Sodium Hydroxide → 5-Bromothiophene 2-Oxoacetic Acid

(5-Bromothiophen-2-yl)-oxo-acetic acid ethyl ester (45.6 g, 173 mmol) was dissolved in a mixture of 100 ml THF, 100 ml methanol, and 300 ml water, then treated with 10 N NaOH (26 ml, 260 mmol) at room temperature for 20 hours. Volatile solvents were removed by rotary evaporation. The residue was dissolved in 2 L water and extracted with diethyl ether (250 ml). The aqueous layer was acidified to pH 1 with 6 N HCl, and extracted three times with diethyl ether (3×300 ml). The combined diethyl ether extracts were dried over Na2SO4 and concentrated under vacuum to yield Preparation 1a (38.7 g, 95%). The product was then recrystallized from diethyl ether. m.p. 119-120° C.; MS (M−H)−: 235.1; 1H NMR (300 MHz, CDCl3) δ9.00 (1H, br s), 8.15 (1H, d, J=4.2 Hz), 7.16 (1H, d, J=4.2 Hz). 13C NMR (75 MHz, CDCl3) δ173.80, 159.58, 140.14, 137.17, 132.58, 130.48. IR (KBr) 3326, 3124, 1756, 1634, 1415, 1363, 1308, 1253 cm−1.

1. customVolatile solvents were removed by rotary evaporation
2. dissolutionThe residue was dissolved in 2 L water
3. extractionextracted with diethyl ether (250 ml)
4. extractionextracted three times with diethyl ether (3×300 ml)
5. dry with materialThe combined diethyl ether extracts were dried over Na2SO4
6. concentrationconcentrated under vacuum
7. customto yield
8. customThe product was then recrystallized from diethyl ether

ORD record

ord-7f0093c1fa4b469b9a9ff9e014eb4eaf

Source dataset

uspto-grants-2003_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06613786B2