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24472-57-9

5-Pentylpyridine-2-carboxylic acid synthesis

3synthesis methods
2-Pyridinecarboxylic acid, 5-pentyl-, ethyl ester

108734-05-0
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5-Pentylpyridine-2-carboxylic acid

24472-57-9
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Yield:24472-57-9 85%

Reaction Conditions:

Stage #1: 5-pentyl-pyridine-2-carboxylic acid ethyl esterwith sodium hydroxide;water in methanol at 20; for 2.5 - 3 h;
Stage #2: with sodium hydroxide in water;ethyl acetate;
Stage #3: with hydrogenchloride in water; pH=5;Acidic aqueous solution;

Steps:



The ethylester 66 (7.37 g, 33.3 mmol) was dissolved in MeOH (150 ml) followed by the addition of aq. NaOH (2 M, 53 ml, 106 mmol). The reaction mixture was stirred at rt for 2.5 h and concentrated under reduced pressure. To the aqueous residue was added EtOAc (80 ml) followed by the extraction with NaOH (10%, 2×80 ml). The combined aqueous layers were acidified to pH=5 by the addition of hydrochloride acid (1 M aq). The product was extracted with EtOAc (2×250 ml). The combined organic layers were dried with magnesium sulfate, filtered and concentrated under reduced pressure to give 5.53 g (85%) of 5-pentyl-pyridine-2-carboxylic acid (67). LC-MS: tR=0.66 min; [M+H]+=194.16.

References:

US2008/76762,2008,A1 Location in patent:Page/Page column 47-48; 61