69081-08-9Relevant academic research and scientific papers
Synthesis of N- and C-azolyl-substituted pyrazolo[1,5-a]pyrimidines by recyclization of pyrimidinium salts
Danagulyan, Gevorg G.,Tumanyan, Araksya K.,Attaryan, Oganes S.,Tamazyan, Rafael A.,Danagulyan, Anna G.,Ayvazyan, Armen G.
, p. 483 - 490 (2015/10/19)
We studied the reaction of 2-(ethoxycarbonyl)methyl-1,4,6-trimethylpyrimidinium iodide with hydrazides of N-azolyl- and C-pyrazolyl-substituted carboxylic acids, which were synthesized by reacting the respective esters with hydrazine hydrate. This reaction was shown to result in recyclization and formation of ethyl 2-(pyrazolylalkyl)- and 2-(azolylalkyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidine- 3-carboxylates. Besides pyrazolopyrimidines, the separation of reaction mixture provided in some cases also another recyclization product, 2-hydroxy-5,7-dimethylpyrazolo[1,5-a]pyrimidine.
Intermediates in the transformation of 1,2-dialkylpyrimidinium iodides in the Kost-Sagitullin rearrangement
Danagulyan,Tadevosyan,Kinoyan
, p. 782 - 787 (2008/02/05)
Intermediate recyclization products were obtained in a study of the Kost-Sagitullin rearrangement of a series of 1,2-dialkylpyrimidinium iodides. The initial attack of the nucleophile leads to the formation of products of the addition of the hydroxyl group, namely, the corresponding pseudo bases. Heating one of these intermediates in ethanol or in the presence of primary amines leads to rearrangement to give a pyridone derivative. Upon heating in chloroform, the pseudo bases readily lose a water molecule and are converted to anhydro bases, namely, derivatives of 1-alkyl-1,2-dihydro-2-methylidenepyrimidine.
Novel route for the transformation of a pyrimidine ring using hydrazides
Danagulyan,Tadevosyan,Tamazyan,Panosyan
, p. 233 - 245 (2007/10/03)
It has been shown from X-ray structural analytical data that the reaction of 2-ethoxycarbonylmethyl-1,4,6-trimethylpyrimidinium iodide with carboxylic acid hydrazides gives pyrazolo[1,5-a]pyrimidine derivatives and not the isomeric triazolo[4,3-a]pyridines previously reported. This novel and previously unreported rearrangement of 1,2-dialkylpyrimidinium salts occurs via recyclization of the pyrimidine ring with inclusion of a fragment of the nucleophilic reagent into the transformation product. 2006 Springer Science+Business Media, Inc.
Synthesis of nicotinic acid derivatives by the reaction of salts of 1-alkyl-4,6-dimethyl-2-pyrimidinylacetic acid esters with amines
Danagulyan,Saakyan,Panosyan
, p. 323 - 328 (2007/10/03)
A study was carried out on the enamine rearrangement of iodoalkylates of the ethyl ester of 4,6-dimethyl-2-pyrimidinylacetic acid to give ethyl esters of 2-alkylamino-4,6-dimethylnicotinic acid, which proceeds upon the action of various amines. The reaction with amines containing an alkyl substituent different from that at the quaternized nitrogen atom of the pyrimidinium salt leads to the formation of products of rearrangement and transamination. In the presence of water, the rearrangement is accompanied by the formation of the ethyl ester of 1,2-dihydro-2-oxo-4,6-dimethylnicotinic acid.
Exchange aminations in conversions of pyrimidinium iodides to 2- alkylaminonicotinic acids
Danagulyan, Gevorg G.,Sahakyan, Larisa G.,Katritzky, Alan R.,Denisenko, Sergey N.
, p. 419 - 422 (2007/10/03)
1-Alkyl-2-(ethoxycarbonylmethyl)pyrimidinium iodides (1) are transformed into 2-alkylaminonicotinic acids (2) by reactions with aliphatic primary amines. Two alternative reaction paths are proposed, one of which involves exchange of the amine moieties.
