Water → α-Methyl-4-thiazoleacetic acid

A solution of 5.0 g (27 mmol) of ethyl 2-(1,3-thiazol-4-yl)propanoate from step A above in 25 mL of methanol was added dropwise to a mixture of 6.6 mL (33 mmol) of a 5 N aqueous NaOH solution, water (16 ml) and methanol (30 ml). After addition was complete the mixture was stirred for 2 h. The methanol was removed by evaporation and the pH of the remaining aqueous was adjusted to ˜2.5 with a concentrated hydrogen chloride solution. The mixture was saturated with solid sodium chloride and extracted with EtOAc (3×100 mL). The combined organic layers were washed with brine, dried over sodium sulfate and treated with activated charcoal overnight. The mixture was filtered and evaporated to afford the title compound as an off-white solid 4.0 g (95%). 1H NMR (500 MHz, CDCl3) δ: 1.63 (d, J=7.3, 3H), 4.11 (q, J=7.3), 7.25 (d, J=1.8, 1H), 8.88 (d, J=1.8, 1H), 10.25 (br s, 1H).

1. additionAfter addition
2. customThe methanol was removed by evaporation
3. extractionextracted with EtOAc (3×100 mL)
4. washThe combined organic layers were washed with brine
5. dry with materialdried over sodium sulfate
6. additiontreated with activated charcoal overnight
7. filtrationThe mixture was filtered
8. customevaporated

ORD record

ord-446c9cdb1f664119878f40ba2a8e0562

Source dataset

uspto-grants-2013_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08399480B2