Benzyltetrahydroisoquinoline Alkaloids with Three Oxygenated Substituents

By methylation of natural coclaurine with formaldehyde and formic acid Tomita and Kusuda obtain optically inactive A-methylcoclaurine (mp 122°-123° or 161°-162°) 21, 27). As optically active A-methyl-coclaurine had been obtained by reductive fission of bisbenzylisoquino-line alkaloids with sodium in liquid ammonia 28), it is evident that natural coclaurine is a racemic modification in disagreement with the report of Kondo and Kondo (see Volume IV, p. 65). Racemic coclaurine has been recently resolved in its enantiomers through the di-O-benzoyl-tartrate of the 0,0-dibenzyl derivative and hj drogenolysis of the benzyl groups 29) (-h )-coclaurine ([a]j) -f 13° in CH3OH) (— )-coclaurine ([ ]j) —14°). The absolute configuration was established by methylation with formaldehyde and formic acid (-h)-coclaurine gives d-( —)-A-methylcoclaurine. 

Two new syntheses of coclaurine following the usual route (see Volume IV, p. 67) have been reported 30, 31). Kametani et al. 32) synthesized (— )-coclaurine by a somewhat new procedure. They condensed 4-benzyl- 

Haynes et al. (29) showed by feeding experiments on Croton linearis Jacq. with tritium-labeled compounds that d-( — )-coclaurine is 

Coclaurine is devoid of bactericidal action. It lowers blood pressure in dogs by direct action on the myocardium 24). 

L-( + )-i T-Methylcoclaurine, C19H23NO3 (XIII), has been isolated from Cocculus laurifolius DC. (Menispermaceae) and named coclanoline (33) (vide infra). D-( — )-iV -Methylcoclaurine was isolated from Phylica rogersii Pillans (Rhamnaceae) (34). Both enantiomers have been obtained in many cases by reductive cleavage with sodium in liquid ammonia of bisbenzylisoquinoline alkaloids (11, 12). 

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II. Benzyltetrahydroisoquinoline Alkaloids with Three Oxygenated Substituents 404... 

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