Pentacyclic triterpenoids oleanolic acid, ursolic acid, betulinic acid, and platanic acid were acetylated and converted into several amides 9–31; the cytotoxicity of which has been determined in sulforhodamine B assays employing seral human tumor cell lines and nonmalignant fibroblasts. Thereby, a betulinic acid/trans-1,4-cyclohexyldiamine amide showed excellent cytotoxicity (for example, EC₅₀ = 0.6 μM for HT29 colon adenocarcinoma cells).

Analysis of several batches of the a1–adrenergic blocking agent terazosin being used as a medication for treating benign prostatic hyperplasia and hypertension revealed the presence of a hitherto not reported impurity. The latter was isolated, and its structure was elucidated from NMR and Mass Spectrometry (MS) data and unambiguously confirmed by independent synthesis. This contamination, represented in 1-[4-(amino-6,7-dimethoxyquinazolin-2-yl)-piperazin-1-yl]-pentane-1,2-dione 2 is likely to occur as the product of a side-reaction in the catalytic hydrogenation step during the synthesis of the drug. Biological screening showed this compound as not cytotoxic for several human tumor cell lines and non-malignant fibroblasts.