Beilstein J. Org. Chem.2016,12, 2234–2239, doi:10.3762/bjoc.12.215
rosaprostol (1), an antiulcer drug, were efficiently synthesized from the enantiomers of 2-(dimethoxyphosphoryl)-3-hexylcyclopentanone (3) as chiral substrates. The latter were obtained by resolution of racemic 3 with (+)-(R)-1-(1-naphthyl)ethylamine. The conversion of (+)-3 into rosaprostol stereoisomer
to 64%. The remaining two stereoisomers, (−)-1b and (+)-1d, were obtained from (−)-1a and (+)-1c in 71 and 68% yield, respectively, by a two-reaction sequence, in which a Mitsunobu inversion of configuration at C-5 was the key step.
Keywords: antiulcer drug; chiral resolution; rosaprostol
; stereoselective synthesis; synthetic design; Introduction
Rosaprostol (1) is a trade name for 7-(2-hexyl-5-hydroxycyclopentane)heptanoic acid (Figure 1) which belongs to a series of 19,20-dinorprostanoic acid derivatives. It exhibits gastric antisecretory activity and cytoprotective action without the undesired
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Graphical Abstract
Figure 1:
Structure of rosaprostol (1) and numbering system.