The condensationreaction of formaldehyde with glycine or glycine Schiff bases co-ordinated to CoIII, CuII, and NiII has been studied. The reaction leads invariably to α-hydroxymethylserine. The influence of the metalion, the charge of the complex, pH, and the ratio of the reactants are discussed, together with the effect of Schiff-base formation. With [Cu(glyO)2](glyO = glycinate) the condensation
control postprandial hyperglycemia. In this study, a series of phenolic acids with the L-amino acid moiety were synthesized and their inhibitory activities against α-glucosidase from Saccharomyces cerevisiae (EC 3.2.1.20) were evaluated. The results suggested that all these compounds showed strong α-glucosidase inhibitory activities. In particular, N-(4-hydroxyl-phenylpropenoyl)-L-alanine (c2) and N-
2,2-Difluoro-1,3,2-oxazaborolidin-5-ones 1, which are synthesized
from BF3 and salts of amino acids, are highly effective,
convenient and, moreover, inexpensive intermediates for the simultaneous
protection of both α-amino and α-carboxy groups in
α-amino acids. The new method streamlines the hitherto tedious
procedures for side-chain protection of Ser and Thr.
Ser(But),
Thr(But), Ser(Bzl) and Thr(Bzl) are obtained
by this procedure in high yields and in pure form using highly reactive
reagents.
Potassium Alkoxide as an Efficient Catalyst for Nucleophilic Perfluoroalkylation: Attempt at Anion-Controlled Enantioselective Insertion of a Trifluoromethyl Group
Potassiumalkoxide was found to be a highly active catalyst for the nucleophilic trifluoromethylation of carbonyl compounds. The catalytic system was successfully applied to the reactions of both aldehydes and ketones, affording the corresponding trifluoromethylated products in high yields at low catalyst loadings (0.1–0.01 mol%) in several solvents, such as THF, toluene, and CH2Cl2. In addition, the
发现醇钾是羰基化合物的亲核三氟甲基化的高活性催化剂。该催化体系成功地应用于醛和酮的反应,在 THF、甲苯和 CH 2 Cl 2等几种溶剂中以低催化剂负载量(0.1-0.01 mol%)以高产率提供相应的三氟甲基化产物。此外,含有 ( S )-2,2'-双[双(3,5-二甲基苯基)膦基]-1,1'-联萘 [( S )-XylBINAP]的 Ru(II) 络合物的钾盐配体和两个l原位制备的-苏糖酸盐配体催化芳族醛的对映选择性三氟甲基化,尽管 ee 值不令人满意(小于 20%)。
Der 2-(4-pyridyl)Ethoxycarbonyl-(4-Pyoc)-rest - eine hydrophile, säure- und basenstabile aminoschutzgruppe für die peptidsynthese