Thermal Weapon Sight (TWS) AN/PAS-13 diffractive optics designed for producibility

The Thermal Weapon Sight (TWS) program is a manportable 3-5 micrometer forward-looking-infrared (FLIR) rifle sight. The manportable nature requires that the optics modules be lightweight, low cost and compact while maximizing performance. These objectives were met with diffractive optics. TWS promises to be the first FLIR sensor to incorporate kinoform surfaces in full scale production

Alkaloids from single skins of the Argentinian toad Melanophryniscus rubriventris (ANURA, BUFONIDAE): An unexpected variability in alkaloid profiles and a profusion of new structures

GC-MS analysis of single-skins of ten Melanophryniscus rubriventris toads (five collections of two toads each) captured during their breeding season in NW Argentina has revealed a total of 127 alkaloids of which 56 had not been previously detected in any frog or toad. Included among these new alkaloids are 23 new diastereomers of previously reported alkaloids. What is particularly distinguishing about the alkaloid profiles of these ten collections is the occurrence of many of the alkaloids, whether known or new to us, in only one of the ten skins sampled, despite two skins being obtained from each breeding site of the five populations. Many of the alkaloids are of classes known to have structures with branched-chains (e.g. pumiliotoxins and tricyclic structures) that are considered to derive from dietary mites. A large number of previously reported and new alkaloids are also of unclassified structures. Only a very few 3,5-disubstituted-indolizidine or -pyrrolizidine alkaloids are observed that have a straight-chain carbon skeleton and are likely derived from ant prey. The possible relationship of these collections made during the toad’s brief breeding episodes to sequestration of dietary arthropods and individual alkaloid profiles is discussed.Fil: Garraffo, H. Martin. Laboratorio de Bioorganic Chemistry; Estados UnidosFil: Andriamaharavo, Nirina R.. Laboratorio de Bioorganic Chemistry; Estados UnidosFil: Vaira, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentina. Universidad Nacional de Jujuy. Facultad de Ingeniería; ArgentinaFil: Quiroga, Maria Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Jujuy. Universidad Nacional de Jujuy. Centro de Investigaciones y Transferencia de Jujuy; ArgentinaFil: Heit, Cecilia Inés. Laboratorio de Análisis de Residuos y Trazas; ArgentinaFil: Spande, Thomas F.. Laboratorio de Bioorganic Chemistry; Estados Unido

Two-directional synthesis and biological evaluation of alkaloid 5-epi-cis-275B′

The first total synthesis of myrmicine ant alkaloid 5-epi-cis-275B0 (4) is presented. A tandem cyclisation stablished the entire core of the structure in a single transformation as well as the required 2,5-anti stereochemistry. Two-directional synthesis was used to furnish the cyclisation precursor 2, as in each of the subsequent steps towards the natural product. The first electrophysiology studies for 4 (against nicotinic acetylcholine receptors) were also conducted, finding modest inhibition of current

Synthesis and in vitro antiproliferative activity of novel (4-chloro- and 4-acyloxy-2-butynyl)thioquinolines

The series of new acetylenic thioquinolines containing propargyl, 4-chloro-2-butynyl, and 4-acyloxy-2-butynyl groups have been prepared and tested for antiproliferative activity in vitro against human [SW707 (colorectal adenocarcinoma), CCRF/CEM (leukemia), T47D (breast cancer)] and murine [P388 (leukemia), B16 (melanoma)] cancer lines. Most of the obtained compounds exhibited antiproliferative activity, especially compounds 8, 12, and 21 showed the ID50 values ranging from 0.4 to 3.8 μg/ml comparable to that of cisplatin used as reference compounds

Phenotypic and Genetic Divergence among Poison Frog Populations in a Mimetic Radiation

The evolution of Müllerian mimicry is, paradoxically, associated with high levels of diversity in color and pattern. In a mimetic radiation, different populations of a species evolve to resemble different models, which can lead to speciation. Yet there are circumstances under which initial selection for divergence under mimicry may be reversed. Here we provide evidence for the evolution of extensive phenotypic divergence in a mimetic radiation in Ranitomeya imitator, the mimic poison frog, in Peru. Analyses of color hue (spectral reflectance) and pattern reveal substantial divergence between morphs. However, we also report that there is a “transition-zone� with mixed phenotypes. Analyses of genetic structure using microsatellite variation reveals some differentiation between populations, but this does not strictly correspond to color pattern divergence. Analyses of gene flow between populations suggest that, while historical levels of gene flow were low, recent levels are high in some cases, including substantial gene flow between some color pattern morphs. We discuss possible explanations for these observations

62(P-39) Total Synthesis of Dart-Poison Frog Alkaloids 223A, 205B, 207I, 223I

A remarkably diverse array of biologically active alkaloids, for example, blockers of neuromuscular-type, ganglionic-type, and nicotinic receptor channels, occurs in amphibian skin, and over 500 alkaloids have been isolated to date. The structural diversity and pharmacological activity associated with these alkaloids have stimulated research in numerous synthetic groups. Among them, we achieved the first synthesis of the alkaloids 223A has been accomplished, the proposed structure has been revised, and the relative stereostructure of natural 223A was determined. We have demonstrated the first enantioselective total synthesis of the antipode of structurally unique alkaloid 205B, and the absolute stereochemistry of natural 205B has been determined to be 2aR, 5aR, 6S, 8S, 8aR. Furthermore, we achieved the chiral synthesis of quinolizidine 207I and its absolute stereochemistry was determined to be 1S, 4S, 10S by the GC-coinjection analysis of racemic compound and natural product. Finally, we also achieved the synthesis of both stereoisomers for the alkaloid 223I, and the determination of the ralative stereochemistry of natural 223I using GC-coinjection analysis of these isomers and natural product is now under investigations

Approaches to analogs of anhydrogliotoxin

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