O ácido bórico foi usado neste trabalho como um catalisador "verde", seletivo e reciclável, para a trimetilsililação de álcoois e fenóis usando hexametildissilazano em acetonitrila. A desproteção de trimetilsililéteres para regenerar seus alcoóis e fenóis precursores foi também realizada usando este catalisador em água à temperatura ambiente. As características de destaque desta metodologia são o baixo custo do processo, as condições brandas de acidez, os rendimentos excelentes e a disponibilidade ampla do catalisador.

Boric acid has been used as a green, selective and recyclable catalyst for trimethysilylation of alcohols and phenols using hexamethyldisilazane in acetonitrile. Deprotection of trimethylsilyl ethers to their parent alcohols and phenols was also achieved using this catalyst in water at room temperature. The salient features of this methodology are cheap processing, mild acidity conditions, excellent yields of products and easy availability of the catalyst.

N-Bromosuccinimide (NBS) catalyses the ring opening of various epoxides with different thiols in CH3CN at room temperature under mild reaction conditions. The corresponding β-hydroxysulphides are obtained in short reaction times and in good to high yields with nearly complete regioselectivity. The catalyst was compared with previously reported catalysts and only one that we have found [B(C6F5)3] gave the same regioselectivity, but the reaction time was much longer (4 h versus 5 min) and the yield was considerably lower. Zn(ClO4)2.6H2O gave slightly lower selectivity but higher yields. The reaction time was about 12 times longer.

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.