Synthesis of racemic 1,2,3,4-tetrahydroisoquinolines and their resolution
1-Aniline-substituted 3,4-dihydroisoquinolines were obtained in various ways using the Bischler-Napieralski reaction. The effect of the protecting group at the aniline nitrogen atom on the course of the reaction has been studied and it was found that the N-phthalyl group was stable under the cyclization conditions. The dihydroisoquinolines were reduced to the racemic 1,2,3,4-tetrahydroisoquinolines which were resolved by crystallization of the diastereomeric tartrates. Two examples of 1,2,3,4-tetrahydroisoquinolines were obtained in optically pure form (>99%ee).
Keywordsdihydroisoquinolines 1,2,3,4-isoquinolines resolution of isomeric tartrates
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