Isolation of a unique dipyridodiazepinone metabolite nevirapine during large scale extraction of Cliv-92 from the seeds of Cleome viscosa

Natural nevirapine (1), a dipyridodiazepinone metabolite has been isolated as a minor constituent with a yield of 0.00397% from the ethyl acetate extract during large scale extraction of Cliv-92 at a level of 100 kg/batch from the seeds of Cleome viscosa. Column chromatographic purification of the ethyl acetate extract afforded the molecule which was characterized as nevirapine through spectral analysis and confirmed by single crystal X-ray crystallography. The molecule also has been re-isolated from the same batch of seeds to confirm its presence in the seeds of C. viscosa. The molecule nevirapine has been fully characterized by co-TLC, prep-TLC-MS/MS and chiral HPLC analysis. Isotope Ratio Mass Spectrometric (IRMS) analysis of natural nevirapine and the synthetic drug revealed it to be different. It is an interesting discovery to find out that the natural nevirapine exists as an endogenous metabolite of the plant. This paper also reports the isolation of salicylic acid from the same batch of seeds which afforded nevirapine which may have been due to some plant–pathogenic interaction.

► Isolation of a dipyridodiazepinone alkaloid nevirapine. ► Isolation of salicylic acid. ► Chemical fingerprinting of the extracts and re-isolation of the molecule. ► Isotope Ratio Mass Spectrometry (IRMS) and Chiral-HPLC analysis.