methyl 4-bromo-2-methylbutanoate

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

Procedure: 4-Bromo-2-methyl-butyric acid (2.16 g, 1 eq, prepared according to the procedure described in J. Am. Chem. Soc. 1990, 112, 2755) was dissolved in MeOH (10 mL) and a few drops of conc. H2SO4 were added. The reaction was stirred at reflux for 16 hours. After reaction completion, as monitored by LC-MS, MeOH was removed under reduced pressure, the oily residue was diluted with water, the pH adjusted to 9 with 10% NaOH, and the product was extracted with Et2O (2×20 mL) and dried over Na2SO4. The title compound was obtained as a colourless oil (1.29 g, 55% yield) after solvent removal. at reflux for 16 hours After reaction completion was removed under reduced pressure the oily residue was diluted with water the product was extracted with Et2O (2×20 mL) dried over Na2SO4

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

Procedure: Pyrrolidine (5.4 mL, 66 mmol) was dissolved in toluene (40 mL). 4-Bromo-2-methyl-butyric acid methyl ester (4.3 g, 22.0 mmol) was added and the reaction stirred at reflux for 2.5 hours. Removal of the solvent and of the excess amine at reduced pressure gave 2-methyl-4-(pyrrolidin-1-yl)-butyric acid methyl ester as a thick oil. The crude product was diluted with MeOH (3 mL) and 1.0M NaOH aq solution (22 mL) was added and the reaction stirred at reflux for 18 hours. at reflux for 2.5 hours Removal of the solvent

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

Procedure: A solution of 4-bromo-2-methyl-butyryl bromide (6.2 g, 43.0 mmol, 1.0 eq) in CHCl3 (10 mL) was cooled at 0° C. MeOH (10 mL) was slowly added and the resulting mixture stirred at room temperature for 16 hours. The solvent was evaporated and the residue dissolved in CHCl3 and washed with water and brine. The organic layer was collected and dried with Na2SO4. Evaporation of the solvent gave 4-bromo-2-methyl-butyric acid methyl ester as thick oil (4.3 g, yield 51%). The solvent was evaporated the residue dissolved in CHCl3 washed with water and brine The organic layer was collected dried with Na2SO4 Evaporation of the solvent