- Enantioselective synthesis of dihydrofuranylglycine, furanylglycine, furanylalanine and homo-furanylalanine derivatives
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Enantiomerically pure nor-furanomycin, furanylglycine, furanylalanine and homo-furanylalanine derivatives were prepared from appropriate amino acid derived dienes using ring-closing metathesis as the key step. Georg Thieme Verlag Stuttgart.
- Chattopadhyay, Shital K.,Sarkar, Kaushik,Karmakar, Swastik
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- How to spoil the taste of insect prey? A novel feeding deterrent against ants released by larvae of the alder leaf beetle, Agelastica alni
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Chemical defense of leaf beetle larvae (Chrysomelidae) against enemies is provided by secretions containing a wide range of deterrent compounds or by unpalatable hemolymph constituents. Here we report a new, very strong feeding deterrent against ants released by larvae of the alder leaf beetle Agelastica alni when attacked. The larvae release a defensive fluid from openings of pairwise, dorsolaterally located tubercles on the first to the eighth abdominal segments. The fluid, consisting of hemolymph and probably a glandular cell secretion, has previously been shown to contain a very stable, non-volatile feeding deterrent. The major deterrent component was isolated by repeated HPLC separation and analyzed by NMR and MS. The compound proved to be γ-L-glutamyl-L-2-furylalanine (1), a novel dipeptide containing the unusual amino acid L-2-furylalanine. This amino acid, although synthetically well known, has not previously been reported from natural sources. The absolute configuration of the natural compound was elucidated by enantioselective gas chromatography after derivatization. The structure of the dipeptide was verified by the synthesis of several isomeric dipeptides. In bioassays a concentration of 1 μgμL-1 was sufficient to deter polyphagous Myrmica rubra ants from feeding.
- Hilker, Monika,Haeberlein, Christopher,Trauer, Ute,Buennige, Martina,Vicentini, Mark-Oliver,Schulz, Stefan
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p. 1720 - 1726
(2011/04/18)
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- PYRROLIDINONE GLUCOKINASE ACTIVATORS
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Provided herein are compounds of the formula (I): as well as pharmaceutically acceptable salts thereof, wherein the substituents are as those disclosed in the specification. These compounds, and the pharmaceutical compositions containing them, are useful for the treatment of metabolic diseases and disorders such as, for example, type II diabetes mellitus.
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Page/Page column 38
(2009/10/30)
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- Synthesis of Heteroaromatic Thyrotropin-releasing Hormone Analogues
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Novel thyrotropin-releasing hormone (TRH) analogues containing the unnatural and heteroaromatic L-pyrrolylalanine, D-pyrrolylalanine, and L-furylalanine amino acids in position 2 have been synthesised.L-Furylalanine was obtained by the stereospecific hydrolysis of the N-acetyl-D,L-amino acid with acylase I.A protected derivative of D,L-pyrrolylalanine was prepared, the racemate was incorporated into the tripeptide and the LLL and LDL diastereoisomers were separated at the end of the synthesis.
- Bladon, Christine M.
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p. 1151 - 1158
(2007/10/02)
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