| 摘要 |
<p>NEW MATERIAL:A compound of formula I [R1, R2 are H, hydroxyl-protecting group; R3, R4 are H, COOH-protecting group; R5 is H, alkoxy; R6 is H, halogen; or R5 and R6 form a double bond or R2 and R5 may form a single bond; A is formula II (R7 is amino, hydroxyl; R8 is H, azide); where the case in which R8 is H and R5 and R6 form a double bond is excluded] and its salt. EXAMPLE:5'beta-Chloro-4'alpha-hydroxy-4',7'-anhydrogriseolic acid. USE:Remedy for cerebrovascular diseases, brain metabolism activator: it is an action to inhibit phosphodiesterase with low toxicity. PREPARATION:For example, griseolic acid of formula III, as a starting material, is allowed to react with a halogen such as chlorine in an aqueous alkali such as sodium hydroxide at a pH of higher than 12 at 0 deg.C to room temperature to give a compound of formula I (where R1, R3, R4 and R8 are H; R6 is halogen; R7 is amino; R2 and R5 form a single bond).</p> |
