Abstract: Compounds of the formula (I): wherein R1, R2, R4 and R13 are as defined or a pharmaceutically or veterinarily acceptable salt or polymorph thereof, or a pharmaceutically or veterinarily acceptable solvate or pro-drug thereof: are potent and selective inhibitors of type 5 cyclic guanosine 3?,5?-monophosphate phosphodiesterase (cGMP PDE5) and have utility in the treatment of, inter alia, male erectile dysfunction (MED) and female sexual dysfunction (FSD).

Abstract: A process is provided for the preparation of compounds of formula (I) herein comprising reacting a compound of formula (II), (III), (IV) or (V) in the presence of ?OR3 and a hydroxide trapping agent or in the case of compounds of formula (IV) reacting in the presence of an auxiliary base and a hydroxide trapping agent ( i.e. ?OR3 is substituted by the auxiliary base), wherein X is a leaving group and R1 to R4 are as defined.

Abstract: There is disclosed a two-stage enzymatically catalyzed reaction for the selective preparation of the (R)-endo-isomer of norbornenol from a mixture containing all four stereo- and regioisomers of norbornenol, as well as the synthesis of the intermediate product comprising the enantiomerically enriched mono-ester of (R)-endo-norbornenol and a diacid, and of the enantiomerically enriched saturated alcohol (R)-endo-norborneol. There is also disclosed a method for the production of (R)-endo-norborne-2-ol, by chemical reduction of either the enantiomerically enriched monoester and subsequent hydrolysis, or by hydrolysis of the enantiomerically enriched monoester and then chemical reduction.