1. The activity of chicken pepsin was partially inhibited by dimethyl-(2-hydroxy-5-nitrobenzyl)sulphonium bromide, but was unaffected by p-bromophenacyl bromide. 2. In the presence of Cu2+, diazoacetylnorleucine methyl ester completely inactivated chicken pepsin with the incorporation of 1 mol/mol. The mechanism of the reaction was similar to that with pig pepsin. 3. Chicken pepsin was complete...

Lactol carbocyclisations provide a succinct method of constructing the oxabicyclo[3.2.1]octane scaffold, motif present in various natural products medicinal interest. Lactols containing an unsaturated ketone or ester were prepared by olefin cross-metathesis; electrophilic alkene derived from methyl vinyl underwent concomitant terminal α-methylenation and oxa-Michael addition to give bridged lac...

In the present work, an attempt has been made to develop high-performance polymeric hybrid binary blends of epoxy/benzoxazine and benzoxazine/cyanate ester with varying weight percentages (25/75, 50/50 75/25 wt%) resins, namely, bisphenol-F epoxy resin (DGEBF), benzoxazines [bisphenol–F/aniline (BF-a) imidazole core-based bisphenol/aniline (IBP-a)] cyanate [bisphenol-F bifunctional (BF-CE)]. Th...

Synthesis of the C(7)-C(20) subunit of amphidinolides C and F has been accomplished utilizing a Me(3)Al-mediated ring opening of a vinyl iodide/allylic epoxide to establish the C(12,13)anti stereochemistry, an organolithium coupling/olefination sequence to construct the C(9)-C(11) diene moiety and a sulfone alkylation/hydroxylation strategy to join the C(7)-C(14) and C(15)-C(20) fragments.

CF(3)-substituted vinyl diphenylsulfonium triflate is an effective annulation reagent for the formation of α-CF(3) substituted, epoxide-fused heterocycles (pyrrolidines, piperidines, and tetrahydrofurans). This simple method affords a variety of valuable heterocyclic building blocks in a highly diastereoselective manner (dr >20:1).

Background and Aim: One of the problems of all ceramic restorations is their risk of fracture due to occlusal loads. The aim of the present study was to compare the effect of two marginal designs (shoulder and chamfer) on the fracture resistance of IPS-emax all ceramic restorations. Materials and Methods: One extracted maxillary first premolar received chamfer 50' marginal preparation (0.8 m...

−− Two different water-borne dispersions (latex) containing different amounts of vinyl acetate and a commercial vinyl ester monomer (VeoVa10) were evaluated by incorporating them in paint formulations for wall protection. Three paint formulations were prepared with different PVC values. The main properties such as hiding power, washability, tension of adhesion, and elasticity were assessed. Cha...

Two strategies for the projected total synthesis of the phenomenally potent antitumour macrolides amphidinolide N (1) and caribenolide I (2) are described. The title compounds are introduced as challenging and unique targets for chemical synthesis, and their retrosynthetic analysis is presented. The synthesis of the four defined key building blocks (10, 39, 67 and 72), required for the construc...

A second-generation synthesis of three structurally related chlorosulfolipids has been developed. Key advances include highly stereocontrolled additions to α,β-dichloroaldehydes, kinetic resolutions of complex chlorinated vinyl epoxide intermediates, and Z-selective alkene cross metatheses of cis-vinyl epoxides. This strategy facilitated the synthesis of enantioenriched danicalipin A, mytilipin...