52443-07-9Relevant articles and documents
Improved preparations of some per-O-acetylated aldohexopyranosyl cyanides.
Myers,Lee
, p. 145 - 163 (1986)
3,4,6-Tri-O-acetyl-1,2-O-[1-(exo-, endo-cyano)ethylidene]-alpha-D- galacto- (1a/b), -alpha-D-gluco- (2a/b), and -beta-D-manno-pyranose (3a/b) were stereoselectively isomerized to the corresponding per-O-acetylated 1,2-trans-aldohexopyranosyl cyanides in 75, 16, and 62% yield, respectively, by treatment with boron trifluoride etherate in dry nitromethane. The corresponding per-O-acetylated 1,2-cis-aldohexopyranosyl cyanides were obtained concurrently in respective yields of 1.9, 0.9, and 4.8%. The per-O-acetylaldohexopyranosyl cyanide products were found stable to the reaction conditions and were readily isolated following completion of the rearrangement. It had previously been proved that reaction of 2,3,4,6-tetra-O-acetyl-alpha-D-manno- and -gluco-pyranosyl bromide with mercuric cyanide in nitromethane generates, in the ratio of approximately 1:1, the desired 1,2-trans-glycosyl cyanides and the corresponding 1,2-O-(1-cyanoethylidene) isomers (3a/b and 2a/b, respectively). Treatment of these reaction-mixtures with boron trifluoride etherate in nitromethane effected the rearrangement of 3a/b and 2a/b, thereby facilitating the isolation, and increasing the overall yields, of the per-O-acetylated 1,2-trans-D-manno- and -gluco-pyranosyl cyanides (58 and 30% total yield, respectively) relative to the earlier procedures. The boron trifluoride etherate-mediated reaction of per-O-acetyl-alpha- and -beta-D-galacto-, -alpha- and -beta-D-gluco-, -alpha-D-manno-, and -2-deoxy-2-phthalimido-beta-D-gluco-pyranoses with trimethylsilyl cyanide in nitromethane was also investigated. This reaction provides a "one-flask" synthesis of the corresponding per-O-acetylated 1,2-trans-aldohexopyranosyl cyanides in which 1,2-O-(1-cyanoethylidene) derivatives are isomerized in situ. Finally, improved preparations of the (not readily accessible) per-O-acetylated 1,2-cis-D-manno- and -gluco-pyranosyl cyanides are described. Thus, 2,3,4,6-tetra-O-acetyl-alpha- and -beta-D-mannopyranosyl cyanide (48 and 16% total yield, respectively) and -alpha- and -beta-D-glucopyranosyl cyanide (12 and 39% total yield, respectively) were synthesized by fusion of the corresponding alpha-D-glycosyl bromides with mercuric cyanide.
Substrate based PET imaging agents
-
Page/Page column 44; 45; 46; 49, (2020/11/13)
The present application is directed to radiolabeled imaging agents comprising a radiolabel, and a substrate, pharmaceutical compositions comprising radiolabeled imaging agents, and methods of using the radiolabeled imaging agents. The present application is further directed to methods of preparing the radiolabeled imaging agent. Such imaging agents can used in imaging studies, such as Positron Emitting Tomography (PET) or Single Photon Emission Computed Tomography (SPECT).
Solid-phase synthesis of cyclic C-glycoside/amino acid hybrids by carbamate coupling chemistry and on-support cyclization
Katajisto, Johanna,Loennberg, Harri
, p. 3518 - 3525 (2007/10/03)
A solid-supported synthesis of cyclic C-glycoside/amino acid conjugates is described. For this purpose, N-(tert-butoxycarbonyl)-[6-O-(p- nitrophenoxycarbonyl)-2,3,4-tri-O-(p-toluoyl)-β-D-glycopyranosyl] methylamines derived from galactose and glucose were
(-)-Daucic Acid: Revision of Configuration, Synthesis, and Biosynthetic Implications
Lichtenthaler, Frieder W.,Nakamura, Katsumi,Klotz, Juergen
, p. 5838 - 5843 (2007/10/03)
The synthesis of dihydropyrans with the D-xylo (1), D-ribo, L-arabino, and D-lyxo (2) configuration by one-carbon-atom homologation of D-mannose or D-galactose, terminal oxidation, and directed β elimination revealed (-)-daucic acid isolated from carrots