2-bromo-4-methylpentanoyl chloride

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: 2-Bromo-4-methylpentanoyl chloride (IV, Example 2) is added dropwise to methyl alcohol (200 ml.) at 0°. After two hours the methanol is removed under reduce pressure and the residual oil is partitioned between chloroform and water. The chloroform is separated from the water and removed under reduced pressure to give a residual oil which is distilled under reduced pressure to give the title compound, b.p. 78°-90°/30 mm. After two hours the methanol is removed the residual oil is partitioned between chloroform and water The chloroform is separated from the water removed under reduced pressure to give a residual oil which is distilled under reduced pressure

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: A solution of (±)-2-bromo-4-methyl-pentanoyl chloride, 21 g (0.099 mol), in 25 ml of acetone is added dropwise with stirring to a solution of 10 g (0.099 mol) of L-prolinol and 16.2 g (0.197 mol) of sodium acetate in a mixture of 150 ml of acetone and 75 ml of water at 0°-5° C. The mixture is stirred and allowed to reach room temperature over two hours, the solvent is evaporated in vacuo and the residue is suspended in 300 ml of chloroform and washed with water, 2×300 ml. The chloroform layer is separated, dried over sodium sulfate, evaporated in vacuo, and the residue is purified by chromatography using silica gel and eluting with dichloromethane-methanol (95:5) to give (2S)-1-(2-bromo-4-methyl-1-oxopentyl)2-pyrrolidinemethanol (2 position on side chain is R,S mixture), 21 g; mp 79°-82°; [α]D25 -54.0° (c 0.6, methanol). the solvent is evaporated in vacuo washed with water, 2×300 ml The chloroform layer is separated dried over sodium sulfate evaporated in vacuo the residue is purified by chromatography eluting with dichloromethane-methanol (95:5)

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

Procedure: 2-Bromo-4-methylpentanoyl chloride (IV, Example 2) is added dropwise to methyl alcohol (200 ml.) at 0°. After two hours the methanol is removed under reduce pressure and the residual oil is partitioned between chloroform and water. The chloroform is separated from the water and removed under reduced pressure to give a residual oil which is distilled under reduced pressure to give the title compound, b.p. 78°-90°/30 mm. After two hours the methanol is removed the residual oil is partitioned between chloroform and water The chloroform is separated from the water removed under reduced pressure to give a residual oil which is distilled under reduced pressure

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

Procedure: 2-Bromo-4-methylpentanoyl chloride (IV, Example 2) is added dropwise to methyl alcohol (200 ml.) at 0°. After two hours the methanol is removed under reduce pressure and the residual oil is partitioned between chloroform and water. The chloroform is separated from the water and removed under reduced pressure to give a residual oil which is distilled under reduced pressure to give the title compound, b.p. 78°-90°/30 mm. After two hours the methanol is removed the residual oil is partitioned between chloroform and water The chloroform is separated from the water removed under reduced pressure to give a residual oil which is distilled under reduced pressure

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

Procedure: A solution of sodium nitrite (31.55 g) in water (70 ml) was added dropwise to a stirred solution of D-leucine (20 g) in 47% aqueous hydrobromic acid (140 ml)/water (211 ml) at 0° C. The reaction mixture was allowed to warm to room temperature and stirred for 20 hours, then diluted with diethyl ether (600 ml). The organic layer was separated and washed with aqueous sodium metabisulphite (200 ml), dried over sodium sulphate, filtered and the solvent removed under reduced pressure to give 2-bromo-4-methyl-pentanoic acid as a yellow oil (27.6 g) [1H NMR (CDCl3): δ0.93 (d, 3H), 0.98 (d, 3H), 1.75-1.85 (m, 1H), 1.91-1.95 (m, 2H), 4.30 (t, 1H)]. Oxalyl chloride (9.56 ml) was added dropwise to a stirred solution of the 2-bromo-4-methylpentanoic acid (10.7 g) and pyridine (0.1 ml) in dichloromethane (60 ml). The reaction mixture was stirred for 20 hours and the solvent was removed under reduced pressure to give 2-bromo-4-methylpentanoyl chloride (12 g) [1H NMR (CDCl3); δ0.95 (d, 3H), 1.01 (d, 3H), 1.80-2.07 (m, 3H), 4.52 (t, 1H)]. A solution of this 2-bromo-4-methylpentanoyl chloride (12 g) in dichloromethane (40 ml) was added dropwise to a stirred solution of 2,6-dimethoxy-4-methylphenol (9.41 g) and triethylamine (15.6 ml) in dichloromethane (20 ml). The reaction mixture was stirred for 20 hours and was then chromatographed on silica gel, eluting with dichloromethane, to give the title compound as a viscous yellow oil (14.7 g). was then chromatographed on silica gel eluting with dichloromethane

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

Procedure: A solution of sodium nitrite (31.55 g) in water (70 ml) was added dropwise to a stirred solution of D-leucine (20 g) in 47% aqueous hydrobromic acid (140 ml)/water (211 ml) at 0° C. The reaction mixture was allowed to warm to room temperature and stirred for 20 hours, then diluted with diethyl ether (600 ml). The organic layer was separated and washed with aqueous sodium metabisulphite (200 ml), dried over sodium sulphate, filtered and the solvent removed under reduced pressure to give 2-bromo-4-methyl-pentanoic acid as a yellow oil (27.6 g) [1H NMR (CDCl3): δ0.93 (d, 3H), 0.98 (d, 3H), 1.75-1.85 (m, 1H), 1.91-1.95 (m, 2H), 4.30 (t, 1H)]. Oxalyl chloride (9.56 ml) was added dropwise to a stirred solution of the 2-bromo-4-methylpentanoic acid (10.7 g) and pyridine (0.1 ml) in dichloromethane (60 ml). The reaction mixture was stirred for 20 hours and the solvent was removed under reduced pressure to give 2-bromo-4-methylpentanoyl chloride (12 g) [1H NMR (CDCl3); δ0.95 (d, 3H), 1.01 (d, 3H), 1.80-2.07 (m, 3H), 4.52 (t, 1H)]. A solution of this 2-bromo-4-methylpentanoyl chloride (12 g) in dichloromethane (40 ml) was added dropwise to a stirred solution of 2,6-dimethoxy-4-methylphenol (9.41 g) and triethylamine (15.6 ml) in dichloromethane (20 ml). The reaction mixture was stirred for 20 hours and was then chromatographed on silica gel, eluting with dichloromethane, to give the title compound as a viscous yellow oil (14.7 g). the solvent was removed under reduced pressure

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

Procedure: 2-Bromo-4-methylpentanoyl chloride (IV, Example 2) is added dropwise to methyl alcohol (200 ml.) at 0°. After two hours the methanol is removed under reduce pressure and the residual oil is partitioned between chloroform and water. The chloroform is separated from the water and removed under reduced pressure to give a residual oil which is distilled under reduced pressure to give the title compound, b.p. 78°-90°/30 mm. After two hours the methanol is removed the residual oil is partitioned between chloroform and water The chloroform is separated from the water removed under reduced pressure to give a residual oil which is distilled under reduced pressure