioxothiazole derivatives 5a-c were prepared by reacting a mixture of 1a c, CS2/KOH and 4-(2-chloroacetyl)-1, 5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one(3).
Abstract: 2-Thioxothiazole derivatives 5a-c were prepared by reacting a mixture of 1a-c, CS2/KOH and 4-(2-chloroacetyl)-1, 5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one(3). Reacting 2-cyano-N-(4-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-2H- pyrazol-4-yl)-2-thioxothiazol-3(2H)-yl)acetamide (5c) with mercaptoacetic acid, arylidenemalononitriles 8 and (E)- 3-(dimethylamino)-1-(furan-2-yl)prop-2-en-1-one (12) give 4-oxo-4,5-dihydrothiazole 6, 2-oxo-1,2-dihydropyridine 10 and 2-oxo-2H-pyran 15 respectively. Heating a mixture of 5c, malononitrile and elemental sulfur yield 2,4-diaminothio- phene 19. Coupling of 5c with the diazotized aminopyrazole 20 and aryldiazonium salts 23 give pyrazolo[5,1-c][1,2,4] triazines 22 and arylhydrazones 25 respectively.
9 citations
Cites background from "Studies on 3-oxoalkanenitriles: nov..."
...These pharmacological activities have been attracted special attention to prepare a new class of thiazole derivatives carrying antipyrinyl moiety because of their applications in the field of pharmaceuticals [4-6] and antibacterials [7-9]....
[...]
TL;DR: The reaction of 3-oxo-3-phenyl-2-phenelhydrazonal with functionally substituted and heteroaromatic substituted acetonitrile to yield arylazonicotinic acid derivatives and 5-arylsubstituted pyridines was established.
Abstract: The reaction of 3-oxo-3-phenyl-2-phenylhydrazonal with functionally substituted and heteroaromatic substituted acetonitrile to yield arylazonicotinic acid derivatives and 5-arylsubstituted pyridines was established. In some cases the produced nicotinates could not be isolated as they underwent thermally induced 6π-electrocyclization yielding polynuclear pyridine derivatives.
9 citations
References
More filters
TL;DR: A novel synthesis of 4-oxo-4H-pyrano[2,3-c]pyrazole could be achieved via reacting 3-methyl-2-pyrazolin-5-one with a mixture of cyanoacetic acid and acetic anhydride.
Abstract: Pyrano[2,3-c]pyrazoles are obtained via mixing ethyl acetoacetate, hydrazine hydrate, aldehydes or ketones and malononitrile in the absence of solvent. These same products were also obtained by reacting arylidenemalononitriles 3 with 3-methyl-2-pyrazolin-5-ones. NOE difference experiments confirmed that these products exist solely in the 2H form. Similar treatments of 3-amino-2-pyrazolin-5-one with arylidene-malononitrile afforded adduct 6. Similarly mixing ethyl cyanoacetate, hydrazine hydrate, aldehydes, with malononitrile gave the same product 6. A novel synthesis of 4-oxo-4H-pyrano[2,3-c]pyrazole (8) could be achieved via reacting 3-methyl-2-pyrazolin-5-one with a mixture of cyanoacetic acid and acetic anhydride. Similar treatment of 3-aminopyrazole 11 with the benzylidene-malononitrile produced the pyrazolo[2,3-a]pyrimidines 12a,b.
79 citations
TL;DR: In this paper, des intermediaires importants pour la synthese d'une variete de systemes heterocycliques difficilement accessible par d'autres methodes.
Abstract: Revue des methodes de preparation, des etudes structurales et de la reactivite des oxo-3 alcanenitriles. Ces composes sont des intermediaires importants pour la synthese d'une variete de systemes heterocycliques difficilement accessibles par d'autres methodes
51 citations
TL;DR: In this paper, arylidene derivatives of benzoylacetonitrile were cycled into 2-phenyl-4,5,6,7,7-tetrahydropyrazolo[1,5-a]pyrimidin-5-one by acetic acid-hydrochloric acid.
43 citations
TL;DR: Cyanoacetic acid was activated with acetic anhydride and when heated this reagent reacted with a variety of both activated and deactivated pyrroles, indoles and aniline derivatives.
Abstract: Cyanoacetic acid was activated with acetic anhydride and when heated this reagent reacted with a variety of both activated and deactivated pyrroles, indoles and aniline derivatives.
41 citations
TL;DR: In this paper, the reaction of electron rich aromatics with cyanoacetic acid and acetic anhydride afforded 3-oxoalkanenitriles, which were subsequently condensed with dimethylformamide dimethylacetal (DMFDMA) to yield enaminones that reacted readily with hydrazine hydrate to yield 4-aroylpyrazole-3-amines.
40 citations