CORYDALDINE has been prepared in a very poor yield by oxidation of corydaline (cf. Dobbie and Lauder, J., 1899, 75, 670), but its constitution had not been confirmed by synthesis. Such a synthesis is now described. The azide (I), obtained from the hydrazide of p-3 : 4-dimethoxyphenylpropionic acid, on being boiled in toluene solution gave a good yield of the isocyanate (11) , which was cyclised to corydaldine (111) by phosphoryl chloride. The yield at this stage was not satisfactory; therefore carbarnides (IV) were prepared by treating the isocyanate (11) with various aromatic amines in the hope that, after a Bischler-Napieralsky condensation to (V), it would be possible to prepare (111) by hydrolysis. This expectation was not realised, for the resultant l-arylimirto-6 : 7-dimethoxy-1 : 2 : 3 : 4ietralzydroisoqzcinolines were quite stable, indicating that they can exist as the l-arylamino-3 : 4-dihydro-tautomerides (VI). Evidence has been obtained that they show virtual taut omerism characteristic of the amidines.
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