DMP 543 is similar cognitive enhancer as Linopirdine, although it is thought to be more potent . Synthesis The synthesis starts with a standard scheme for preparing indoxyls. Thus, acylation of diphenylamine with oxalyl chloride leads to the amide. The acid chloride then cyclizes into the ring on heating to afford (3). Reaction of that product with 4-picoline under phase-transfer conditions catalyzed by a quaternary salt affords the carbinol (4) from addition of the transient anion on the methyl group of the picoline to the more electrophilic carbonyl group. The alcohol is then dehydrated by means of acetic anhydride and the resulting olefin hydrogenated to afford the indolone (5). The 3 position is now activated by the adjacent benzene ring on one side and the carbonyl group on the other. Alkylation with α-chloropicoline proceeds with hydroxide as the base to afford Linopirdine (6). Linopirdine synthesis:
DMP 543 is a more potent cognitive enhancer drug than Linopirdine . Synthesis The synthesis starts with a standard scheme for preparing indoxyls. Thus, acylation of diphenylamine with oxalyl chloride leads to the amide. The acid chloride then cyclizes into the ring on heating to afford (3). Reaction of that product with 4-picoline under phase-transfer conditions catalyzed by a quaternary salt affords the carbinol (4) from addition of the transient anion on the methyl group of the picoline to the more electrophilic carbonyl group. The alcohol is then dehydrated by means of acetic anhydride and the resulting olefin hydrogenated to afford the indolone (5). The 3 position is now activated by the adjacent benzene ring on one side and the carbonyl group on the other. Alkylation with α-chloropicoline proceeds with hydroxide as the base to afford Linopirdine (6). Linopirdine synthesis:
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similar cognitive enhancer as Linopirdine, although it is thought to be more potent
a more potent cognitive enhancer drug than Linopirdine