Secobenzylisoquinoline alkaloids

So far only the three following 1,2-secobenzylisoquinoline alkaloids have been isolated from natural sources cryptopleurospermine (159), saxoguattine (160), and pseudoronine (161). Cryptopleurospermine (159) was isolated from 

The main mass fragmentation of secobenzylisoquinoline alkaloids involves bond cleavage between the two benzylic carbonyls. This process is evidenced by the presence of peaks representing fragment ions at m/z 151, found in spectra of all these bases and attributed to the lower portion of the molecules, and ions at m/z 220,236, and 222, found in spectra of 159,160, and 161, respectively, formed from the upper part of the compounds. Similarly, as in the mass spectra of other secoisoquinoline alkaloids incorporating the amino-ethyl substituent, the [H2C=N(CH3)2]+ ion at mjz 58 is the base peak. 

Melting Points and Spectral Characteristics of 1,2-Secobenzylisoquinoline Alkaloids 

A modification (142) of the synthesis of cryptopleurospermine (159) applied the O-benzoyl cyanohydrin of isovanillin benzyl ether (171) for nucleophilic 

Degradative studies were carried out on cryptopleurospermine (159) and saxoguattine (160) to complete the structure proof of these alkaloids (136,137). These bases were first reduced to diols 178 and 179, respectively, and then oxidized to produce two aldehydes, isovanillin and compounds 49 or 156 from 159 or 160, respectively. 

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