Hydrochloric Acid → 6-Amino-2-butoxy-9-(tetrahydrofuran-3-ylmethyl)-7,9-dihydro-8H-purin-8-one

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Reaction Steps

2-(Butyloxy)-8-(methoxy)-9-(tetrahydro-3-furanylmethyl)-9H-purin-6-amine (Isomer 2, 1.96 gm) was suspended in methanol (20 ml) and 4N HCl in dioxan (10 ml) added with stirring to give a clear solution. After 1.5 h, the solvents were evaporated to low volume and water added with stirring, followed by neutralisation with saturated sodium bicarbonate. The resulting off-white solid was filtered, washed with water and dried, yield 1.73 gm. Initial attempts to recrystallise from methanol or ethanol were unsuccessful. The recovered material was dissolved in glacial acetic acid (10 ml) with heating but precipitated immediately on addition of water (10 ml). Further addition of acetic acid (4 ml) and heating gave a clear solution, from which the product crystallised on allowing to cool. The solid was filtered, washed and dried, yield 1.06 gm (Crop 1). A second crop was obtained from the filtrate on standing, yield 460 mg, which was dissolved in sodium hydroxide and precipitated by the addition of acetic acid and then the recovered solid was heated in methanol (20 ml) with further additions of methanol (15 ml) to the boiling mixture to give a cloudy solution, which was allowed to cool. The resulting solid was filtered off, yield 257 mg. This was combined with the first batch of solid (Crop 1) and added portionwise to boiling methanol (130 ml) to give a slightly cloudy solution. On allowing to cool with stirring, a white solid crystallised out which was filtered off, washed with methanol and dried, to give the title compound yield 1.02 gm.

Provenance & Evidence