2-(2-(2-Chloroethoxy)ethoxy)ethanol → 2-{2-[2-(2-Hydroxyethoxy)ethoxy]ethyl}-1H-isoindole-1,3(2H)-dione

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Reaction Steps

The subject of the present invention is also the process for preparing the (-)-2-{[2-(2-Aminoethoxy)ethoxy]methyl}-4-(2,3-dichlorophenyl)-3-ethoxycarbonyl-5-methoxycarbonyl-6-methyl-1,4-dihydropyridine, wherein 2-[2-(2-chloroethoxy)ethoxy]ethanol is condensed with potassium phthalimide, in dimethylformamide in the heated state, to form 2-[2-(2-phtalimidoethoxy)ethoxy]ethanol the compound of the formula XIV: ##STR14## which is converted by means of Jones reagent to 2-[2-(2-phtalimidoethoxy)ethoxy]acetic acid, the compound of the formula XV: ##STR15## which is treated with carbonyldiimidazole and Meldrum's acid in the presence of pyridine in methylene chloride to obtain the compound of formula XVI: ##STR16## which is then reacted with (R)-2-phenyl-2-methoxyethanol, the compound of formula XVII: ##STR17## to obtain the β-keto ester of formula XVIII: ##STR18## which is condensed in the presence of ammonium formate in ethanol with a benzylidene compound of formula XIX: ##STR19## to obtain (4R,4'R/4S,4'R)-4-(2,3-dichlorophenyl)-5-methoxycarbonyl-3-(2-methoxy-2-phenylethoxycarbonyl)-6-methyl-2-{[2-(2-phthalimidoethoxy)ethoxy]methyl}-1,4-dihydropyridine, the compound of formula XX: ##STR20## and then: either: this compound is subjected to the action of aqueous sodium bicarbonate solution, in solution in acetonitrile, to obtain (4R,4'R/4S,4'R)-2-[{2-[2-(2-carboxyphenylcarboxamido)ethoxy]ethoxy}methyl]-4-(2,3-dichlorophenyl)-5-methoxycarbonyl-3-(2-methoxy-2-phenylethoxycarbonyl)-6-methyl-1,4-dihydropyridine, the compound of formula XXI: ##STR21## which is treated, after separation by HPLC, with a mixture of glyme and sodium ethylate to obtain a mixture containing (-)-2-[{2-[2-(2-carboxyphenylcarboxamido)ethoxy]ethoxy}methyl]-4-(2,3-dichlorophenyl)-3-ethoxycarbonyl-5-methoxycarbonyl-6-methyl-1,4-dihydropyridine, the compound of formula XXII: ##STR22## and its homolog substituted at the 5-position with an ethoxycarbonyl radical,

Provenance & Evidence