Guaiacol (I) was alkylated by means of boiling dibromoethane (II) to produce the bromoethyl ether (III). From this, the intermediate amine (VI) was prepared by Gabriel synthesis, via condensation with potassium phthalimide (IV) in hot DMF, followed by hydrazinolysis of the resultant N-substituted phthalimide (V).
The condensation of vanillin (VII) with epichlorohydrin (VIII) in ethanolic NaOH produced the glycidyl ether (IX). Epoxide ring opening in (IX) by means of amine (VI) in EtOH furnished amino alcohol (X). The title dihydropyridine derivative was then obtained by reaction between aldehyde (X), methyl acetoacetate (XI), and ammonia under Hantzsch condensation conditions.
The condensation of vanillin (I) with epichlorohydrin (II) in ethanolic NaOH produced the glycidyl ether (III). Epoxide ring opening in (III) by means of tert-butylamine (IV) in EtOH furnished amino alcohol (V). The title dihydropyridine derivative was then obtained by reaction between aldehyde (V), methyl acetoacetate (VI), ammonia under Hantzsch condensation conditions, and was isolated after conversion to the hydrochloride salt.