Alkaloids from the roots of Aconitum pseudo-laeve var. erectum.

One new quinazoline (1) and two new norditerpenoid (2 and 3) alkaloids along with 10 known compounds were isolated from the roots of Aconitum pseudo-laeve var. erectum. The new alkaloids were assigned as 2-(2-methyl-4-oxo-4H-quinazoline-3-yl)benzoic acid methyl ester (1), 18-O-2-(2-methyl-4-oxo-4H-quinazoline-3-yl)benzoyllycoctonine (2), and 14-O-acetyl-8-O-methyl-18-O-2-(2-methyl-4-oxo-4H-quinazoline-3-yl)benzoylcammaconine (3). The structures of the new alkaloids were established by spectroscopic methods. This is the first report of the 2-(2-methyl-4-oxo-4H-quinazoline-3-yl)benzoyl ester group being found as an acyl substituent in norditerpenoid alkaloids (compounds 2 and 3).