The acetalization or transacetalization reactions produce acetals or ketals used in cosmetics, food, pharmaceuticals, and fuel additives. Besides synthesizing several products, the acetalization or transacetalization reactions can protect carbonyl groups, 1,2 and 1,3-diols in multi-step synthesis. This work studies the transacetalization of glycerol with 2,2-dimethoxypropane (2,2-DMP) to yield 2,2-dimethyl-4-hydroxymethyl-1,3-dioxolane (solketal) by catalyzing with USY, HBeta, and HZSM-5 zeolites under cleaner and mild reaction conditions (reaction temperature: 25 °C; 2,2-DMP/glycerol molar ratio: 1; reaction time: 1 h; and catalyst concentration: 0.05-5 wt.%). For catalyst concentration equal to or greater than 2,5 wt.%, glycerol conversion stabilized near 96-97% for the three zeolites tested. The product selectivities also assume a constant value, close to 97% for solketal. For the lowest concentration of catalyst, the influence of the zeolite properties on the glycerol conversion, such as acidity and the strong/weak acid site ratio, was observed. Concerning the selectivity of the products, the results suggested that it can be based on zeolite topology, active sites at the particle surface, and the relative amount of micro and mesoporous HBeta, the most selective catalyst for acetals production, was reused at least once without loss of activity and selectivity. cosmetics food pharmaceuticals additives products groups 12 2 1, 1,3diols 13diols diols 1,3 3 multistep multi step synthesis 2,2dimethoxypropane 22dimethoxypropane dimethoxypropane 2,2 2,2DMP 22DMP DMP (2,2-DMP 2,2dimethyl4hydroxymethyl1,3dioxolane 22dimethyl4hydroxymethyl13dioxolane dimethylhydroxymethyldioxolane dimethyl 4 hydroxymethyl dioxolane solketal (solketal USY HBeta HZSM5 HZSM 5 HZSM- temperature °C C 2,2DMP/glycerol 22DMPglycerol DMPglycerol DMP/glycerol ratio time h 0.055 0055 0.05 0 05 0.05- wt.%. wt wt.% . wt.%) 2, 9697% 9697 96 97 96-97 tested value strongweak strong weak observed topology surface production 3diols 13 2dimethoxypropane 22 2DMP 2dimethyl4hydroxymethyl1 3dioxolane 055 005 0.0 wt. 969 9 96-9 dimethylhydroxymethyl 2dimethyl4hydroxymethyl 00 0. 96-

The ethers produced through the etherification reaction of glycerol with ethanol or t-butanol are used as oxygenated fuel additives, intermediates in the pharmaceutical industry, and non-ionic surfactants. However, the identification of these ethers has not been accurately done, because only some mass spectra of these compounds are available in the libraries. Moreover, there is a lack of discussion on their identification in the literature. In this work, a detailed identification of all ethers produced in the etherification of glycerol with ethanol or t-butanol was performed considering the mass spectra of isolated products and the comparison of the retention times. The elution order of the products was: tri-alkyl, 1,3-dialkyl, 2,3-dialkyl, 3-monoalkyl and 2-monoalkyl. In all mass spectra of the ethyl ethers, the base peak was m/z 61, while in the case of t-butyl ethers it was m/z 57.

Benzoato de metila e p-clorofenil acetato de metila reagem com benzilamina e pirrolidina levando às correspondentes amidas. Estas reações são mais rápidas na presença de 20 mol% de DBU, fornecendo os produtos com rendimentos levemente superiores. Quando um diéster derivado do ácido L-aspártico foi usado como substrato, a reação com benzilamina e pirrolidina foi quimiosseletiva para o éster metílico, levando às correspondentes amidas em bons rendimentos. Reação do monoéster metílico do ácido aspártico com estas aminas conduziu a amidas com um grupo ácido livre em C1. Anilina, menos básica e menos nucleofílica, não formou os produtos esperados tanto na ausência quanto na presença de DBU. Através do monitoramento da reação por ESI-MS, foi possível interceptar os intermediários-chave catiônicos formados nas reações entre o benzoato de metila e o p-clorofenil acetato de metila com a benzilamina, os quais foram caracterizados por ESI-MS/MS.

Methyl benzoate and methyl p-chlorophenyl acetate react with neat benzylamine and pyrrolidine to form the corresponding amides. These reactions are faster in the presence of 20 mol% of DBU providing slight better yields. When a diester derived from L-aspartic acid was used as substrate, the reaction with benzylamine and pyrrolidine in the presence of DBU was chemoselective and led to the corresponding amides in good yields. Reaction of aspartic acid monomethyl ester with these amines led to amides having a free carboxy group (at C1). Less nucleophilic and less basic aniline failed to form the expected products in both absence and presence of DBU. By monitoring the course of reaction by ESI-MS, key charged intermediates formed by the reactions of methyl benzoate and methyl p-chlorophenyl acetate with benzylamine were intercepted and further characterized by ESI-MS/MS.

The catalytic behavior of Cs-exchanged and Cs-impregnated zeolites (X and Y) was studied using the Knoevenagel condensation between glyceraldehyde acetonide and ethyl acetoacetate in order to produce the corresponding α,β-unsaturated carbonyl compound that is an important intermediate for fine chemicals. The influence of reaction temperature, type of zeolite, and basicity of the sites on the catalytic behavior of the samples was evaluated. All zeolites were active for the studied reaction. The formation of the main condensation product was favored at lower reaction temperatures. Products of further condensations were also observed especially for samples that were only dried before catalytic test.

O a-aminoácido (S)-5 foi sintetizado usando na etapa chave uma reação de substituição nucleofílica quimiosseletiva entre um diéster derivado do ácido L-aspártico e a 2-lítio piridina. O rendimento global (13%, 5 etapas) foi semelhante ao previamente descrito por nosso grupo (12%, 10 etapas) para obtenção do isômero R (o primeiro agonista pleno exógeno de receptores do sub-tipo NMDA) a partir do D-manitol e ao da síntese racêmica relatada por Lovey e Copper (17%, 5 etapas).

The a-amino acid (S)-5 was synthesized using in the key step a chemoselective nucleophilic substitution between a diester derived from L-aspartic acid and 2-lithium pyridine. The overall yield (13%, 5 steps) was similar to those previously described by our group for the R isomer (the first exogen full agonist of the NMDA receptors) from D-mannitol (12%, 10 steps) and by Lovey and Copper for the racemic synthesis (17%, 5 steps).

A tandem syn-selective conjugate addition - Nef reaction was observed when phenylnitromethane and oxygenated derivatives were allowed to react with an enoate derived from D-mannitol at rt in the presence of TBAF or DBU. While nitro-adducts predominate after 4h of reaction, the corresponding ketones were the main products after 12-24h of reaction. The Nef reaction occurred without racemization of the stereogenic center generated in the conjugate addition step.