34905-87-8Relevant articles and documents
Stereoselective synthesis of deoxycarbaheptopyranose derivatives: 5a-carba-6-deoxy-α-dl-galacto-heptopyranose and 5a-carba-6-deoxy-α- dl-gulo-heptopyranose
Horasan Kishali, Nurhan,Doan, Dilem,?ahin, Ertan,Gunel, Aslihan,Kara, Yunus,Balci, Metin
, p. 1193 - 1200 (2011)
Two new deoxycarbaheptopyranoses, 5a-carba-6-deoxy-α-dl-galacto- heptopyranose and 5a-carba-6-deoxy-α-dl-gulo-heptopyranose were prepared starting from cyclohexa-1,4-diene. The addition of dichloroketene to cyclohexa-1,4-diene followed by the subsequent reductive elimination and Baeyer-Villiger oxidation in turn led to the formation of a bicyclic lactone. Reduction of the lactone moiety followed by acetylation gave a diacetate with cis-configuration. The introduction of additional acetate functionality into the molecule was achieved by singlet oxygen ene-reaction. The formed hydroperoxide was reduced and then acetylated. The triacetate was further functionalized either by direct cis-hydroxylation using OsO4 or by epoxidation followed by a ring-opening reaction to give the title heptopyranose derivatives. One of the synthesized molecules, galacto-heptopyranose exhibited enzyme specific inhibition against α-glycosidase. On the other hand, they did not show any inhibition for α-amylase. However, both compounds, gulo-heptopyranose and galacto-heptopyranose increased the activity of α-amylase.
The synthesis of monocyclic and bicyclic molecules and their antioxidant properties
Bekfelavi, Esen Y?ld?z,Ku?, Nermin ?im?ek
, p. 249 - 256 (2019/04/26)
The synthesis and antioxidant activity of novel cyclitol, lactone and epoxide derivatives starting from appropriate 1.4-cyclohexadiene are reported in this study. All structures of these products were characterized by 1H NMR, 13C NMR, MS and IR spectroscopy. The antioxidant capacities of some synthesized compounds were studied by using the methods of the scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals. It is seen that the antioxidant properties of two of the five synthesized molecules were close to α-tocopherol.
Oxidative cyclizations in a nonpolar solvent using molecular oxygen and studies on the stereochemistry of oxypalladation
Trend, Raissa M.,Ramtohul, Yeeman K.,Stoltz, Brian M.
, p. 17778 - 17788 (2007/10/03)
Oxidative cyclizations of a variety of heteroatom nucleophiles onto unactivated olefins are catalyzed by palladium(II) and pyridine in the presence of molecular oxygen as the sole stoichiometric oxidant in a nonpolar solvent (toluene). Reactivity studies of a number of N-ligated palladium complexes show that chelating ligands slow the reaction. Nearly identical conditions are applicable to five different types of nucleophiles: phenols, primary alcohols, carboxylic acids, a vinylogous acid, and amides. Electronrich phenols are excellent substrates, and multiple olefin substitution patterns are tolerated. Primary alcohols undergo oxidative cyclization without significant oxidation to the aldehyde, a fact that illustrates the range of reactivity available from various Pd(II) salts under differing conditions. Alcohols can form both fused and spirocyclic ring systems, depending on the position of the olefin relative to the tethered alcohol; the same is true of the acid derivatives. The racemic conditions served as a platform for the development of an enantioselective reaction. Experiments with stereospecifically deuterated primary alcohol substrates rule out a "Wacker-type" mechanism involving anti oxypalladation and suggest that the reaction proceeds by syn oxypalladation for both mono- and bidentate ligands. In contrast, cyclizations of deuterium-labeled carboxylic acid substrates undergo anti oxypalladation.
