Novel approach to the ansamycin antibiotics macbecin I and herbimycin A. A formal total synthesis of (+)-macbecin I
作者:Stephen F. Martin、Jeffrey A. Dodge、Laurence E. Burgess、Chris Limberakis、Michael Hartmann
DOI:10.1016/0040-4020(95)01107-2
日期:1996.2
The asymmetric syntheses of 25 and 29, which constitutes the C(3)–C(15) segment of the stereochemically complex ansa chain of (+)-macbecin I (1) and herbimycin A (2), respectively, have been achieved. The approach features the furan-hydropyranone transformation 9→10 followed by stereoselective introduction of substituents onto the conformationally-biased hydropyran ring of 10 to give 17. Extension
What is disclosed are growth hormone secretagogues, and their uses, of the formula
wherein R1 is C6H5CH2OCH2—, C6H5 (CH2)3— or indol-3-ylmethyl; Y is pyrrolidin-1-yl, 4-C1-C6 alkylpiperidin-1-yl or NR2R2; R2 are each independently a C1 to C6 alkyl; R3 is 2-napthyl or phenyl para-substituted by W; W is H, F, CF3, C1-C6 alkoxy or phenyl; and R4 is H or CH3,
or a pharmaceutically acceptable salt or solvate thereof.
New strategy for the synthesis of the taxane diterpenes: Formation of the BC-rings of taxol via a [5+2]-pyrylium ylide-alkene cyclization, ring expansion strategy
The BC-rings of taxol can be synthesized using an intramolecular [5+2]-pyrylium ylide-alkene cyclization, followed by gem-methylcyclopropanation and reductive cleavage of the internal cyclopropane bond.
Ruthenium-promoted diaryl ether synthesis in the construction of the F-O-G ring system of a teicoplanin model
作者:Anthony J Pearson、Philippe O Belmont
DOI:10.1016/s0040-4039(00)00030-7
日期:2000.3
An end-game approach is described for the synthesis of glycopeptide antibiotics related to teicoplanin, using ruthenium-promoted diaryl ether formation, followed by cycloamidation.
描述了使用钌促进的二芳基醚形成,然后进行环酰胺化合成与替考拉宁有关的糖肽抗生素的最终方法。
Synthesis of chiral alkynes having 2H or halogen at the secondary or tertiary propargylic stereogenic center by hydrolysis and halogenolysis of optically active allenyltitaniums having axial chirality
作者:Duk Keun An、Sentaro Okamoto、Fumie Sato
DOI:10.1016/s0040-4039(98)00830-2
日期:1998.6
The hydrolysis and halogenolysis of opticallyactive allenyltitaniums, generated by the reaction of a reagent with opticallyactive propargyl alcohol derivatives, proceed in a regioselective way and with excellent degree of chiral transfer, thus opening up a highly efficient and practical route to chiral alkynes having 2H or Cl at the stereogenic propargylic center.