Yield:37978-59-9 95%

Reaction Conditions:

with trifluoroacetic acid in water at 20; for 0.333333 h;

Steps:

15 Method 15; E-3-METHOXYCARBONYL-4- (5-METHYLFUR-2-YL)-BUT-3-ENOIC ACID

A solution of E-3-METHOXYCARBONYL-4- (5-METHYLFUR-2-YL)-BUT-3-ENOIC acid t-butyl ester (Method 16; 1.39g, 4.96 mmol) in trifluoroacetic acid/water (20ML of 90: 10 v/v) was stirred at ambient temperature for 20 mins; the reaction mixture was then diluted with toluene (30 ml) and evaporated in vacuo to yield a brown oil. After further azeotroping with toluene (30ML), this set solid; trituration with isohexane and collection of the residue yielded the title compound as a brown solid (1. 05G, 95%). NMR 2.33 (s, 3H), 3.65 (s, 2H), 3.72 (s, 3H), 6.29 (d, 1H), 6.85 (d, 1H), 7.41 (s, 1H), 12.34 (bs, 1H).

References:

WO2004/46139,2004,A1 Location in patent:Page 27