Synthesis and mechanism of organic and organometallic compounds.

Catalysis and Catalysts

Prof. Norma Nudelman

Synthesis and mechanism of organic compounds

Stability studies of benzodiazepines

We have studied the kinetics of the reaction of 2-amino-5-chlorobenzophenones with several [HCl] in methanol:water at 60 and 80°C. Chlorination and cyclization reactions that give rise to products were not expected to occur under the conditions of the reaction and this study contributes to the knowledge of these unexpected reactions and analyze the efect of the sustituyents. The study of the reactions in the presence of N2 and m-dinitrobenzene contributes to elucidate the presence of a radicalary mechanism in the step of chlorination.

We are studing the oxidation of alprazolam. The isolation and structural determination of the products as well as the effects of solvent, pH, temperature, or a combination of these parameters on the rates of degradation of the drug and the rates of formation of the different reaction products, would afford useful clues regarding drug formulation, storage and analytical procedures.

Synthesis and mechanism of organometallic compounds

Synthesis and mechanism of alkyltin compounds

In recent years several mechanisms have been proposed for the formation of tretraalkyltin compounds by the reaction of organic-halides with triorganostannyl-alkali-metal compounds. The three basic mechanistic pathways which have been described are: a) a classic SN2 substitution of the alkyl halide with a trialkylstannyl anion as the nucleophile, b) substitution by an electron-transfer (ET) process, and c) substitution by halogen-metal exchange (HME).

According to this and taking into account the expierence of these group in reactions of alkyl-lithium under CO atmosphere, we began to study the reaction of trialkylstannyl-lithium with different organic-halides in the presence of CO

Synthesis and mechanisms of organolithium compounds

Carbonylation of organolithium compounds

We are studying the structural characteristics of organolithium compounds; usually, these reagents exist as aggregates in solid state as well as in solution, as dimers, trimers, tetramers and higher oligomers and can form mixed aggregates. The reactions of organolithium compounds with carbon monoxide are very important in organic synthesis, since they provide a useful tool for the preparation of a wide diversity of molecules containing one or more carbonyl functionalities.

The research is focused in mechanistic and synthetic studies about the carbonylation of aryllithium compounds, alkyllithium compounds and lithium amides. These works aim to search alternative methods for the preparation of compounds with known clinic activity and highly functionalized compounds .

Agregation states of organolithium compounds and its possible influence on reactivity

We have studied the influence of the aggregation state of organolithium compounds in their reactivity. The addition of aryllithium to carbonylic compounds have been studied and the effect of their aggregation evaluated, with the variation of the experimental conditions, such as solvent, temperature and concentration.

Kinetic studies have been carried out in order to determine the mechanism of this addition, which appear to be an electron transfer proccess. By EPR measurements the existence of radicals in the first step of the reaction has been determined. UV spectroscopy can be used to carry out these kinetics experiments.

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