95239-58-0Relevant academic research and scientific papers
Henry condensations with 4,6-O-benzylidenylated and non-protected D-glucose and L-fucose via DBU-catalysis
Phiasivongsa, Pasit,Samoshin, Vyacheslav V.,Gross, Paul H.
, p. 5495 - 5498 (2003)
Mechanistic intermediates, and thermodynamically favored side products, in the Henry condensations of partially protected and non-protected pyranoses with a free anomeric hemiacetal function with nitromethane in various solvents for the kinetically controlled syntheses of C-glycopyranosides in the presence of DBU/molecular sieve catalyst system were identified.
C-glycoside synthesis II: Henkt condensations of 4,6-O-alkylidene pyranoses with a 1,3-proton transfer catalyst- a roote to blocked aminomethyl-c-glycosides
Drew, Kenneth N.,Gross, Paul H.
, p. 6113 - 6126 (2007/10/02)
In the presence of a novel 1,3-proton transfer catalyst (2-hydroxypyridine (2-HP)/ 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)/molecular sieves), 4,6-Obenzylidene-D-glucopyranose (1),4,6-O-isopropylidene-D-mannose (12), and 4,6-O-isopropyridene-D-glucose (16) undergo Henry condensations with nitromethane in THF to give acetal protected nitromethyl C-glycopyranosides (2, 13, and 17, respectively), which were characterized as their O-acetyl derivatives (5, 15, and 18, respectively). The Henry product from 4,6-O-benzyridene-D glucopyranose could be reduced, with retention of the 4,6-O-benzylidene protecting group, by a specially prepared form of elemental iron in aqueous tetrahydrofuran under CO2 to aminomethyl-C-glycopyranoside (16), characterized as N-acetyl, peracetyl, and N-Cbz derivatives (7, 8, 9, 10), and converted with diazonium salt to a triazene derivative (II). Nitroalkenes are only mechanistic intermediates in our condensations with nitromethane, but they undergo Michael additions with a second mole of nitromethane to give novel 5,7-O-alkylidene-1,2-deoxy-1 nitro-2-nitromethyl-D-heptitols (3 and 14) as side-products.
