Synthetic studies on statins. Part 1: a short and cyanide-free synthesis of atorvastatin calcium via an enantioselective aldol strategy
摘要:
A short and cyanide-free enantioselective synthesis of atorvastatin calcium has been achieved starting from a commercially available highly substituted 1,4-diketone in an overall yield of 40%. The key step in this approach is the asymmetric aldol reaction of an aldehyde with diketene in the presence of Ti(O-i-Pr)(4)-Schiff base complex to create the (5R)-stereochemistry of atorvastatin calcium. (C) 2013 Elsevier Ltd. All rights reserved.
3-NITROPROPANAL, 3-NITROPROPANOL, AND 3-NITROPROPANAL DIMETHYL ACETAL
作者:Griesser、Öhrlein、Schwab、Ehrler、Jäger、Davidson, James P.、Martin, Stephen F.
DOI:10.15227/orgsyn.077.0236
日期:——
Convergent Synthesis of a 5HT<sub>7</sub>/5HT<sub>2</sub> Dual Antagonist
作者:Jimmy T. Liang、Xiaohu Deng、Neelakandha S. Mani
DOI:10.1021/op2001194
日期:2011.7.15
The development of an efficient and convergent route to 3-(4-fluorophenyl)-2-isopropyl-2,4,5,6,7,8-hexahydropyrazolo[3,4-d]azepine (1), a potent 5HT(7)/5HT(2) dual antagonist, is described. Significant features of this route are: (a) a regioselective construction of a tetra-substituted pyrazole 6a by reacting an N-monosubstituted hydrazone 4a with an elaborated nitroolefin 5b and (b) a unique Pd-catalyzed hydrogenation method that carries out the four-step, ring-closing reductive amination sequence in a notable one-pot operation to provide 1 in excellent overall yields.