The present invention relates to a cost-effective and efficient method for preparing treprostinil with high purity, and an intermediate therefor.

This present invention relates to novel Lubiprostone crystals and methods for preparing the same. The preparation methods provided by the invention can effectively reduce or eliminate impurity in the obtained Lubiprostone crystals.

The subject of the invention is a process for the preparation of Latanoprostene bunod of formula (I) with a purity higher than 95% where chromatography is used applying normal phase gravity silica gel column chromatography where the used silica gel is irregular silica gel or spherical silica gel an as eluent and eluent mixture consisting of an apolar and a polar solvent is used and if desired, contamination of the purified compound of formula I arising from the solvents are removed by silica gel filtration chromatography.

The subject of the invention is a process for the preparation of Latanoprostene bunod of formula (I) with a purity higher than 95% where chromatography is used applying normal phase gravity silica gel column chromatography where the used silica gel is irregular silica gel or spherical silica gel an as eluent and eluent mixture consisting of an apolar and a polar solvent is used and if desired, contamination of the purified compound of formula I arising from the solvents are removed by silica gel filtration chromatography.

The subject of the invention is a novel process for the preparation of Carboprost tromethamine salt where alkylation the enone of the general formula (II) is carried out in the presence of a chiral auxiliary in aprotic solvent with a Grignard reagent. The methyl ester epimers of formula (VII) are separated by gravity silicagel chromatography and the salt formation is carried out by using solid tromethamine base.

##STR00001##

The subject of the invention is a novel process for the preparation of Carboprost tromethamine salt where alkylation the enone of the general formula (II) is carried out in the presence of a chiral auxiliary in aprotic solvent with a Grignard reagent. The methyl ester epimers of formula (VII) are separated by gravity silicagel chromatography and the salt formation is carried out by using solid tromethamine base.

##STR00001##

Novel processes for preparing cyclopenta[b]naphthalenol derivatives of Formula 1 ##STR00001##
which are useful for the synthesis of corresponding benzindene prostaglandins are provided. The present invention also relates to novel intermediates prepared from the processes.

Novel processes for the preparation of a compound of Formula I-2 substantially free of the 5,6-trans isomer:

##STR00001##

wherein

##STR00002##

R.sub.2, R.sub.3 and R.sub.4 are as defined in the specification are provided. Novel intermediates for the preparations of isomer free Prostaglandins and derivatives thereof are also provided.

Novel processes for the preparation of a compound of Formula I-2 substantially free of the 5,6-trans isomer:

##STR00001##

wherein

##STR00002##

R.sub.2, R.sub.3 and R.sub.4 are as defined in the specification are provided. Novel intermediates for the preparations of isomer free Prostaglandins and derivatives thereof are also provided.

The present invention relates to 15-nitrooxyderivatives of latanoprost and 15-nitrooxyderivatives of latanoprost free acid, their use for the treatment of glaucoma and ocular hypertension and formulation containing 15-nitrooxyderivatives of latanoprost and 15-nitrooxyderivatives of latanoprost free acid.