The natural product acivicin inhibits the glutaminase activity of cytidine triphosphate (CTP) synthetase and is a potent lead compound for drug discovery in the area of neglected tropical diseases, specifically trypanosomaisis. A 2.1-Å-resolution crystal structure of the acivicin adduct with the glutaminase domain from Trypanosoma brucei CTP synthetase has been deposited in the RCSB Protein Dat...

Novel 5α-androstanes containing an isoxazoline moiety condensed to ring A or D were efficiently synthetized by 1,3-dipolar cycloadditions of aryl nitrile oxides to steroidal α,β-unsaturated ketones. During the ring closures, regioisomers in which the O terminus of the nitrile oxide dipoles is attached to the β-carbon of the dipolarophile were formed in a stereoselective manner to furnish exclus...

The title compound, C27H18Cl2N2O2, represents a racemic mixture of the corresponding R,R and S,S diastereomers. The isoxazoline ring adopts an envelope conformation with the spiro C atom deviating by 0.093 (2) Å from the rest of the ring. The six-membered keto-substituted carbocycle has a sofa conformation with the methyl-ene C atom adjacent to the spiro center deviating by 0.289 (2) Å from the...