Methyl ester hydrolysis; 2-(2,3,5-Trimethoxy-4-methylbenzoyl)benzoic acid
SyntheticPage 442
DOI:
10.1039/SP442
Submitted Jul 21, 2010, published Jul 22, 2010
Christopher Cooksey (
rsc@chriscooksey.demon.co.uk)
A contribution from
R J H Clark Group, UCL
Chemicals Used
Methyl 2-(2,3,5-trimethoxy-4-methylbenzoyl)benzoate page 441
NaOH
Procedure
Methyl 2-(2,3,5-trimethoxy-4-methyl-benzoyl)-benzoate page 441 (9 g, 26 mmol) was heated under reflux with
NaOH (2 g) dissolved in water (30 cm
3) and
methanol (20 cm
3) for 4 h. After cooling, concentrated
HCl (5 cm
3) was added to give a white crystalline precipitate which was filtered and washed with water to give
2-(2,3,5-trimethoxy-4-methyl-benzoyl)-benzoic acid (8.2 g, 95%), mp. 148.8 ºC.
Author's Comments
Evaporation of the filtrate and refrigeration gave a further 257 mg of product. Some product (464 mg) was recrystallised from methanol (5 cm3) and water (15 cm3) to give white crystals (379 mg), mp. 149.3 ºC.
Raistrick H, Robinson R, Todd AR, J Chem Soc 1937, 80-88, doi: 10.1039/JR9370000080, obtained a product with a very different m.p. 205-208 ºC, from 2,3,6-trimethoxytoluene, phthalic anhydride, AlCl3 in CS2, perhaps the alternative isomer, 2-(2,4,5-trimethoxy-3-methyl-benzoyl)-benzoic acid.
A reaction using 28.2 g of starting material gave a 99% yield.
Using the same procedure,
2-(2,3,5-trimethoxy-benzoyl)-benzoic acid methyl ester was hydrolysed to give 71% of the corresponding acid.
Data
δH (CDCl3) 8.02d (7.9), 7.60t (7.2), 7.52t (7.3), 7.39d (7.6), 7.24s, 3.88s, 3.86s, 3.27s, 2.16s.
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Get structure file (.cdx, .sk2, .mol)
Keywords: carboxylic acids, esters, hydrolysis
