Oxazoline−Oxazinone Oxidative Rearrangement. Divergent Syntheses of (2<i>S</i>,3<i>S</i>)-4,4,4-Trifluorovaline and (2<i>S</i>,4<i>S</i>)-5,5,5-Trifluoroleucine
作者:Julie A. Pigza、Tim Quach、Tadeusz F. Molinski
DOI:10.1021/jo900654y
日期:2009.8.7
Stereoselective syntheses of the valuable fluorinated amino acids (2S,3S)-4,4,4-trifluorovaline and (2S,4S)-5,5,5-trifluoroleucine have been achieved starting from 4,4,4-trifluoro-3-methylbutanoic acid by using a conceptually simple transformation: conversion to a chiral oxazoline, SeO2-promoted oxidative rearrangement to the dihydro-2H-oxazinone, and face-selective hydrogenation of the C=N bond, followed by hydrogenolysis-hydrolysis. The transformation is limited by the tendency of the intermediate beta-trifluoromethyldihydrooxazinone to undergo imine-enamine isomerization. Both amino acids were obtained as configurationally pure hydrochloride salts identical in all respects with those in literature reports,
Non-racemic hexafluoreleucine, and methods of making and using it
申请人:——
公开号:US20040138493A1
公开(公告)日:2004-07-15
One aspect of the invention relates to hexafluoroleucine and congeners thereof, and methods of making the compounds. Another aspect of the nvention relates to the synthesis of protein cores comprising hexafluoroleucine and congeners thereof. Certain peptides comprising hexafluorleucine and congeners thereof have been characterized using comparative biophysical studies. In general, the fluorinated peptides show higher thermal stability and enhanced resistance to chemical denaturation. Further, mixed hydrocarbonfluorocarbon cores self-sort into homogeneous bundles, suggesting new avenues for the design and manipulation of protein-protein interfaces.
An Intrinsic Hydrophobicity Scale for Amino Acids and Its Application to Fluorinated Compounds
作者:Waldemar Hoffmann、Jennifer Langenhan、Susanne Huhmann、Johann Moschner、Rayoon Chang、Matteo Accorsi、Jongcheol Seo、Jörg Rademann、Gerard Meijer、Beate Koksch、Michael T. Bowers、Gert von Helden、Kevin Pagel
DOI:10.1002/anie.201813954
日期:2019.6.11
values gained from different techniques, and their relative ranking, is not straightforward, as the interactions between the environment and the aminoacid are unique to each method. Here, we overcome this limitation by studying the properties of aminoacids in the clean‐room environment of the gas phase. In the gas phase, entropic contributions from the hydrophobic effect are by default absent and only