7,5-融合的氮杂双环烷骨架在内酰胺环的C3位置带有一个立体立体中心,可以作为有效的反向模拟,并已被证明是制备基于Arg-Gly-Asp(RGD)的环五肽的有用中间体(的cRGD)以纳摩尔活性α v β 3 /α v β 5整联蛋白拮抗剂。在这里,我们报告了新的氮杂双环烷骨架的合成,该骨架在C6位具有对位取代的苯乙基侧链,可用于获得基于cRGD的生物结合物,这些结合物可能在抗癌治疗中有希望的应用。通过在苯乙烯衍生物的存在下进行多米诺交叉烯炔复分解/闭环复分解(CEYM / RCM),然后对二烯系统进行催化加氢,我们可以轻松地将二肽前体转化为所需的C6官能化的氮杂双环烷烃骨架。脱保护后,可以利用在苯乙烯部分上适当保护的对氨基的存在,以直接缀合生物活性化合物或在cRGD单元和生物活性化合物之间引入合适的间隔基。
7,5-融合的氮杂双环烷骨架在内酰胺环的C3位置带有一个立体立体中心,可以作为有效的反向模拟,并已被证明是制备基于Arg-Gly-Asp(RGD)的环五肽的有用中间体(的cRGD)以纳摩尔活性α v β 3 /α v β 5整联蛋白拮抗剂。在这里,我们报告了新的氮杂双环烷骨架的合成,该骨架在C6位具有对位取代的苯乙基侧链,可用于获得基于cRGD的生物结合物,这些结合物可能在抗癌治疗中有希望的应用。通过在苯乙烯衍生物的存在下进行多米诺交叉烯炔复分解/闭环复分解(CEYM / RCM),然后对二烯系统进行催化加氢,我们可以轻松地将二肽前体转化为所需的C6官能化的氮杂双环烷烃骨架。脱保护后,可以利用在苯乙烯部分上适当保护的对氨基的存在,以直接缀合生物活性化合物或在cRGD单元和生物活性化合物之间引入合适的间隔基。
Enantioselective quaternization of 4-substituted oxazol-5-(4H)-ones using recoverable Cinchona-derived dimeric ammonium salts as phase-transfer organocatalysts
Dimeric anthracenyldimethyl-derived Cinchona ammoniumsalts are used as chiral organocatalysts (5 mol %) for the enantioselective 4-alkylation of 4-substituted azlactones. The corresponding adducts bearing a new quaternary center were obtained with up to 80% ee when using a dimericammonium salt derived from cinchonidine, and are precursors of α,α-disubstituted α-amino acids. The catalysts can be recovered
Enantiomerically enriched .alpha.,.alpha.-distributed amino acids and
申请人:Board of Trustees of Leland Stanford Junior University
公开号:US06130337A1
公开(公告)日:2000-10-10
Compositions and methods for the preparation of enantiomerically enriched .alpha.,.alpha.-disubstituted amino acid precursors are presented. Briefly, allylic electrophiles are alkylated with oxazolones in the presence of a base and catalytic quantities of a transition metal complex incorporating a chiral phosphine ligand to yield 4,4-disubstituted-5(4H)-oxazolones. These precursors may be subsequently transformed either synthetically or enzymatically to yield enantiomerically enriched .alpha.,.alpha.-disubstituted amino acids.
BEMP-Promoted C(4)-Alkylation of 4-Alkyloxazol-5(4H)-ones: A Rapid and Efficient Route to α,α-Dialkyl-α-amino Acids
作者:Byeong-Seon Jeong、Yeon-Ju Lee、Jeyoung Seo、Dong-Guk Kim、Hyeung-geun Park
DOI:10.1055/s-0032-1317801
日期:——
Rapid and efficient C(4)-alkylation of 4-alkyloxazol-5(4H)-ones has been achieved by the utilization of BEMP as base. 4,4-Dialkyloxazol-5(4H)-ones, which can easily be hydrolyzed into free alpha,alpha-dialkyl-alpha-amino acids, were obtained in high yields (up to 99%) within a few minutes (1-18 min). BEMP, a sterically hindered strong base with low nucleophilicity facilitated the desired reaction, while decreasing the rate of side reactions such as O-alkylation, C(2)-alkylation and the breakage of oxazolone.
Kuebel,B. et al., Chemische Berichte, 1979, vol. 112, p. 128 - 137
作者:Kuebel,B. et al.
DOI:——
日期:——
THE PREPARATION OF ENANTIOMERICALLY ENRICHED OXAZOLONES AND ALPHA, ALPHA-DISUBSTITUTED AMINO ACIDS
申请人:THE BOARD OF TRUSTEES OF
THE LELAND STANFORD JUNIOR UNIVERSITY