The present invention provides a process for preparing a diester compound of the following general formula (1), having a dimethylcyclobutane ring, wherein R.sup.1 and R.sup.2 represent, independently of each other, a monovalent hydrocarbon group having 1 to 10 carbon atoms, the process comprising reacting a dimethylcyclobutanone compound of the following general formula (2), wherein R.sup.1 is as defined above, with a phosphonic ester compound of the following general formula (3), wherein R.sup.2 and R.sup.3 represent, independently of each other, a monovalent hydrocarbon group having 1 to 10 carbon atoms, to produce the diester compound (1), having a dimethylcyclobutane ring. ##STR00001##

The present invention provides a process for preparing a diester compound of the following general formula (1), having a dimethylcyclobutane ring, wherein R.sup.1 and R.sup.2 represent, independently of each other, a monovalent hydrocarbon group having 1 to 10 carbon atoms, the process comprising reacting a dimethylcyclobutanone compound of the following general formula (2), wherein R.sup.1 is as defined above, with a phosphonic ester compound of the following general formula (3), wherein R.sup.2 and R.sup.3 represent, independently of each other, a monovalent hydrocarbon group having 1 to 10 carbon atoms, to produce the diester compound (1), having a dimethylcyclobutane ring. ##STR00001##

The present invention provides a process for preparing a (1,2-dimethyl-3-methylenecyclopentyl)acetate compound of the following general formula (3), wherein R represents a linear or branched alkyl group having 1 to 4 carbon atoms, the process comprising subjecting a haloacetaldehyde alkyl 2,3-dimethyl-2-cyclopentenyl acetal compound of the following general formula (1), wherein R is as defined above, and Y represents a halogen atom, to a dehydrohalogenation reaction in the presence of a base, followed by a rearrangement reaction to obtain a (1,2-dimethyl-2-cyclopentenyl)acetate compound of the following general formula (2), wherein R is as defined above, and subjecting the (1,2-dimethyl-2-cyclopentenyl)acetate compound (2) to an epoxidation reaction, followed by an isomerization reaction and then a methylenation reaction to obtain the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound of the following general formula (3). The present invention also provides a process for preparing (1,2-dimethyl-3-methylenecyclopentyl)acetaldehyde of the following formula (4), the process comprising the aforesaid process for preparing the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound (3), and converting an alkoxycarbonylmethyl group (i.e., —CH.sub.2C(═O)OR) of the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound (3) to a formylmethyl group (i.e., —CH.sub.2CHO) to obtain (1,2-dimethyl-3-methylenecyclopentyl)acetaldehyde (4). ##STR00001##

The present invention provides a process for preparing a (1,2-dimethyl-3-methylenecyclopentyl)acetate compound of the following general formula (3), wherein R represents a linear or branched alkyl group having 1 to 4 carbon atoms, the process comprising subjecting a haloacetaldehyde alkyl 2,3-dimethyl-2-cyclopentenyl acetal compound of the following general formula (1), wherein R is as defined above, and Y represents a halogen atom, to a dehydrohalogenation reaction in the presence of a base, followed by a rearrangement reaction to obtain a (1,2-dimethyl-2-cyclopentenyl)acetate compound of the following general formula (2), wherein R is as defined above, and subjecting the (1,2-dimethyl-2-cyclopentenyl)acetate compound (2) to an epoxidation reaction, followed by an isomerization reaction and then a methylenation reaction to obtain the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound of the following general formula (3). The present invention also provides a process for preparing (1,2-dimethyl-3-methylenecyclopentyl)acetaldehyde of the following formula (4), the process comprising the aforesaid process for preparing the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound (3), and converting an alkoxycarbonylmethyl group (i.e., —CH.sub.2C(═O)OR) of the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound (3) to a formylmethyl group (i.e., —CH.sub.2CHO) to obtain (1,2-dimethyl-3-methylenecyclopentyl)acetaldehyde (4). ##STR00001##

Treprostinil is a synthetic prostacyclin derivative with thrombocyte aggregation inhibitory and vasodilatory activity. Treprostinil can be administered in subcutaneous, intravenous, inhalable, or oral forms. Disclosed is a method for the preparation of treprostinil of formula I and its amorphous form, anhydrate form, monohydrate form, and polyhydrate form salts with bases. In the disclosed method, the chiral center in the 3-hydroxyoctyl substituent is formed at the end of the synthesis, so that the method is robust and well scalable. Also disclosed are treprostinil intermediates and the preparation of the intermediates. ##STR00001##

Treprostinil is a synthetic prostacyclin derivative with thrombocyte aggregation inhibitory and vasodilatory activity. Treprostinil can be administered in subcutaneous, intravenous, inhalable, or oral forms. Disclosed is a method for the preparation of treprostinil of formula I and its amorphous form, anhydrate form, monohydrate form, and polyhydrate form salts with bases. In the disclosed method, the chiral center in the 3-hydroxyoctyl substituent is formed at the end of the synthesis, so that the method is robust and well scalable. Also disclosed are treprostinil intermediates and the preparation of the intermediates. ##STR00001##

Treprostinil is a synthetic prostacyclin derivative with thrombocyte aggregation inhibitory and vasodilatory activity. Treprostinil can be administered in subcutaneous, intravenous, inhalable, or oral forms. Disclosed is a method for the preparation of treprostinil of formula I and its amorphous form, anhydrate form, monohydrate form, and polyhydrate form salts with bases. In the disclosed method, the chiral center in the 3-hydroxyoctyl substituent is formed at the end of the synthesis, so that the method is robust and well scalable. Also disclosed are treprostinil intermediates and the preparation of the intermediates. ##STR00001##

The present invention provides processes for preparing an α-necrodyl compound of the following general formula (3): wherein R.sup.2 represents a monovalent hydrocarbon group having 1 to 9 carbon atoms, the process comprising: subjecting a 3, 5, 5-trimethyl-3-cyclopentene compound of the following general formula (1): wherein R.sup.2 is as defined above, and X represents a leaving group, to a nucleophilic substitution reaction with a methylating agent of the following general formula (2): wherein M represents Li, MgZ.sup.1, ZnZ.sup.1, Cu, CuZ.sup.1, or CuLiZ.sup.1, and Z.sup.1 represents a halogen atom or a methyl group, to form the α-necrodyl compound (3). The present invention further provides processes for preparing γ-necrodyl compounds of the following general formula (4): wherein R.sup.2 represents a monovalent hydrocarbon group having 1 to 9 carbon atoms, the process comprising: subjecting the α-necrodyl compound (3) thus obtained to a positional isomerization reaction at the double bond to form the γ-necrodyl compound (4).

##STR00001##

The present invention provides processes for preparing an α-necrodyl compound of the following general formula (3): wherein R.sup.2 represents a monovalent hydrocarbon group having 1 to 9 carbon atoms, the process comprising: subjecting a 3, 5, 5-trimethyl-3-cyclopentene compound of the following general formula (1): wherein R.sup.2 is as defined above, and X represents a leaving group, to a nucleophilic substitution reaction with a methylating agent of the following general formula (2): wherein M represents Li, MgZ.sup.1, ZnZ.sup.1, Cu, CuZ.sup.1, or CuLiZ.sup.1, and Z.sup.1 represents a halogen atom or a methyl group, to form the α-necrodyl compound (3). The present invention further provides processes for preparing γ-necrodyl compounds of the following general formula (4): wherein R.sup.2 represents a monovalent hydrocarbon group having 1 to 9 carbon atoms, the process comprising: subjecting the α-necrodyl compound (3) thus obtained to a positional isomerization reaction at the double bond to form the γ-necrodyl compound (4).

##STR00001##

A method for producing tricyclo[5.2.1.0.sup.2,6]decane-2-carboxylate according to the present invention is a method for producing tricyclo[5.2.1.0.sup.2,6]decane-2-carboxylate, containing reacting tricyclo[5.2.1.0.sup.2,6]deca-3-ene in a dilute solution containing the tricyclo[5.2.1.0.sup.2,6]deca-3-ene with carbon monoxide in the presence of an acid catalyst, followed by reaction with an alcohol, wherein the dilute solution contains 100 parts by mass or more of a tricyclo[5.2.1.0.sup.2,6]decane isomer mixture based on 100 parts by mass of the tricyclo[5.2.1.0.sup.2,6]deca-3-ene, the tricyclo[5.2.1.0.sup.2,6]decane isomer mixture contains endo-tricyclo[5.2.1.0.sup.2,6]decane (Endo form of TCD) and exo-tricyclo[5.2.1.0.sup.2,6]decane (Exo form of TCD), and a constituent ratio thereof (Endo form of TCD/Exo form of TCD) is greater than 1.0.