Corydalis alkaloids, minor

Minor Corydalis Alkaloids. The following four alkaloids have been isolated by Manske from various Corydalis species but have not yet been assigned to chemical groups. Cularine has been compared pharmacologically with papaverine and hydrastine, and may prove to be related to one of these alkaloids. 

The plant Corydalis decumbens (Thunb.) Pers. (Papaveraceae) and the crude alkaloid fraction separated from the plant have been used in folk medicine in China to treat hypertension, hemiplegia and pseudomyopia. Several isoquinoline alkaloids such as berberine, bicuculine, bulbocapnine, jatrihizine, palmatine, tetrahydropalmatine and minor new alkaloids decumbenine, decumbenine B and decumbenine C were separated from the alkaloid fraction of the plant by repeated chromatography on silica-gel column. The structure of decumbenine 2-1, decumbenine B 2-2 and decumbenine C 2-3 are determined by spectral analyses and comparison with known isoquinoline alkaloids (Scheme 2). 

Two new minor alkaloids isolated from Corydalis incisa, along with the lactam oxycorynoline (150), are 12/3-hydroxycorynoline (151 R +R = CH2 R = 0H) and 11-epicorynoline (152). These structures were established by spectroscopy and by chemical correlation with derivatives of corynoline. Two routes, for instance, were found from the latter to 12/3-hydroxycorynoline (151) and its 12a-epimer. (-l-)-14-Epicorynoline has the absolute stereochemistry depicted in (153), as shown... 

Bocconoline, a minor alkaloid from Bocconia cordata Willd., (Papaveraceae) has structure (154). Corynolamine (155), isolated from Corydalis incisa Pers. (Fumariaceae) together with corynoline and corynoloxine, is structurally related to bocconoline since it too possesses a C-8 hydroxymethyl function. 

Cryptopine, C21H23O6N, was first isolated from the thebaine fraction of the opium alkaloids (1), and this was its only known source when W. H. Perkin, Jr., began and successfully completed his classical researches on its structure. It has since been found in the following plants, albeit always as a minor constituent—Corydalis sempervirens (L.) Pers. (2), C. scouleri Hook. 

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