196703-87-4Relevant academic research and scientific papers
Process research of (R)-cyclohexyl lactic acid and related building blocks: A comparative study
Storz, Thomas,Dittmar, Peter,Fauquex, Pierre Francois,Marschal, Philippe,Lottenbach, Willy Urs,Steiner, Heinz
, p. 559 - 570 (2013/09/05)
(S)-Cyclohexyl lactic acid is a component of the selective E-selectin inhibitor 2 ((S)-cHexLact-2-0-(3-Galβ(1→3)ddGlc-(4→1)αFuc). We describe the evaluation of various synthetic routes to this building block: (A) diazotation of phenylalanine followed by phenyl ring hydrogenation; (B) phenyl ring hydrogenation of phenyl alanine followed by diazotation; (C) acidic hydrolysis of the cyanohydrin derived from phenylacetaldehyde, enantiomeric resolution of the resulting, racemic phenyl lactic acid via diasteromeric salt formation and phenyl ring hydrogenation; (D) enantioselective dihydroxylation of a cinnamate ester, followed by hydrogenation of the benzylic hydroxy group and the aromatic nucleus; (E) enantioselective biocatalytic reduction of phenylpyruvic acid, followed by phenyl ring hydrogenation. The development of (2R)-2-0-(4-nitrophenyl)sulfonyl-cyclohexyl lactic acid p-bromobenzylester 21 as a buidling block with improved crystallinity and stability is also described.
Regioselective and stereoselective nucleophilic ring opening reactions of a phenyl-substituted aziridine: Enantioselective synthesis of β-substituted tryptophan, cysteine, and serine derivatives
Xiong, Chiyi,Wang, Wei,Cai, Chaozhong,Hruby, Victor J.
, p. 1399 - 1402 (2007/10/03)
The asymmetric synthesis of β-phenyl-substituted cysteine, tryptophan, and serine derivatives was successfully developed. In this approach, the key intermediate, enantiomerically pure 3-phenylaziridine-2-carboxylic ester 7, was prepared from α,β-unsaturated ester 1 by employing the Sharpless asymmetric dihydroxylation. The aziridine 7 was treated with 4-methoxybenzylthiol, indole, and acetic acid to give β-phenyl-substituted cysteine, tryptophan, and serine, respectively, in a clean SN2 type ring opening at the C3 position. This general approach can be used to synthesize a variety of β-substituted novel amino acids.
A general asymmetric synthesis of syn- and anti-beta-substituted cysteine and serine derivatives.
Xiong, Chiyi,Wang, Wei,Hruby, Victor J
, p. 3514 - 3517 (2007/10/03)
A stereodivergent synthetic route has been developed to make the optically pure anti- and syn-beta-substituted cysteine and serine derivatives. In this approach, the key intermediates, > 94% enantiomerically pure cyclic sulfates 3 and aziridines 7, were prepared from alpha,beta-unsaturated esters 1, employing the Sharpless asymmetric dihydroxylation. The high regio- and stereoselective ring-opening reactions of cyclic sulfates and aziridines provided enantiomerically pure beta-substituted cysteine and serine derivatives.
Asymmetric dihydroxylation onto the α,β-unsaturated carboxylic ester derivatives of camptothecin
Tagami, Keiko,Takagi, Shuzo,Sano, Shigeki,Shiro, Motoo,Nagao, Yoshimitsu
, p. 1663 - 1669 (2007/10/03)
Dihydroxyalkanoic ester derivatives (4a,b) and (5a,b) of 20S-camptothecin (1) were diastereoselectively synthesized by exploiting osmium-catalyzed asymmetric dihydroxylation based on the Sharpless procedure. The absolute configuration of the newly formed
