Microwave Irradiation and Diisopropylcarbodiimide (DIC)/7-Aza-1-hydroxybenzotriazole (HOAt): A Potent Combination for Synthesis of Variuos Hydrazide from N-Protected Amino Acid and Hydrazine
摘要:
我们采用微波反应装置(Synthos 3000 Aton Paar, GmbH,最大磁控管功率1400 W),开发了在二异丙基氨基亚胺(DIC)与1-羟基苯并三唑(HOXt)(X = A 或 B)反应的条件,能够高效地合成氨基酸肼衍生物。通过比较常规加热反应和微波反应的反应时间、反应条件等,发现微波反应更为高效。在二异丙基氨基亚胺(DIC)与1-羟基苯并三唑(HOBt)的反应中产率不如二异丙基氨基亚胺(DIC)与7-氮杂-1-羟基苯并三唑(HOAt)的反应,后者可以获得更好的产率(95-98%)。
我们在此描述了一种使用二异丙基氨基亚胺(DIC)/1-羟基苯并三唑(HOXt)(X = A 或 B)在微波辐射下制备氨基酸肼及肽肼衍生物的快速技术。比较了传统加热与微波辐射的方法。微波方法快速、方便,并在温和条件下进行。二异丙基氨基亚胺(DIC)/7-氮杂-1-羟基苯并三唑(HOAt)所获得的产率(95-98%)和纯度明显优于二异丙基氨基亚胺(DIC)/1-羟基苯并三唑(HOBt)。
PyBOP® and PyBroP: Two reagents for the difficult coupling of the α,α-dialkyl amino acid, Aib.
摘要:
The difficult coupling of alpha-aminoisobutyric acid (Aib) was carried out using PyBOP(R) and PyBroP in a comparative study with BOP and BroP. These reagents gave good results under simple conditions (one pot, r.t., 1 h). Coded amino acids could be coupled with Aib using PyBOP under standard conditions of peptide synthesis without racemization whereas the coupling of two Aib residues required PyBroP/DMAP. A fragment containing an Aib C-terminal could be coupled without epimerization of the penultimate residue.
1-Ethyl 2-Halopyridinium Salts, Highly Efficient Coupling Reagents for Hindered Peptide Synthesis both in Solution and the Solid-Phase
作者:Peng Li、Jie-Cheng Xu
DOI:10.1016/s0040-4020(00)00657-8
日期:2000.10
proved to be very effective for the synthesis of hindered peptides containing N-methylated or Cα,Cα-dialkylated amino acid residues. HPLC monitoring of model reactions indicated that these pyridinium salts demonstrated higher reactivities, lower racemization than the commonly used halogenated uronium and phosphonium salts. The efficiency of these pyridinium type coupling reagents was further proved by the
1-乙基-2-卤代吡啶鎓盐,BEP,FEP,BEPH和FEPH,合成并证明是含有受阻的肽的合成是非常有效的Ñ甲基化的或Ç α,Ç α-二烷基化的氨基酸残基。HPLC对模型反应的监测表明,与通常使用的卤化铀盐和phospho盐相比,这些吡啶鎓盐具有更高的反应活性和更低的消旋性。通过合成一系列受阻的寡肽和活性酯,具有良好的收率和方便的后处理,进一步证明了这些吡啶鎓类偶联剂的效率。使用这些吡啶鎓盐还成功合成了环孢菌素A(CsA)的8-11四肽片段和Dolastatin 15的五肽部分。这些吡啶鎓类偶联剂对SPPS的效率还通过CsA的极受阻碍的8-11肽段和CsO的线性十一肽的固相合成证明。1 H NMR,IR和HPLC。提出主要的反应性中间体是N-保护的氨基酸或肽的相应的酰卤和酰氧基吡啶鎓盐。
Curtin–Hammett and Steric Effects in HOBt Acylation Regiochemistry
作者:Benjamin D. Brink、Justin R. DeFrancisco、Julie A. Hillner、Brian R. Linton
DOI:10.1021/jo200346r
日期:2011.7.1
While hydroxybenzotriazole is commonly used in a variety of bond-forming reactions, its acylation has been shown to produce a regiochemical (O vs N) mixture with complex kinetic behavior. Increased steric bulk on the electrophile favors formation of the oxygen-acylated product. Upon standing as a solid, the mixture can isomerize completely to the nitrogen adduct. An equilibrium ratio of regioisomers
Beta-alanine derivatives and their use as receptor anatgonists
申请人:——
公开号:US20030018193A1
公开(公告)日:2003-01-23
A beta-alanine derivative of the formula (I) wherein R
1
is hydrogen atom or an amino protective group; A is a lower alkylene group or a lower alkenylene group; R
2
is hydrogen atom or an amino group which may be substituted with an acyl group; R
3
is hydrogen atom or an aryl or aralkyl group which may be substituted with one or more of hydroxy and/or lower alkoxy, a moiety represented by the formula (II), which is a bivalent N-containing 6- to 8-membered heterocyclic group, or a pharmaceutically acceptable salt thereof.