Methanesulfonic Acid → HCID 21521870, compound

Reaction equation

[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[CH2:9][CH:8]([C@H:13]1[C@:17]([CH3:22])([CH2:18][C:19]([OH:21])=[O:20])[C@@H:16]([OH:23])[CH2:15][CH2:14]1)[CH2:7][CH2:6]2.[CH:24]([O:26][CH2:27][CH2:28][CH2:29][CH3:30])=[CH2:25].CS(O)(=O)=O>C1COCC1>[CH2:27]([O:26][CH:24]([O:23][CH:16]1[CH2:15][CH2:14][CH:13]([CH:8]2[CH2:7][CH2:6][C:5]3[C:10](=[CH:11][CH:12]=[C:3]([O:2][CH3:1])[CH:4]=3)[CH2:9]2)[C:17]1([CH3:22])[CH2:18][C:19]([O:21][CH:24]([O:26][CH2:27][CH2:28][CH2:29][CH3:30])[CH3:25])=[O:20])[CH3:25])[CH2:28][CH2:29][CH3:30]

Participants

Procedure

Contacting (1S, 2S, 5S) -5-(1,2,3,4 -tetrahydro-6-methoxy-2-naphthyl)-2-hydroxy-1-methylcyclopentaneacetic acid with butyl vinyl ether in THF containing methanesulfonic acid affords the stereochemically corresponding α-butoxyethyl 2-(α-butoxyethoxy)-5-(1,2,3,4-tetrahydro-6-methoxy-2-naphthyl)-1 -methylcyclopentaneacetate, in which the ester linkage is cleaved and the carboxyl reduced to hydroxy by contacting with lithium tetrahydroaluminate (1-) in THF. From the resultant alcohol, on esterification with acid chloride or anhydride in pyridine, followed by cleavage of the ether linkage via hydrochloric acid in acetone, the corresponding mono ester of the invention wherein the ester grouping is on the ethanolic side chain eventuates. Contacting such a mono ester with acid chloride or anhydride affords a di-ester of the invention.