CH594621

1386146 Prostoglandins IMPERIAL CHEMICAL INDUSTRIES Ltd 5 April 1973 [3 May 1972] 20566/72 Headings C2C and C2P [Also in Division C3] The invention comprises prostaglandins of the Formula I: wherein R1 is CH 2 OH, COOH or C 2-11 alkoxycarbonyl; A is -CH 2 -CH 2 - or trans- CH=CH-; R4 is an aryl, furyl or thienyl radical which is unsubstituted or which is substituted by halogen atoms, nitro, phenyl, halophenyl, C 1-4 alkyl, C 2-4 alkoxyalkyl, C 1-4 haloalkyl, C 1-4 alkoxy, C 1-4 acylamino or di- (C 1-4 alkyl)amino; R2 is OH or C 1-4 alkanoyloxy and R3 is H, or R2 and R3 together form an oxo radical, which compounds contain 0, 1 or 2 C 1-4 alkyl radicals as substituents on carbon atoms 2, 3, or 4, and for those compounds wherein R1 is COOH, pharmaceutically and veterinarily acceptable salts thereof, and their preparation. Compounds of the above formula in which R1 is CH 2 OH are prepared by reducing the corresponding compounds in which R1 is alkoxycarbonyl, which are made by esterifying the corresponding compounds in which R1 is COOH. Those compounds of the above formula in which R1 is COOH, R2 is OH and R3 is H are obtained by reacting (4-carboxybutyl)triphenylphosphonium salts, optionally bearing 0, 1 or 2 alkyl radicals on carbon atoms 2, 3 or 4 with lactols of the Formula II: obtained by reducing the corresponding lactones resulting from the hydrolysis of the appropriate 4α - (4 - phenylbenzoyloxy) - 4# - (3 - hydroxy- 3 - R4- trans - 1 - propenyl) - 3,3aα,4,5,6,6aα- hexahydro - 2H - cyclopenta[b]furan - 2 - ones, obtained by reducing the corresponding 4α-(4- phenylbenzoyloxy) - 4# - (3 - oxo - 3 - R4 - trans- 1 - propenyl) - 3,3aα,4,5,6,6aα - hexahydro - 2H- cyclopenta[b]furan-2-ones, which is prepared by reacting 4α - (4 - phenylbenzoyloxy) - 3,3aα,4,- 5,6,6aα - hexahydro - 2 - oxo - 2H - cyclopenta- [b]furan-4-carbonaldehyde with phosphonates of the formula (CH 3 O) 2 P(+)OCH(-)COR4 or phosphoranes of the formula Ph 3 P : CHCOR4. Compounds of Formula I above in which R2 is OH and R3 is H may be prepared by reducing compounds of the Formula IV: wherein R6 and R7 are OH or protected OH, and, if necessary, removing the protecting groups, the compounds of Formula IV (R1 is COOCH 3 ) being obtained by reacting phosphonates of the formula (CH 3 O) 2 POCH 2 COR4 with methyl [2# - formyl - 3α,5α - di - (hydroxy or protected hydroxy) cyclopent - 1α - yl] hept - 5- cis-enoates. Compounds of the Formula I above in which A is trans-CH=CH- and R1 is COOH may be pr