3-Aminopyrroles and their application in the synthesis ofpyrrolo[3,2-d]pyrimidine (9-deazapurine) derivatives

3-Aminopyrrole derivatives have been synthesized from 3-anilino-2-cyanoacrylonitrile using Thorpe-Ziegler cyclization. These substituted pyrroles are readily converted into 5H-pyrrolo[3,2- d]pyrimidine (9-deazapurines).FEDERFundação para a Ciência e Tecnologia (FCT

Heterocyclic synthesis with nitriles: synthesis of pyridazine and pyridopyridazine derivatives

The reaction of MND with aryldiazonium chlorides followed by cyclization afforded the pyridazinimine derivatives. Reaction of the latter with another mole of malononitrile produce only pyrido[3,2-c]pyridazine derivatives. Reaction of 4-aminopyridazinone-3- carboxylic acid esters with malononitrile gave only pyridazine-3-carboxylic acid.Fundação para a Ciência e a Tecnologia (FCT) - POCTI-SFA-3-686, SFRH/BPD/31490/2006Fundo Europeu de Desenvolvimento Regional (FEDER

Synthesis of some novel pyrazolo[3,4-d]pyrimidine derivatives

Reaction of ethyl imidates derived from N-aryl-5-amino-4-cyanopyrazoles with amines or arylhydrazines gave only 4-substituted pyrazolo[3,4-d]pyrimidines, resulting from cyclization followed by Dimroth rearrangement. From the reaction with arylhydrazines, a mixture of the hydrazines and their oxidized forms, the azo products, was obtained. This was proven by an independent synthesis starting from the corresponding 4-chloropyrazolo[3,4-d]pyrimidines as starting material. The structures of the compounds obtained were confirmed by mass spectrometry, 1H and 13C NMR.Fundação para a Ciência e Tecnologia (FCT) - POCTI-SFA-3-686, SFRH/BPD/31490/2006FEDE

Synthesis of 3-indolylazoles and meridianin derivatives from indolyl enaminonitriles

The reaction of indole derivatives with cyanoacetic acid followed by treatment with DMFDMA gave the intermediate indolyl enaminonitriles (3). Further reaction with aminoguanidine yielded 5´-cyanomeridianin analogues (4). The same intermediate reacted with p-methoxyphenylhydrazine to give the pyrazolyl derivative (8). Treatment of (2E)-3-dimethylamino-2-(1H-indol-3-yl)-propenoate (3a) with hydroxylamine hydrochloride in basic medium afforded (5-amino-isoxazol-4-yl)-(1H-indol-3-yl)-methanone (5) and the acrylic acid derivative (6) after a short or a long heating, respectively. Unequivocal structural elucidation of the latter compound was achieved from single-crystal X-ray diffraction studies.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BPD/31490/2006FEDER - REEQ/ 630/QUI/200

Synthesis of tacrine analogues derived from n-aryl-5-amino-4-cyanopyrazoles

Synthesis of eleven tacrine analogues derived from N-aryl-5-amino-4-cyanopyrazoles, by a Friedländer type reaction, is described. Their structures were confirmed by 1H and 13C NMR spectroscopy, elemental analysis and/or mass spectrometry.Fundação para a Ciência e Tecnologia and FEDER (POCTI-SFA-3-686

Heterocyclic synthesis with nitriles: synthesis of pyrazolopyrimidine and pyrazolopyridine derivatives

The reaction of N1-substituted-5-amino-4-cyanopyrazoles with malononitrile and diethylmalonate occurs with formation of 6-substituted pyrazolo[3,4-d]pyrimidines, and pyrazolo[3,4-b]pyridines respectively. The structures of the products and conceivable mechanisms are discussed.Fundação para a Ciência e Tecnologia - SFRH/BPD/31490/2006Fundo Europeu de Desenvolvimento Regional (FEDER) - POCTI-SFA-3-68

Cyanoacetylation of 5-Aminopyrazole: Synthesis of 2-(1-Aryl-4-substituted pyrazolo[3,4-d]pyrimidin-6-yl)acetonitrile Derivatives Z

N1 -cyanopyrazoles were cyanoacetylated with a mixture of cyanoacetic acid and acetic anhydride. Cyclization with POCl 3 gave 4-chloro-pyrazolo[3,4-d]pyrimidine derivatives. From the reaction with hydrazine and arylhydrazines, the hydrazinyls and their oxidized forms, the azo products, were obtained. The structure of the compounds obtained has been confirmed by 1 H and 13 C NMR spectroscopy