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With manganese(IV) oxide In dichloromethane at 20℃;
To a solution of compound B-131 (4.0 g, 24 mmol) in dichloromethane (40 mL) was added manganese dioxide (21 g, 24 mmol) at room temperature. The mixture was stirred at room temperature overnight. On completion, the mixture was filtered, and the filtrate was concentrated in vacuo to give compound B-132 (3.4 g, 85percent yield) as a yellow solid. LCMS: (ES+) m/z (M+H)+ = 164.1, tR=0.537.
EXAMPLE N 2-Chloromethyl-thieno[2,3-b]pyridine Thieno[2,3-b]pyridine-2-carboxaldehyde (1.63 g) prepared according to J. Het. Chem. 355 (1974) was dissolved in ethanol (20 ml) and to the solution was added sodium borohydride (0.19 g). After 30 minutes the solution was evaporated to dryness and the residue extracted with methylene chloride (50 ml). The organic extract was washed with water (2*25 ml), the extract dried and then evaporated to obtain 2-hydroxymethylthieno[2,3-b]pyridine (1.40 g) as an amber oil. 'H-NMR (CDCl3,60 MHz): 4.9 (s, 1H), 6.3 (s, 1H), 6.9 s, 1H), 7.1 (m, 1H), 7.8 (m, 1H), 8.4 (m, 1H).
This product was dissolved in a solution of pyridine (2 ml) in methylene chloride (20 ml) and to the resulting solution was added methane sulfonyl chloride (1.14 g). Upon stirring overnight at room temperature, the solution was poured onto ice water (25 ml). The methylene chloride layer was separated, washed with water (2*10 ml) and then dried and evaporated. The residue was purified by chromatography on silica gel with a mixture of methylene chloride-ethyl acetate (9:1) as eluant to obtain the title compound (0.76 g; m.p. 47-49 C.).
With lithium aluminium tetrahydride; In tetrahydrofuran; for 4.0h;
To a mixture of compound B-130 (10 g, 52 mmol) in anhydrous tetrahydrofuran (100 mL) was added lithium aluminum hydride (4.0 g, 0.10 mol) at 0 C. The mixture was stirred at 0 C for 4 h. On completion, the solution was quenched with water (5 mL) at 0 C and filtered. The filtrate was concentrated in vacuo to give compound B-131 (7.0 g, 82% yield) as a yellow solid. LCMS: (ES+) m/z (M+H)+ = 166.2, tR=0.249.
With manganese(IV) oxide; In dichloromethane; at 20.0℃;
To a solution of compound B-131 (4.0 g, 24 mmol) in dichloromethane (40 mL) was added manganese dioxide (21 g, 24 mmol) at room temperature. The mixture was stirred at room temperature overnight. On completion, the mixture was filtered, and the filtrate was concentrated in vacuo to give compound B-132 (3.4 g, 85% yield) as a yellow solid. LCMS: (ES+) m/z (M+H)+ = 164.1, tR=0.537.