Anomere Methyl‐2‐desoxy‐4‐thio‐D‐erythro‐pentofuranoside

An alternative synthesis of anomeric methyl 2-deoxy-4-thio-D-erythro-pentofuranosides

“…Methyl 2,3-Anhydro-d-L-lyxopyranoside (2). A chloroform (50 ml) solution of methyl 2-0-benzoyl-3-0-(p-toluenesulfonyl)-d-Larabinopyranoside (1, 21 g, 49.8 mmol) was diluted with benzene (200 ml) and the solution was then cooled to 0 °C.…”

“…Methyl benzoate was removed at 40 °C (10-2 mmHg). Methyl 2,3-anhydro-d-L-lyxopyranoside (2) crystallized readily from ethyl acetate-petroleum ether as long needles (7.15 g, 98%): mp 71-72 °C (lit. 65-66,4 70-70.5 °C3); NMR (acetone-de) 3.37 (s, 3 H, OCH3), 4.85 (d, 1 H, J1|2 = 3 Hz, H-l).…”

“…The readily available starting material, methyl 2-O-benzoyl-3-O-p-toluenesulfonyl-d-L-arabinopyranoside (1), was prepared from methyl 2-0-benzoyl-/3-L-arabinopyranoside by a slight modification of the procedure of Reist et al 3 It has been reported that compound 1 when treated with 2 mol of sodium methoxide in methanol at room temperature for 18 h gives an 80% yield of semicrystalline methyl 2,3-anhydrod-L-lyxopyranoside3 (2). In addition, Buchanan and Fletcher4 showed that treatment of the 4-0-acetyl derivative of 1 with 3 mol of sodium methoxide in methanol at room temperature for 6 h gave a 1:5.6 mixture of methyl 3,4-anhydro-/J-L-arabinopyranoside and 2 in 61% yield; formation of the second epoxide derivative is thought to be due to migration of the epoxide.…”