Solidaline, a Modified Protoberberine Alkaloid

A reinvestigation of the alkaloids of Corydalis solida (L.) Swartz (Fumaria-ceae) has yielded the unusual base solidaline, C23H27NO6, 233, 281, 316, 

It should be stated, however, that the alternate structure 51 for solidaline still cannot be completely excluded from consideration. 

Addition of acid at room temperature caused a reversible pseudobase-immonium equilibrium, noticeable in the UV spectrum. Furthermore, upon 

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