Cryptopine, reaction

This series of ten alkaloids may appropriately be called the cryptopine sub-group, since the characteristic nuclear structure of the type was first made clear by Perkin s investigation of cryptopine. They are closely related to the profoberberines, with which they are interconvertible by two characteristic reactions, which have been of great value in their investigation. The two alkaloids formerly known as )S- and y-homochelidonines have now been renamed a- and -ofiocryptopines respectively to distin-... 

The reverse change, viz., the conversion of berberine derivatives by iV-methylation into substances constituted similarly to corresponding derivatives of cryptopine, was achieved by the methylation of dihydroanhydroberberine, to the methochloride, which corresponds to tsocrypto-pine chloride and resembles it closely in character and reactions,... 

In this connection, transannular cyclization reactions between the ketonic carbonyl group and the amino nitrogen atom in medium-sized rings are of great interest. Cryptopine (10) is the most usual example, but not the best investigated case, of this kind. The appropriate inter-... 

Protopine has been isolated from Bocconia frutescens,110 Fumaria judaica,111 F. schleicheri,112 and Papaver bracteatum,146 cryptopine from F. schleicheri,112 and allocryptopine from B. frutescens110 and Zanthoxylum nitidum.141 The protopine ring-system has been prepared from tetrahydrobenzindenoazepines (75) by photo-oxidation to the amides (76) followed by reduction with lithium aluminium hydride and re-oxidation with manganese dioxide.148-150 The tetrahydrobenzindenoazepines have been prepared from A-chloroacetyl-/ -phenylethylamines (73) by cyclization to the lactam (74) followed by reaction with a benzyl bromide and phosphorus oxychloride. -Protopine (77 R R2 — CH2)148 and fagarine II (77 R1 = R2 = Me)149 have been synthesized in this way. 

Protopine, allocryptopine, and cryptopine when irradiated in ethanol or chloroform under a nitrogen atmosphere gave yields of 23% to 76% of coptisine, berberine, and epiberberine. The reaction rate in chloroform was greater than in ethanol (or methanol) and the yields were better 169). 

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