Synthesis and characterization of diazonium functionalized nanoparticles for deposition on metal surfaces.

Silica nanoparticles were surface-functionalized with diazonium groups. The reaction steps leading to the formation of the diazonium functionality were followed with IR and XPS, and the structure of the diazonium-functionalized nanoparticle was confirmed with solid state NMR. Nanoparticle size distribution was determined with DLS, SEM, and TEM.

Antiherpes virus activities of new 6-19 carbon-bridged steroids and some synthetic precursors.

Three synthetic 6,19-carbon bridged steroids: 3beta,20beta-diacetyloxy-5alpha-chloro-19a(R)-hydroxy-6,19-methanopregnane, 3beta,20beta-diacetyloxy-5alpha-chloro-6,19-methanopregnane, 6,19-methanopregn-4-ene-3,20-dione and four synthetic precursors: 3beta,20beta-diacetyloxy-19-hydroxypregn-5-ene, 3beta,20beta-diacetyloxy-pregn-5-en-19-al, 3beta,20beta-diacetyloxy-19(E)-(methoxymethylidene)-pregn-5-ene and 20beta-acetyloxy-3beta-hydroxy-19(E)-(methoxymethylidene)-pregn-5-ene were tested against herpes virus replication in cell cultures. Several compounds were cytotoxic for stationary cells. Antiviral studies performed with all compounds against HSV-1 indicated a dose-dependent virus susceptibility with selectivity indexes (SI) values in the range 1.

6,19-carbon-bridged steroids. Synthesis of 6,19-methanoprogesterone.

6,19-Methanoprogesterone (4) was synthesized in nine steps from the readily available 3 beta,20 beta-diacetyloxy-5 alpha-bromo-6,19-oxidopregnane (5) in 14% overall yield. The additional carbon atom was introduced by reaction of a C-19 aldehyde with Ph3PCHOCH3 under salt free conditions and subsequent hydrolysis to give the homologous aldehyde. Intramolecular addition of the newly incorporated carbonyl (C-19a) to the olefinic C-6 in ring B was achieved by means of a Prins reaction with TiCl4 as Lewis acid.