| 摘要 |
<p>PURPOSE:To obtain a theobromine derivative useful as a drug by a method with a few side reaction in high purity and high yield, by condensing theobromine or its salt with a specific ketal compound, followed by a condensation reaction. CONSTITUTION:Theobromine shown by the formula I or its salt is condensed with a ketal compound shown by the formula II (n is 2-6; R is 1-3C alkyl; X is halogen, organic sulfonic acid, or acetyl) or formula III (m is 2-3). The reaction is carried out in a solvent, e.g., methanol, etc. at room temperature to 153 deg.C. The prepared reaction product is hydrolyzed under acidic conditions, and a carbonyl- protecting group is removed to give a theobromine derivative shown by the formula IV. The compounds shown by the formulas II and III are obtained by converting corresponding carbonyl group-containing compounds into ketals. The protection of the carbonyl group suppresses characteristically the side reactions during the condensation reaction.</p> |
