about one gram of potassium hydroxide is kept at 25 u00b0 c for 10 hr under nitrogen the solution is then cooled to 10 u00b0 c and neutralized by addition of 3n hydrochloric acid at 10 u00b0 c the resulting solution is extracted repeatedly with ethyl acetate and the combined ethyl acetate extracts are washed with water and then with brine dried and concentrated to yield the formula xvii title compound following the procedure of example 13 each of the 16 or 16 16 di fluoro pge 2 type compounds their 15 u03b2 epimers and racemates described following example 10 is transformed to the corresponding 16 or 16 16 di fluoro pgb 2 type compound or 15 u03b2 epimer or racemic mixture 16 fluoro pge 1 formula viii c n h 2n is ch 2 3 g is 3 m iii is equ49 and r 1 and r 2 are hydrogen and 16 fluoro 13 14 dihydro pge 1 formula xviii c n h 2n is ch 2 3 g is 3 m iii is equ50 a mixture of the formula xxxvi bis tetrahydropyranyl ether of 16 fluoro pge 2 example 9 220 mg 5 rhodium on alumina catalyst 40 mg and 16 ml of ethyl acetate is stirred under one atmosphere of hydrogen at about 0 u00b0 c until substantially all of the starting material has been used as shown by tlc the mixture is filtered to remove catalysts and the filtrate is concentrated the residue is dissolved in 1 ml of tetrahydrofuran and 6 ml of 66 acetic acid and the mixture is warmed to 50 u00b0 c for 2 5 hr the mixture is concentrated under reduced pressure and the residue is chromatographed over silica gel eluting with the upper layer of a mixture of ethyl.