Synthesis of 5H-pyrido[4,3-b]indole by a modification of Pomeranz-Fritsch isoquinoline synthesis.

5H-Pyrido[4,3-b]indole was obtained from 3-formylindole in 16% overall yield by Jackson and Shannon modification of the Pomeranz-Fristch isoquinoline synthesis. The final cyclisation occurred but the removal of the tosyl group and oxidation of the dihydrocompound was not efficient. Changes in the concentration of the acid catalyst gave 29% as the best yield for the last step. An NMR study of the cyclisation is described.Fundação para a Ciência e Tecnologia (FCT) and FEDE

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

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

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 and characterization of psoralen analogues based on carbazoles

Novel psoralen analogues based on carbazoles were synthesized and characterized.Fundação para a Ciência e Tecnologia (FCT) and FEDER, for National NMR Networ

Synthesis and characterization of psoralen analogues based on dibenzofuran

Fundação para a Ciência e Tecnologia (FCT) and FEDER, for National NMR Networ

Photodegradation studies on C. I. reactive red 158

Dye-containing wastewater generated from textile industries is a major source of environmental pollution. Azo dyes, which are the largest group of coloring agents, are widely used in industry. Advanced Oxidative Processes are very promising for effluent treatment mainly due to their high efficiency and simplicity of operation. Our group became interested on photocatalytic methods (included in the AOP’s), using TiO2, for degradation of dyes, started with simpler structures and continued with commercial dyes. Titanium dioxide (TiO2) has proven to be the most effective and suitable catalyst for photocatalytic reaction due to its low cost economical, chemical stability, and insolubility. In this paper, the effects of UV light irradiation in the presence of TiO2 particles at various pH’s (3, 6, 8 and 10) on the photodegradation of an azo dye, Reactive Red 158, were investigated. The photocatalytic degradation was carried out either in aqueous solutions or in a synthetically prepared dyebath effluent, under UV irradiation, in the presence of Degussa P25 TiO2 as the catalyst. Reactive dyes of the pyrimidinyl type partly hydrolyse during dyeing in basic medium; RR 158 was hydrolysed and this solution was also irradiated. The fastest degradation was obtained with an acid solution (14 minutes, 95.53% loss of colour), but the hydrolysed dye took longer to be decolourised

Alternative products to carbazoles in the oxidation of diphenylamines with palladium (II) acetate

Although simple diphenylamines are conveniently oxidised with Palladium (II) acetate to give carbazoles, for more complex examples, carbazoles are minor products amongst many.CRUP (Portugal). British Council - Treaty of Windsor Programme. Junta Nacional de Investigação Científica e Tecnológica

Studies on the reaction of morita-baylis-hillman with indole and carbazole derivatives

Fundação para a Ciência e a Tecnologia (FCT)and FEDE

Thermal analysis of a polymorphic azo dye derived from 2-amino-5-nitrothiazole

An azo dye, derived from 2-amino-5-nitrothiazole and a substituted N,N-dimethyl aniline, was studied by various techniques. Two sets of proton signals were obtained by NMR in CDCl3 solution, suggesting that two polymorphs coexist, however only one set of signals is observed in DMSO solution. Differential scanning calorimetry and thermogravimetric analysis were used to confirm the existence of two forms. The events registered during thermal treatment of a sample were assigned to a glass transition, recrystallization and fusion of crystalline compounds. Hot-stage microscopy was used to obtain images of the dye samples at various stages of the heating program and these observations support the interpretation of the calorimetric results.Fundação para a Ciência e a Tecnologia (FCT