The Use of 2-Bornanethiol for the Asymmetric Synthesis of Amines

The proposal to synthesize a camphor sulfinamide reagent using 2-bornanethiol was initiated. A novel disulfide for the synthesis of the reagent was produced through inexpensive means via three synthetic steps. Readily available (+)-camphor underwent thionation using phosphorous pentasulfide in excess. The resulting thiocamphor was reduced to camphor thiol (or 2-bornanethiol) and oxidized to yield camphor disulfide. Further investigation of the disulfide is necessary for confirmation and characterization. Oxidation followed by reaction of the purified sample of this product with ammonia and lithium amide could give camphor sulfinamide. It was determined that purification at the end of each step would help to give better results and cleaner NMR spectra to analyze. Limitations included difficulty with keeping reactions under dry conditions as well as large amounts of time required to run each reaction. From here, the purified disulfide will be used to synthesize camphor sulfinamide which could then be combined with chiral aldehydes and ketones to yield imines in high selectivity

The University of Maryland McNair Scholars Undergraduate Research Journal, Volume 2

The McNair Scholars Undergraduate Research Journal is a collection of abstracts and papers written by McNair scholars at the University of Maryland (http://www.aap.umd.edu/mcnairprogram.html). This issue features papers from the summer 2009 research institute written by participants from the University of Maryland, College Park; Frostburg State University; and Saint Mary's College of Maryland

The Synthesis of Modified Peptide Isosteres As Potential Anti-Parasite Drugs

Protease enzymes are responsible for the catalytic hydrolysis of peptides and therefore play vital roles in the biochemistry of organisms. Serine proteases, which achieve proteolytic cleavage by a mechanism involving an activated serine residue, are numerous in mammalian systems while only a limited number of the analogous cysteine proteases are to be found. Cysteine protease enzymes are however, widespread in parasitic species and often essential to the functioning of the organism. Thus the use of inhibitors for the treatment of parasitic infestation may be possible if the subtle differences between these two enzyme families can be exploited

Insecticide, Acaricide, Repellent and Antimicrobial Development

The present book, a reprint of the Molecules Special Issue "Insecticide, Acaricide, Repellent and Antimicrobial Development", presents key advances in the development of effective and eco-friendly insecticides, acaricides, repellents, and antimicrobials, including products of natural origin

New stereoselective approaches to highly substituted pyrrolidines.

In studies towards the synthesis of substituted pyrroles, the Knight group have adapted an aldol reaction, originally developed by Kazmaier, as a highly diastereoselective method for the synthesis of the cyclisation precursors. Both acetylenic and a,b-unsaturated aldehydes have been successfully utilised in this reaction to afford a variety of b-hydioxy-a-amino ester precursors. This project centred around establishing the optimum conditions for the iodocyclisations of these precursors, and highly substituted pyrrolidines were obtained in the majority of cases. Also it was noted that these aldol adducts were structurally similar to Sphingosine, and via a series of selective reductions, a formal diastereoselective synthesis of Sphingosine was accomplished. In addition, silver-nitrate catalysed 5-endo-dig cyclisations were also applied towards the total synthesis of both Preussin and Codonopsinine. Finally, studies were conducted to establish the selectivity of 5-exo-trig cyclisations in the synthesis of iodo-lactones, and using this methodology, the piperidine core of Pseudodistomin was successfully synthesised

Antioxidant and DPPH-Scavenging Activities of Compounds and Ethanolic Extract of the Leaf and Twigs of Caesalpinia bonduc L. Roxb.

Antioxidant effects of ethanolic extract of Caesalpinia bonduc and its isolated bioactive compounds were evaluated in vitro. The compounds included two new cassanediterpenes, 1α,7α-diacetoxy-5α,6β-dihydroxyl-cass-14(15)-epoxy-16,12-olide (1)and 12α-ethoxyl-1α,14β-diacetoxy-2α,5α-dihydroxyl cass-13(15)-en-16,12-olide(2); and others, bonducellin (3), 7,4’-dihydroxy-3,11-dehydrohomoisoflavanone (4), daucosterol (5), luteolin (6), quercetin-3-methyl ether (7) and kaempferol-3-O-α-L-rhamnopyranosyl-(1Ç2)-β-D-xylopyranoside (8). The antioxidant properties of the extract and compounds were assessed by the measurement of the total phenolic content, ascorbic acid content, total antioxidant capacity and 1-1-diphenyl-2-picryl hydrazyl (DPPH) and hydrogen peroxide radicals scavenging activities.Compounds 3, 6, 7 and ethanolic extract had DPPH scavenging activities with IC50 values of 186, 75, 17 and 102 μg/ml respectively when compared to vitamin C with 15 μg/ml. On the other hand, no significant results were obtained for hydrogen peroxide radical. In addition, compound 7 has the highest phenolic content of 0.81±0.01 mg/ml of gallic acid equivalent while compound 8 showed the highest total antioxidant capacity with 254.31±3.54 and 199.82±2.78 μg/ml gallic and ascorbic acid equivalent respectively. Compound 4 and ethanolic extract showed a high ascorbic acid content of 2.26±0.01 and 6.78±0.03 mg/ml respectively.The results obtained showed the antioxidant activity of the ethanolic extract of C. bonduc and deduced that this activity was mediated by its isolated bioactive compounds