Tetrahedron

From protopines to berbines: synthesis of 1-methoxystylopine and its N-metho salts from coulteropine

M Valpuesta, A Diaz, G Torres, R Suau

Index: Valpuesta, Maria; Diaz, Amelia; Torres, Gregorio; Suau, Rafael Tetrahedron, 2002 , vol. 58, # 25 p. 5053 - 5059

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Citation Number: 11

Abstract

The transformation of protopines into berbines under improved conditions has been used to synthesize 1-methoxystylopine. Coulteropine, the main alkaloid from Romneya coulteri, was used as the starting protopine to accomplish the stereocontrolled synthesis of both cis and transN-methyl-1-methoxystylopinium salts. The results of ab initio calculations (B3LYP/6- 31G∗∗) which are consistent with experimental data, sustain the influence of the C-1 ...