3-Benzo[b]furyl- and 3-benzo[b]thienylaminobutyric acids as GABAB ligands. Synthesis and structure-activity relationship studies
摘要:
Baclofen (beta-p-chlorophenyl GABA) is one of the selective agonists for the bicuculline-insensitive GABA(B) receptors. In the search for new compounds that bind to GABA(B) receptors it is very important to clarify the structural requirements. We report the syntheses of and binding studies on various S-heteroaromatic (benzo[b]furan and benzo[b]thiophen)aminobutyric acids. The 4-amino-3-(7-methyl-benzo[b]furan-2-yl)butanoic acid 8g is a potent and specific ligand for GABA(B) receptors, with an IC50 value of 5.4 mu M in the displacement of [H-3]GABA.
Hydroxynitrile lyases (HNLs) catalyze the enantioselective cleavage/formation of cyanohydrins. However, current methods for determining hydrocyanation are not suitable for mass screening of mutants for protein engineering of these biocatalysts. We demonstrate herein a chromogenic high‐throughput screening method for cyanohydrinsynthesis that is validated by either substrate profiling or the directed evolution
benzo-ketal aldehyde which was proved to be resistant against racemization during the deprotection step, with dramatically improved productivity (>95% conversion vs <1%). X-ray structure analysis and kinetic study revealed the side chain of L331 tunes the substrate adaptability of bulky and rigid benzo-ketal aldehyde, thereby facilitating the formation of a series of valuable unnatural cyanohydrins in high
A Homochiral Metal–Organic Framework as an Effective Asymmetric Catalyst for Cyanohydrin Synthesis
作者:Ke Mo、Yuhua Yang、Yong Cui
DOI:10.1021/ja411887c
日期:2014.2.5
A homochiral metal-organic framework (MOF) of an enantiopure 2,2'-dihydroxy-1,1'-biphenyl ligand was constructed. After exchanging one proton of the dihydroxyl group for Li(I) ions, the framework is shown to be a highly efficient and recyclable heterogeneous catalyst for asymmetric cyanation of aldehydes with up to > 99% ee. Compared with the homogeneous counterpart, the MOF catalyst exhibits significantly enhanced catalytic activity and enantioselectivity, especially at a low catalyst/substrate ratio, due to that the rigid framework could stabilize the catalytically active monolithium salt of biphenol against its free transformation to catalytically inactive and/or less active assemblies in reactions. The synthetic utility of the cyanation was demonstrated in the synthesis of (S)-bufuralol (a nonselective beta-adrenoceptor blocking agent) with 98% ee.