Synthesis and Biological Evaluation of 3,16,20-Polyoxygenated Steroids of Marine Origin and Their Analogs

ABSTRACT The natural polyoxygenated steroids (20S)-20-hydroxycholestane-3,16-dione (1), (16S, 20S)-16,20-dihydroxycholestan-3-one (2), (20S)-20-hydroxycholest-1-ene-3,16-dione (3) and (20S)-20-hydroxycholest-4-ene-3,16-dione (4), isolated from the gorgonian, Leptogorgia sarmentosa and unnatural analogs (5) (6)

A Facile Palladium Catalysed 3-Component Cascade Route to Functionalised Isoquinolinones and Isoquinolines

Palladium catalysed three component cascade process, involving coupling of 2-iodobenzoates, -benzaldehydes, or acetophenones with substituted allenes and ammonium tartrate as an ammonium surrogate, provides a novel and facile route to substituted functionalised isoquinolinones and isoquinolines in good yields

New Strategy for Synthesis of the Disaccharide Moiety of the Highly Potent Anticancer Natural Product OSW-1

<div><p></p><p>The facile synthesis of a partially protected OSW-1 disaccharide moiety, having a 2-O-p-methoxybenzoyl-β-D-xylopyranosyl-(1 → 3)-2-O-acetyl-L-arabinopyranoside structure, was elaborated by glycosylation in a β-stereoselective fashion. The xylopyranose donors were synthesized by a short synthetic approach via convenient selective 1,2-diacetal protection of 3,4-<i>trans</i>-diequatorial hydroxyl group. Regioselective ring opening of 1,2-diacetal-protected substrates efficiently led to the arabinopyranose acceptor with a free 3-hydroxyl group. Glycosylation of the xylopyranose donor with the arabinopyranose acceptor provided the β-disaccharide.</p> </div

Transforming rhinacanthin analogues from potent anticancer agents into potent antimalarial agents.

Twenty-six novel naphthoquinone aliphatic esters were synthesized by esterification of 1,4-naphthoquinone alcohols with various aliphatic acids. The 1,4-naphthoquinone alcohols were prepared from 1-hydroxy-2-naphthoic acid in nine steps with excellent yields. Twenty-four of the novel synthetic naphthoquinone esters showed significant antimalarial activity with IC(50) values in the range of 0.03-16.63 microM. The length of the aliphatic chain and the presence of C-2' substituents on the propyl chain affected the activity. Interestingly, compounds 31 and 37 showed very good antimalarial activity and were not toxic to normal Vero cells, and the PTI values of 31 (>1990.38) and 37 (1825.94) are excellent. Both 31 and 37 showed potent inhibition against P. falciparum 3D7 cyt bc(1) and no inhibition on rat cyt bc(1). They showed IC(50) values in the nanomolar range, providing full inhibition of cyt bc(1) with one molecule inhibitor bound per cyt bc(1) monomer at the Q(o) site

Biosynthetic Origins of Menisporopsin A

Menisporopsin A, produced by <i>Menisporopsis theobromae,</i> shows antimalarial, antimycobacterial, and cytotoxic activities. Here, we report the first ¹³C incorporations at individual carbons of menisporopsin A using sodium [1-¹³C] and [2-¹³C] acetate. This result indicates that each of the subunits of the pentalactone menisporopsin A is assembled by a polyketide synthase