Hydroxyurea derivatives of irofulven with improved antitumor efficacy.

Irofulven is a semi-synthetic derivative of Illudin S, a toxic sesquiterpene isolated from the mushroom Omphalotus illudens. Irofulven has displayed significant antitumor activity in various clinical trials but displayed a limited therapeutic index. A new derivative of irofulven was prepared by reacting hydroxyurea with irofulven under acidic conditions.

Pseudoguaianolides from the flowers of Parthenium hysterophorus.

Chemical investigation on the flowers of Parthenium hysterophorus has resulted in the isolation of four new pseudoguaianolides, hysterones A-D along with the known compounds, parthenin, coronopilin, 2beta-hydroxycoronopilin and tetraneurin-A. The structures of the new compounds were established by interpretation of their spectral (1D and 2D NMR) data. The X-ray crystallographic analysis of hysterones A and C was also carried out.

Sesquiterpenes from Omphalotus illudens.

Three sesquiterpenes, illudosone hemiacetal (1a), isoomphadione (2) and illudiolone (3) were isolated from the liquid culture extract of Omphalotus illudens. Their structures were elucidated by spectroscopic techniques as well as by X-ray crystallographic analysis.

The first conversion of camptothecin to (S)-mappicine by an efficient chemoenzymatic method.

Camptothecin has been converted for the first time to (S)-mappicine via mappicine ketone, which is the sole product of the microwave irradiation of camptothecin. Baker's yeast reduction of mappicine ketone yielded (S)-mappicine in high optical purity.