Probing the Efficiency of N-Heterocyclic Carbene Promoted O- to C-Carboxyl Transfer of Oxazolyl Carbonates
摘要:
Screening of a range of azolium salts, bases and solvents for reactivity indicates that triazolinylidenes, generated in situ with KHMDS in THF, promote the Steglich rearrangement of oxazolyl carbonates with high catalytic efficiency (typical reaction time 5 min at < 1.5 mol % NHC). This protocol shows wide substrate applicability, even allowing the efficient generation of vicinal quaternary centers. An improved experimental procedure is also described that allows a simplified one-pot reaction protocol to be employed with similarly high catalytic efficiency.
Design, synthesis and cytotoxicity of novel 3′-N-alkoxycarbonyl docetaxel analogs
摘要:
By-product 9a exhibited potent cytotoxicity against both SK-OV-3 and A549 cell lines. The structure of 9a was characterized using 1D and 2D NMR experiments and confirmed by synthesis to afford a diastereomeric mixture (16a) that was identical to 9a, as well as a pair of diastereomers (R)-16b and (S)-16c. The preliminary SAR study demonstrated that analogs with an (R)-configuration were slightly more potent than analogs with an (S)-configuration. In addition, alpha, alpha-gem-dimethyl analogs 16g-i were the most potent analogs in this series, exhibiting similar potency to docetaxel and greater potency than Taxol against the SK-OV-3 cell line. For the A549 cell line, analogs 16g-i were more potent (>65-fold) than both docetaxel and Taxol. (C) 2013 Elsevier Ltd. All rights reserved.
Novel peptides as NS3-serine protease inhibitors of hepatitis C virus
申请人:——
公开号:US20030216325A1
公开(公告)日:2003-11-20
The present invention discloses novel compounds which have HCV protease inhibitory activity as well as methods for preparing such compounds. In another embodiment, the invention discloses pharmaceutical compositions comprising such compounds as well as methods of using them to treat disorders associated with the HCV protease.
Compounds of Formula (I): wherein n, m, p, q, Y, R1, R2, R3a, R3b, R4, R5, and R6 are as defined herein and their pharmaceutical compositions and methods of use are disclosed.
The present invention provides, for example, an oligonucleotide derivative or a salt thereof comprising a circular oligonucleotide and a linear oligonucleotide, wherein the circular oligonucleotide and the linear oligonucleotide have base sequences complementary to each other, and form a complex via a hydrogen bond between the complementary base sequences, and a method for producing the same.
The present invention is to provide a method for producing a peptide containing an N-alkylamino acid, which comprises the following Steps (1) to (3). Step (1): a step of mixing an N-terminal protected amino acid or an N-terminal protected peptide with a carboxylic acid halide or a halogenated alkyl formate; Step (2): a step of mixing an amino acid or a peptide in which the N-terminal and the C-terminal are not protected with a trialkylsilylating agent; and Step (3): a step of mixing the product obtained in Step (1) with the product obtained in Step (2).
本发明旨在提供一种生产含有N-烷基氨基酸的多肽的方法,该方法包括以下步骤(1)至(3)。步骤(1):将 N 端受保护的氨基酸或 N 端受保护的肽与羧酸卤化物或卤代烷基甲酸酯混合的步骤; 步骤(2):将 N 端和 C 端未受保护的氨基酸或肽与三烷基硅烷化剂混合的步骤;以及 步骤(3):将步骤(1)中得到的产物与步骤(2)中得到的产物混合的步骤。