The anomeric configuration of 3-D-glycosyl-6-methyluracils and the synthesis of related compounds

Synthesis of nucleosides. 10. General synthesis of N-glycosides. II. Synthesis of 6-methyluridines

“…After workup,1 chromatography on neutral alumina (300 g, activity III) gave on elution with n-hexane-ethyl acetate (9:1) a mixture of unreacted sugar and Ni,N3-diriboside 5 (400 mg). 5 was purified by preparative tic on silica gel using the same solvent system and obtained as a white foam: mp 110-112°; yield 0.170 g (3.4%); nmr (CDC13) 6.64 [d, 1, J = 2 Hz, H-l' (N3)], 5.77 [s, 1, H-l' (Ni)[, 5.65 (s, 1, H-5), 2.30 The Ni-nucleoside 3 was eluted from alumina with ethyl acetate-methanol (9:1) and crystallized (CH2Cl2-pentane) giving 2.316 g (40.6%) of 3, mp 126-129°, [a]20D -5.0°(c 1, CHC13) (lit.5 125-128°).…”

“…On reaction of 1 with 15 and SnCl4 in acetonitrile we isolated in 42.3% yield the crystalline N3-glucoside6'14 16 but no Ni-glucoside 17 could be detected. However,6 gave with 15 in acetonitrile besides 1.2% N3-glucoside 18 a 22.4%…”