نتایج جستجو برای: protected α amino acid
تعداد نتایج: 1010754 فیلتر نتایج به سال:
The highly α-selective and scalable synthesis of the Fmoc-protected GalNAc-threonine amino acid and TN antigen in gram scale (0.5-1 g) is described. The challenging 1,2-cis-2-amino glycosidic bond is addressed through a coupling of threonine residues with C(2)-N-ortho-(trifluoromethyl)benzylidenamino trihaloacetimidate donors mediated by Ni(4-F-PhCN)4(OTf)2. The desired 1,2-cis-2-amino glycosid...
sulfuric acid {[3-(3-silicapropyl)sulfanyl]propyl}ester (saspspe) is employed as a recyclable catalyst for the synthesis of α-amino nitriles. these syntheses were performed via a one-pot three-component condensation of aldehydes, amines, and trimethylsilyl cyanide under mild reaction conditions at room temperature. the catalyst could be recycled and reused several times without any loss of effi...
α-Amino nitriles are synthesized in a one-pot, three-component coupling of aldehydes (or ketones), aniline, and trimethylsilyl cyanide using a catalytic amount of choline chloride.2ZnCl2 as a bio Lewis acidic ionic liquid. Mild Lewis acidic characteristic of this ionic liquid allows efficient synthesis of α-amino nitriles from acid sensitive aldehydes.
A suitably protected Orn-derived (3S,4S)-β-lactam was used as common intermediate in the synthesis of conformationally constrained (3S,4S)-2-oxoazepane α,α- and (2S,3S)-2-oxopiperidine-β(2,3,3)-amino acid derivatives. Compared to alternative procedures using an N-p-methoxybenzyl group at the 2-azetidinone, the incorporation of a p-methoxyphenyl moiety is crucial for the excellent stereochemical...
α-Amino nitriles are synthesized in a one-pot, three-component coupling of aldehydes (or ketones), aniline, and trimethylsilyl cyanide using a catalytic amount of choline chloride.2ZnCl2 as a bio Lewis acidic ionic liquid. Mild Lewis acidic characteristic of this ionic liquid allows efficient synthesis of α-amino nitriles from acid sensitive aldehydes.
An effective protocol toward the O-arylation of β-hydroxy-α-amino acid substrates serine and threonine has been developed via Chan-Lam cross-coupling. This Cu(II)-catalyzed transformation involves benign open-flask conditions that are well-tolerated with a variety of protected (Boc-, Cbz-, Tr-, and Fmoc-) serine and threonine derivatives and various potassium organotrifluoroborates and boronic ...
Quorum sensing controls the luminescence of Vibrio fischeri through the transcriptional activator LuxR and the specific autoinducer signal produced by luxI. Amino acid sequences of these two genes were analyzed using bioinformatics tools. LuxI consists of 193 amino acids and appears to contain five α-helices and six ß-sheets when analyzed by SSpro8. LuxI belongs to the autoinducer synthetase fa...
An enantioselective method for Pd(II)-catalyzed cross-coupling of methylene β-C(sp(3))-H bonds in cyclobutanecarboxylic acid derivatives with arylboron reagents is described. High yields and enantioselectivities were achieved through the development of chiral mono-N-protected α-amino-O-methylhydroxamic acid (MPAHA) ligands, which form a chiral complex with the Pd(II) center. This reaction provi...
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