112290-60-5Relevant academic research and scientific papers
PHOTOHALOGENATION OF GLYCOPYRANOSYL HALIDES: AN EXPEDIENT ROUTE TO C-1 GEM DIHALOGENATED SUGARS
Praly, Jean-Pierre,Brard, Laurent,Descotes Gerard,Toupet, Loic
, p. 4141 - 4152 (2007/10/02)
Free-radical halogenation of peracetylated α and β-glycopyranosyl halides of 4C1-D chair conformation takes place at C-1 or C-5 with an α-stereoselectivity.However the less reactive α-chloride and bromide moieties at first undergo a dehydrohalogenation reaction. β-Chlorides when treated with N-bromosuccinimde give new C-1 gem chlorobromo sugars in 65-70 percent yield while new C-5 halogenated compounds are obtained predominantly with β -fluorides or when chlorination is carried out with sulfuryl chloride SO2Cl2.The peracetylated C-1 gem chlorobromo derivative of gluco configuration can be cleanly dehydrobrominated to yield a C-1 chlorinated glucal.It also reacts chemio and stereoselctively in the presence of silver flouride to give the corresponding new C-1 gem chlorofluoro or difluoro derivatives, either in 70 percent yield, depending on the stoechiometry.All these new compounds exhibit a good to excellent stability. 19F-n.m.r. of three peracetylated 1-halogeno- β -D-glucopyranosyl fluorides shows that the JF,C coupling constants increase with the increasing electronegativity of the geminal axial halogen while JF,H decreases.
SYNTHESES OF "ANOMERIC" GEM DIHALOGENATED GLUCOPYRANOSYL DERIVATIVES
Praly, J. P.,Descotes, G.
, p. 1405 - 1408 (2007/10/02)
free-radical bromination of peracetylated β-D-glucopyranosyl chloride constitutes an efficient route to new C-1 gem dihalogenated sugars.
