Aldeídos e cetonas são intermediários importantes principalmente na construção de esqueletos carbônicos. A oxidação de álcoois é tão importante que um grande número de métodos e reagentes foi relatado com essa proposta. Reagentes N-halo são amplamente utilizados em síntese inorgânica e como continuação do nosso interesse na aplicação de compostos N-halo em síntese inorgânica, dibromo dimetilidantoína (DBDMH) e dicloro dimetilidantoína (DCDMH) foram usados na oxidação de álcoois e nosso trabalho em andamento está baseado no desenvolvimento de protocolos de oxidação altamente eficientes. Observamos a oxidação de álcoois secundários com quantidades estequiométricas de DBDMH e DCDMH em condições livre de solventes, na faixa de temperatura de 70-80 ºC.

Aldehydes and ketones are important intermediates, especially for the construction of carbon-skeletons. The oxidation of alcohols is so important that a large number of methods and reagents have been reported for this purpose. N-halo reagents are widely used in organic synthesis and as a continuation of our interest in the application of N-halo compounds in organic synthesis, dibromo dimethylhydantoin (DBDMH) and dichloro dimethylhydantoin (DCDMH) were used for the oxidation of alcohols and our ongoing work on development of highly efficient oxidation protocols. We observed the oxidation of secondary alcohols with stoichiometric amounts of DBDMH and DCDMH under solvent-free conditions in the range of temperature 70-80 ºC.

Sistemas de liberação de fármacos baseados em conjugados polímero-fármaco fornecem um tratamento melhorado com menor toxidade ou efeitos colaterais e são usados no tratamento de diferentes doenças. Conjugados de poli(estireno-alt-anidrido maleico) (PSMA) biodegradável, com agentes terapêuticos tais como cloridrato de amantadina, amlopidina, gabapentina, zonisamida e mesalamina, foram gerados pela formação de ligações de amidas dos fármacos amino que reagiram com os grupos anidridos do PSMA. As quantidades de fármacos covalentemente conjugados foram determinadas por ressonância magnética nuclear (NMR) de¹ H, e a taxa de liberação in vitro em solução tampão (pH 1.3) foi estudada à temperatura do corpo (37 ºC). Em estudos de cinética, modelos de dissolução diferentes foram examinados a fim de se obter dados de liberação do fármaco e os dados coletados se ajustaram bem a equação de Korsmeyer-Peppas, revelando um mecanismo de difusão Fickaniano dominante na liberação do fármaco em condições in vitro.

Drug delivery systems based on polymer-drug conjugates give an improved treatment with lower toxicity or side effects and be used for the treatment of different diseases. Conjugates of biodegradable poly(styrene-alt-maleic anhydride) (PSMA), with a therapeutic agents such as amantadine hydrochloride, amlodipine, gabapentin, zonisamide and mesalamine, were afforded by the formation of the amide bonds of the amino drugs that reacted with the PSMA anhydride groups. The amounts of covalently conjugated drugs were determined by a¹ H NMR spectroscopic method, and the in vitro release rate in buffer solution (pH 1.3) was studied at body temperature 37 ºC. In kinetic studies, different dissolution models were examined to obtain drug release data and the collected data were well-fitted to the Korsmeyer-Peppas equation, revealing a dominant Fickian diffusion mechanism for drug release under the in vitro conditions.

An efficient and simple solvent-free procedure for the synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[α]-xanthen-11-one derivatives via the one-pot multi-component condensation of dimedone with aromatic aldehydes and β-naphthol in the presence of protic acidic ionic liquid pyrazinium di(hydrogen sulfate) {Py(HSO4)2} as a green and homogeneous catalyst is described. All reactions proceed efficiently, and the title compounds are produced in high yields and in short reaction times.

Se describe un procedimiento simple y eficiente para la síntesis de derivados de 12-aril-8,9,10,12-tetrahidrobenzo[α]-xanten-11-ona mediante la condensación de multicomponentes en un solo paso de dimedona con aldehidos aromáticos y β-nafthol en presencia del líquido iónico ácido di(sulfato ácido) de pirazonio [Py(HSO4)2] como catalizador homogéneo y verde. Todas las reacciones procedieron eficientemente en tiempos cortos de reacción.

A highly efficient procedure for the synthesis of triarylmethane and diarylmethane via benzylation of aromatic hydrocarbons from benzyl alcohols using supported P2O5 on SiO2 and/or Al2O3 under solvent-free conditions is described. Excellent yields of triarylmethane and diarylmethane were obtained using P2O5-SiO2 (50 % W/W) and/or P2O5-Al2O3 (50 % W/W) at room temperature. The reusability of both supported P2O5 on SiO2 and Al2O3 were examined. Both supported reagents show favorable activities in first and second runs, however, a decline in reactivity was observed in following attempts. The reaction is scalable to >0.03 mole amounts.

Efficient oxidation of various types of structurally diverse alcohols to the corresponding carbonyl compounds can be carried out with N, N,-dibromo-N, N,-1,2-ethanediylbis(benzenesulphonamide) in good to high yield of products in CH2Cl2 at room temperature. Primary (aliphatic, benzylic and allylic) alcohols are oxidized with no over-oxidation to carboxylic acids.

Os ácidos 1-bromo-5,5-dietilbarbitúrico e 1,3-dibromo-5,5-dietilbarbitúrico foram preparados e usados na conversão de diferentes tipos de éteres de trimetilsilila aos correspondentes compostos carbonílicos em bons rendimentos, em diclorometano, à temperatura ambiente.

1-Bromo and 1,3-dibromo-5,5-diethylbarbituric acid were prepared and used for the conversion of different kinds of trimethylsilyl ethers to the corresponding carbonyl compounds in good yields in dichloromethane at room temperature.

Álcoois de estruturas diversas foram acetilados com anidrido acético, através de reações limpas e eficientes, usando-se quantidade catalítica de N,N-dicloro-4-metilbenzenossulfonamida em diclorometano. Todas as reações ocorreram a temperatura ambiente, com rendimentos de bons a excelentes.

Structurally diverse alcohols were acetylated in a clean and efficient reaction with acetic anhydride based on the use of a catalytic amount of N,N-dichloro-4-methylbenzenesulphonimide in dichloromethane. All reactions were performed at room temperature in good to excellent yields.

Um método novo e seletivo para clivagem de oximas envolve a reação das oximas derivadas de aldeídos e cetonas com N-bromoftalimida (NBPI) em acetona sob irradiação de microondas.

A new and selective method for the cleavage of oximes has been achieved by a simple reaction of a ketoxime or an aldoxime with N-bromophthalimide (NBPI) in acetone under microwave irradiations.