New C2 symmetrical and semisymmetrical substituted imidazolium ribonucleoside. Imidazolic nucleosides analogues
摘要:
New C-2 symmetrical imidazolium ribonucleosides have been synthesized. The silyl Hilbert Johnson-Vorbrugen method was used. Subsequent coupling of trimethylsilylimidazole with the peracylated D-ribofuranose 1, followed by removal of the protecting groups, afforded 1,3-bis(beta-D-ribofuranosyl)imidazolium 7 and 1-(beta-D-ribofuranosyl)imidazole 8. In a similar synthetic sequence, 4(5)-substituted bis-ribofuranosylimidazolium 14 was also prepared, For the selective preparation of the monoglycosylated imidazole 15, the classical method starting from 2,3,5-tri-O-benzoyl-D-ribofuranosyl bromide in acetonitrile and using Hg(CN)2 was employed. These new base modified nucleosides were devoid of activity against HIV and cytotoxicity. Copyright (C) 1996 Elsevier Science Ltd.
A versatile, enantioselective, stereocontrolled synthesis of (1S,2R)-imidazoleglycerol
摘要:
An efficient (21% overall yield), enantio- and diastereoselective, 11-step synthesis of (1S,2R)-imidazoleglycerol has been developed. The key steps are the stereoselective hydroxylation of an acyloxazolidinone enolate, the alkylation of a thioester with (MOMOCH(2))(2)CuLi and the stereodivergent reduction of the resulting ketone. The scope of the reaction of the enolate derived from 10 with heteroatom electrophiles has been studied. Copyright (C) 1996 Elsevier Science Ltd
Imidazolium-, pyrazolium-, and bis-benzimidazolium-containing ionic liquids were synthesized from easily available, unprotected carbohydrates such as d-ribose, d-xylose, d-glucose, d-galactose, d-fructose and l-sorbose.