(3,3-Difluoroazetidin-1-yl)pip

Two‐Step, One‐Pot Synthesis of Inosine, Guanosine, and 2′‐Deoxyguanosine O6‐Ethers via Intermediate O6‐(Benzotriazol‐1‐yl) Derivatives

) and Cs2 CO3 under a nitrogen atmosphere. Conversion to the O 6 ?(benzotriazol?1?yl) ethers occurs within about 10 min for inosine, and within about 60 min for guanosine and 2??deoxyguanosine. Then, for reaction with alcohols, the reaction mixture

Convenient and Efficient Approach to the Permanent or Reversible Conjugation of RNA and DNA Sequences with Functional Groups

of 3?,5??disilylated 2??O ?(methylthiomethyl)ribonucleosides to 2??O ?(phthalimidooxymethyl)ribonucleosides is achieved in yields of 66% to 94%. Desilylation and dephtalimidation of these ribonucleosides by treatment with NH4 F in MeOH produce 2??O ?aminooxymethylated

环肽的合成方法

3和10倍量DPPA，反应66小时，得到收率仅为3%的纤维蛋白原受体拮抗剂Cyclo（Asp-D-Ser- Phe-D-Phe-Arg-Gly）；若改变NaHCO3和DPPA用量，并且反应过程中用氩气保护，反应三天，可得到产率高达39%的上述环肽。两种条件下所得收率有如此大的差别，主要原因是目的物在碱性条件下易分解。 以DPPA为缩合剂合成环肽时，除了用NaHCO3、Na2CO3为无机碱外，也常使用KH2PO4。例如能够与鸦片受体结合的环肽Try-C[D-A2bu-Phe-Phe-（L or D