14-Deacetylajadine [2], a new C19-diterpenoid alkaloid, has been isolated from Consolida ambigua with centrifugally accelerated radial thin layer chromatography (Chromatotron). Its structure has been deduced from spectroscopic data and by chemical correlation with ajadine [3]. Earlier communications (1-3) from our laboratory reported the isolation of seven new and ten known alkaloids from the seeds of Consolida ambigua (L.) P. W. Ball and Heywood. This plant contains a series of lycoctonine-type alkaloids that manifest potent toxicity against mammalian organisms. In the process of isolation of ajacine [1] for certain chemical transformations (4), chromatography of a fraction rich in ajacine yielded a small amount of an unknown alkaloid. Herein we describe the identification of this substance as 14-deacetylajadine [2]. The structure of the new alkaloid, mp 121.3-122.2° (Et₂O), molecular formula C33H46N2O9, was deduced on the basis of the ¹H- and ¹³C-nmr spectral data. The ¹H-nmr spectrum (see Experimental) exhibited the presence of an N-CH₂-CH₃ group, three methoxyl groups, and resonances typical of a C-18 ester residue such as is found in ajacine [1] (3) and ajadine [3] (1). The ¹³C-nmr spectrum, which showed signals characteristic of the above functional groups, compares well with those of ajadine [1], except for the acetate group. This fact was consistent with its mass spectrum which showed the molecular ion (m/z 614) 42 mass units less than that of ajadine. That the hydroxyl group was at C-14 was evident from the appropriate chemical shift difference of C-14 when compared with those of ajacine (5) and ajadine [1], and by the fact that the ¹³C-nmr spectral shifts of the nucleus of 2 were in good agreement with those of 14-deacetylnudicauline [4], which differs in the nature of the C-18 ester residue (6). Structure 2 was confirmed by acetylation with Ac₂O/pyridine. The product showed ir and ¹H-nmr spectra that were identical with those of ajadine [3]. That 2 is not an artifact resulting from hydrolysis of ajadine during isolation was demonstrated by the stability of ajadine [3] under conditions of chromatography over Al₂O₃.