Scaevola racemigera

A number of these esters have been prepared by primary synthesis (see Section 30.1). In addition, several such esters have been isolated from diverse plant species neozeylanicine, methyl 1-methyl-2,7-naphthyridine-4-carboxylate (85), from Strychnos cocculoides502 and Neoneuclea zeylanica 597 methyl 5-methy 1-2,7-naphthyridine 4-carboxylate (86), from S. cocculoides 502 4-meth-oxycarbonyl-7-methyl-2,4a,5,6,7,7a-hexahydro-l //-cyclopentapyridin-6-yl 1-methyl-l,2-dihydro-2,7-naphthyridine-4-carboxylate (87), from Scaevola racemigera 931 and three others skin to the last and from the same source.931... 

Scaevoline (101) and racemigerine (102) were isolated from Scaevola racemigera, along with cantleyine, tetrahydrocantleyine, the new tetrahydropyridine monoterpene strychnovoline, and derivatives of the above alkaloids. Structures of 101 and 102 were established with MS, IR, h NMR, and synthesis of 102 from 95 [284]. 

Apocynaceae) (72), from the stem bark of A. undulifolia (73), from the aerial parts of Scaevola racemigera (Goodeniaceae) (39) and from the seeds of Strychnos longicaudata and S. variabilis (Loganiaceae) (71). Ammonia was used in the work-up of the plant material for alkaloids in each of these cases. 

The third monomeric alkaloid characterized from Scaevola racemigera was scaevoline (22), which showed a molecular ion at mJz 205 and was therefore isomeric with 21 (39). Spectroscopically, the IR spectrum showed the presence of a hydroxyl group (3270 cm-1 Sh 3.80 ppm), and the pyridine a-protons were present (8.77 and 8.46 ppm), as were the carbomethoxy group (3.93 ppm) and a singlet methyl (1.62 ppm). The C-5 methylene group was missing, replaced by two olelinic protons at 7.16 and 6.65 ppm as coupled doublets (/ = 6 Hz). The structure 22 was therefore proposed for scaevoline, which was also isolated in racemic form (39). 

Among the six new monoterpene alkaloids isolated from the aerial parts of Scaevola racemigera (39) was 7-O-nicotinoyl-strychnovoline (66). The molecular ion was observed at m/z 330, with a major fragment ion at m/z... 

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