| abstract |
Process for the production of prostaglandin intermediatesnof formula I wherein R is n-n-butyl-, phenoxy, optionally substitutednin the 3-position with chloro or trifluoromethylnthe group A represents hydrogen, Bndenotes hydroxyl or together A + B togethernis an OCH 2 CH 2 O group by transesterificationna lactone ester of formula II, whereinnR, A and B are as defined above and R * 1nis P-C 6 H 5 C 6 H 4 CO-, by methanolnin the presence of a catalytic amount of potash,nit consists in the mixture of lactonesternof formula II, anhydrous methanolnand the potash is heated to 40 with stirringnto. 60 ° C after 10 to 30 minutes, and thennafter cooling to 15-25 ° C, acidified with acidnhydrochloric or sulfuric, againnneutralized with solid bicarbonatenwith sodium, after cooling to 5 to 10 ° Cnthe insoluble fractions are filtered off and after distillationnmethanol, the solid distillation residue is trituratednat 15 to 25 ° C with an organic solvent,nwhereupon the precipitated solid is isolatednby filtration or decantation and after optionalnrecrystallization yields the product of generalnof formula I.nThe compounds of formula I are importantnintermediates in the production of prostaglandins. |