5-(2-Oxo-hexahydro-thieno[3,4-d]iMidazol-6-yl)-pentanoic acid Methyl ester synthesis

Yield:875237-68-6 79.5%

Reaction Conditions:

with hydrogenchloride in water at 70; for 7 h;Heating / reflux;

Steps:

d-Biotin methyl ester (2)

d-Biotin methyl ester (2). The d-biotin (1) (10 mmol, 2.44 g) is dissolved in 75 ml of anhydrous methanol. 2.6 g of Amberlite 1R120 ion exchange resin, washed with 2N hydrochloric acid, rinsed with water until neutrality and then dried, beforehand, are added. The solution is brought to reflux (70°) for 7 hours under an inert atmosphere. After returning to ambient temperature, the resin is filtered off and rinsed several times with hot methanol. The filtrate is recovered and the methanol is evaporated off under reduced pressure. 2 g (79.5% yield) of product (2) are obtained in the form of a white powder. [0150] TLC on silica: Rf=0.41 (MeOH:CHCl3, 5:95).

References:

US2004/138446,2004,A1 Location in patent:Page 11; 14