Synthetic Routes to (+)-Cassiol and (-)-Cassioside

Esta revisão sumariza as seqüências desenvolvidas recentemente para a síntese total das substâncias antiulcerogênicas (+)-cassiol e seu glicosídeo (-)-cassiosídeo. A discussão está centralizada nas estratégias sintéticas e nas metodologias para a construção de centros carbônicos quaternários. This review summarizes the sequences recently developed for the total synthesis of the antiulcerogenic compounds (+)-cassiol and its glucoside (-)-cassioside. The discussion is focused on synthetic strategies and on methodologies for the construction of quaternary carbon stereocenters

Synthetic Routes to (+)-Cassiol and (-)-Cassioside

This review summarizes the sequences recently developed for the total synthesis of the antiulcerogenic compounds (+)-cassiol and its glucoside (-)-cassioside. The discussion is focused on synthetic strategies and on methodologies for the construction of quaternary carbon stereocenters

Synthetic Routes to (+)-Cassiol and (-)-Cassioside

This review summarizes the sequences recently developed for the total synthesis of the antiulcerogenic compounds (+)-cassiol and its glucoside (-)-cassioside. The discussion is focused on synthetic strategies and on methodologies for the construction of quaternary carbon stereocenters

Regioselectivity of the glycosylation of N-dimethylmaleoyl-protected hexosamine acceptors. An experimental and DFT approach

Both anomers of the methyl glycoside of 6-O-benzyl-N-dimethylmaleoyl-D-allosamine (6 and 7) are glycosylated exclusively on O3 when reacting with the trichloroacetimidate of peracetylated α-D-galactopyranose (5). This regioselectivity is expected for 6, the α-anomer, as a strong hydrogen bond of its H(O)3 with the carbonyl group of the dimethylmaleoyl group occurs, as shown by NMR temperature dependence. However, this hydrogen bond was not encountered experimentally for 7, the β-anomer. A DFT study of the energies implied in an analog of the glycosylation reaction charged intermediate has explained neatly this behavior, in terms of strong hydrogen bonds occurring at these charged intermediates. This approach explains both the experimental regioselectivities found for 6 and 7, but furthermore the calculations have shown a marked agreement with the regioselectivities found for other related compounds in the literature.Fil: Colombo, María Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Rúveda, Edmundo A.. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; ArgentinaFil: Stortz, Carlos Arturo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Subsede del Centro de Investigaciones en Hidratos de Carbono | Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono. Subsede del Centro de Investigaciones en Hidratos de Carbono; Argentin

An efficient and environmentally benign chemical synthesis of testolactone

A comparative study of two approaches for the chemical synthesis of the biologically interesting steroid testolactone is described. The first approach is efficient but classical, in the second one, hazardous chemicals were replaced by benign alternatives maintaining the same degree of efficiency

An efficient and environmentally benign chemical synthesis of testolactone

A comparative study of two approaches for the chemical synthesis of the biologically interesting steroid testolactone is described. The first approach is efficient but classical, in the second one, hazardous chemicals were replaced by benign alternatives maintaining the same degree of efficiency