The first primary aminocatalytic direct cross-aldol reaction of acetaldehyde is presented. Among the various vicinal diamines screened, the L-tert-leucine derivative 1c in conjunction with (H4SiW12O40)0.25 was identified as the optimal catalyst; good catalytic activity (up to 99 % yield in 4 h), and high enantioselectivities (up to 92 % ee) were achieved for a range of donors, including aromatic aldehydes
Chiral Primary−Tertiary Diamine Catalysts Derived From Natural Amino Acids for <i>syn</i>-Aldol Reactions of Hydroxy Ketones
作者:Jiuyuan Li、Sanzhong Luo、Jin-Pei Cheng
DOI:10.1021/jo802557p
日期:2009.2.20
A series of primary-tertiary diamine catalysts were designed and synthesized from primary natural amino acids. Application of these new chiral catalysts in direct aldol reactions of α-hydroxyketones showed very good catalytic activity (up to 97% yield) and high syn selectivity (up to syn/ anti = 30:1, 99% ee).
从伯天然氨基酸设计合成了一系列伯叔二胺催化剂。这些新的手性催化剂在α-羟基酮的直接醛醇缩合反应中的应用显示出非常好的催化活性(高达97%的收率)和高的合成选择性(高达syn / anti = 30:1,99%ee)。
Studies on analgesic oligopeptides. V. Structure-activity relationship of tripeptide alkylamides, Tyr-D-Arg-Phe-X.
Twenty-one analogs based on the structure Tyr-D-Arg-Phe-X (X=OH, alkyl ester, alkylamide or amino acid having a different carbon chain) were synthesized by the solution method and their analgesic activities were tested after subcutaneous (s. c.) administration in mice. Most tripeptide alkylamides showed no analgesia at a dose of 10 mg/kg, s. c. However, some tripeptide alkylamides having the hydroxyl group on the alkyl moiety showed greater activity than morphine. Introduction of the carboxyl group on the alkyl moiety also led to tetrapeptide analogs with potent analgesia, e. g., the compound with X=β-alanine is 33 times more potent than morphine on a molar basis. These results suggest that proper carbon chain lengths and the presence of an oxygen atom at the fourth position are important for high analgesic activity in the series of D-Arg2-dermorphin analogs.
Cytotoxic Activity of Synthetic Chiral Amino Acid Derivatives
作者:Pedro de Castro、Raoni Siqueira、Luiza Conforte、Chris Franco、Gustavo Bressan、Giovanni Amarante
DOI:10.21577/0103-5053.20190157
日期:——
series of dual-protected aminoacidderivatives was synthesized and evaluated as potential novel anticancer agents. The 40 derivatives were prepared in up to three reaction steps. The cytotoxic activities were screened in vitro against a panel of tumor and nontumor cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Among the synthesized derivatives, three of them showed
Enantioselective Addition of Vinylzinc Reagents to Aldehydes Catalyzed by Modular Ligands Derived from Amino Acids
作者:Meaghan L. Richmond、Christopher M. Sprout、Christopher T. Seto
DOI:10.1021/jo051313l
日期:2005.10.1
enantioselectivities that ranged from 52 to 91% ee and yields that ranged from 40 to 90%. This ligand was especially effective for the reaction of aromatic aldehydes with vinylzinc reagentsderivedfrom bulky terminal alkynes. Ligand 3d catalyzed the addition of (E)-(3,3-dimethylbut-1-enyl)(ethyl)zinc to 2-naphthaldehyde to give (R,E)-4,4-dimethyl-1-(naphthalene-1-yl)pent-2-en-1-ol in 89% ee. The ee of this