(3S,4R)-4-aminooxolan-3-ol

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of the crude trans-4-aminotetrahydrofuran-3-ol (from Step 1), sodium carbonate (7.68 g, 72.5 mmol), tetrahydrofuran (100 mL) and water (100 mL) was cooled to 0° C. and stirred vigorously. Benzyl chloroformate (9.48 mL, 66.4 mmol) was added dropwise. The resulting mixture was stirred at room temperature for 2 h. The organic solvent was removed in vacuo. The aqueous residue was diluted with water (50 mL) and extracted with ethyl acetate (3×70 mL). The combined extracts were dried (MgSO4) and concentrated. Silica gel chromatography, eluting with 30-100% ethyl acetate in hexanes, gave benzyl trans-4-hydroxytetrahydrofuran-3-ylcarbamate as a white solid (8.43 g, 59% yield for 2 steps). 1H NMR (400 MHz, chloroform-d) δ ppm 7.28-7.51 (5 H, m), 5.11 (2 H, br. s.), 4.92 (1 H, br. s.), 4.32 (1 H, br. s.), 3.93-4.17 (3 H, m), 3.50-3.80 (2 H, m), 2.69 (1 H, br. s.); MS (ES+) m/z: 238.1 (M+H); LC retention time: 2.595 min (analytical HPLC Method H). The resulting mixture was stirred at room temperature for 2 h The organic solvent was removed in vacuo The aqueous residue was diluted with water (50 mL) extracted with ethyl acetate (3×70 mL) The combined extracts were dried (MgSO4) concentrated Silica gel chromatography, eluting with 30-100% ethyl acetate in hexanes

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Following the procedure for the preparation of benzyl(3R,4S)-3-[(3,6-diethylpyrazin-2-yl)amino]-4-hydroxypyrrolidine-1-carboxylate but substituting trans-(+/−)-4-aminotetrahydrofuran-3-ol and making non-critical variations provided the title compound as an orange oil. IR (diffuse reflectance) 3356, 3255, 2972, 2938, 1587, 1511, 1464, 1453, 1396, 1337, 1185, 1099, 1064, 965, 888 cm−1; OAMS supporting ions at: ESI+ 238.1; MS (EI) m/z 237 (M+); HRMS (FAB) calcd for C12H19N3O2+H1 238.1555, found 238.1551.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Following the procedure for the preparation of benzyl (3R,4S)-3-[(3,6-diethylpyrazin-2-yl)amino]-4-hydroxypyrrolidine-1-carboxylate but substituting trans-(+/−)-4-aminotetrahydrofuran-3-ol and making non-critical variations provided the title compound as an orange oil. IR (diffuse reflectance) 3356, 3255, 2972, 2938, 1587, 1511, 1464, 1453, 1396, 1337, 1185, 1099, 1064, 965, 888 cm−1; OAMS supporting ions at: ESI+ 238.1; MS (EI) m/z 237 (M+); HRMS (FAB) calcd for C12H19N3O2+H1 238.1555, found 238.1551.

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of the crude trans-4-aminotetrahydrofuran-3-ol (from Step 1), sodium carbonate (7.68 g, 72.5 mmol), tetrahydrofuran (100 mL) and water (100 mL) was cooled to 0° C. and stirred vigorously. Benzyl chloroformate (9.48 mL, 66.4 mmol) was added dropwise. The resulting mixture was stirred at room temperature for 2 h. The organic solvent was removed in vacuo. The aqueous residue was diluted with water (50 mL) and extracted with ethyl acetate (3×70 mL). The combined extracts were dried (MgSO4) and concentrated. Silica gel chromatography, eluting with 30-100% ethyl acetate in hexanes, gave benzyl trans-4-hydroxytetrahydrofuran-3-ylcarbamate as a white solid (8.43 g, 59% yield for 2 steps). 1H NMR (400 MHz, chloroform-d) δ ppm 7.28-7.51 (5 H, m), 5.11 (2 H, br. s.), 4.92 (1 H, br. s.), 4.32 (1 H, br. s.), 3.93-4.17 (3 H, m), 3.50-3.80 (2 H, m), 2.69 (1 H, br. s.); MS (ES+) m/z: 238.1 (M+H); LC retention time: 2.595 min (analytical HPLC Method H). The resulting mixture was stirred at room temperature for 2 h The organic solvent was removed in vacuo The aqueous residue was diluted with water (50 mL) extracted with ethyl acetate (3×70 mL) The combined extracts were dried (MgSO4) concentrated Silica gel chromatography, eluting with 30-100% ethyl acetate in hexanes