ethyl 5-tert-butylsulfanyl-2,2-dimethyl-4-oxopentanoate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: N-(4-Bromo-benzyl)-N-(4-methoxy-phenyl)-hydrazine hydrochloride (1.0 eq) was added to a reaction flask containing toluene (10.0-fold, V/W of starting material). To this reaction mixture was added acetic acid (5.0-fold, V/W of starting material), followed by 5-tert-butylsulfanyl-2,2-dimethyl-4-oxo-pentanoic acid ethyl ester (1.05 eq) and NaOAc (2.3 eq). The reaction mixture was agitated at room temperature for about 4 days after which cold water (15.0-fold, V/W of starting material) was added to the reaction and stirred for about 30 minutes. The organic layer was collected and the aqueous layer washed with toluene to recover additional product. The organic portions were collected and washed with water and saturated brine solution. The organic layer was subsequently dried over Na2SO4 and concentrated under reduced pressure. A slurry of collected compound was made with methanol (5.0-fold, V/W of starting material) at 0-5° C. for about 4 hours. The solid was collected and washed with cold methanol. Any remaining solvent was removed by drying under reduced pressure. was added to the reaction The organic layer was collected the aqueous layer washed with toluene to recover additional product The organic portions were collected washed with water and saturated brine solution The organic layer was subsequently dried over Na2SO4 concentrated under reduced pressure A slurry of collected compound was made with methanol (5.0-fold, V/W of starting material) at 0-5° C. for about 4 hours The solid was collected washed with cold methanol Any remaining solvent was removed by drying under reduced pressure

Conditions: temp:-2.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a reaction flask containing THF (5.0-fold, V/W of starting material) was added 5-bromo-2,2-dimethyl-4-oxo-pentanoic acid ethyl ester (1.0 eq) under N2. The mixture was cooled to a temperature of −5-0° C., and a solution of 2-methyl-2-propanethiol (1.2 eq) and triethylamine (1.25 eq) was added while maintaining the temperature below 0° C. The reaction was stirred at room temperature for 25 hours, and then hexane (3.0-fold, V/W of starting material) was slowly added. After agitating for 30 minutes, the solid material was removed by filtration and washed with 50% EtOAc/hexane solution. The filtrate was concentrated under reduced pressure to give the desired product, which was taken on to the next step without further purification. while maintaining the temperature below 0° C After agitating for 30 minutes the solid material was removed by filtration washed with 50% EtOAc/hexane solution The filtrate was concentrated under reduced pressure

Conditions: temp:-2.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a reaction flask containing THF (5.0-fold, V/W of starting material) was added 5-bromo-2,2-dimethyl-4-oxo-pentanoic acid ethyl ester (1.0 eq) under N2. The mixture was cooled to a temperature of −5-0° C., and a solution of 2-methyl-2-propanethiol (1.2 eq) and triethylamine (1.25 eq) was added while maintaining the temperature below 0° C. The reaction was stirred at room temperature for 25 hours, and then hexane (3.0-fold, V/W of starting material) was slowly added. After agitating for 30 minutes, the solid material was removed by filtration and washed with 50% EtOAc/hexane solution. The filtrate was concentrated under reduced pressure to give the desired product, which was taken on to the next step without further purification. while maintaining the temperature below 0° C After agitating for 30 minutes the solid material was removed by filtration washed with 50% EtOAc/hexane solution The filtrate was concentrated under reduced pressure

Conditions: temp:-2.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a reaction flask containing THF (5.0-fold, V/W of starting material) was added 5-bromo-2,2-dimethyl-4-oxo-pentanoic acid ethyl ester (1.0 eq) under N2. The mixture was cooled to a temperature of −5-0° C., and a solution of 2-methyl-2-propanethiol (1.2 eq) and triethylamine (1.25 eq) was added while maintaining the temperature below 0° C. The reaction was stirred at room temperature for 25 hours, and then hexane (3.0-fold, V/W of starting material) was slowly added. After agitating for 30 minutes, the solid material was removed by filtration and washed with 50% EtOAc/hexane solution. The filtrate was concentrated under reduced pressure to give the desired product, which was taken on to the next step without further purification. while maintaining the temperature below 0° C After agitating for 30 minutes the solid material was removed by filtration washed with 50% EtOAc/hexane solution The filtrate was concentrated under reduced pressure

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: [4-(Pyridin-2-ylmethoxy)-phenyl]-hydrazine dihydrochloride (75 g), 5-tert-butylsulfanyl-2,2-dimethyl-4-oxo-pentanoic acid ethyl ester (64 g), NaOAc (40 g) in toluene (800 mL) and HOAc (400 mL) was stirred at room temperature for 3 days. In one aspect, 5-tert-butylsulfanyl-2,2-dimethyl-4-oxo-pentanoic acid ethyl ester was prepared according to the procedures described in U.S. Pat. No. 5,288,743 issued Feb. 22, 1994. In another aspect, 5-tert-butylsulfanyl-2,2-dimethyl-4-oxo-pentanoic acid ethyl ester was prepared as outlined herein. The mixture was poured into water and made basic with solid Na2CO3. The mixture was extracted with EtOAc (×3), then washed with water (×2), brine, dried (MgSO4), filtered and concentrated to give a dark red-black oil. Column chromatography of the mother liquor (silica gel packed in hexanes; eluting with hexane then hexane-EtOAc 9:1 rising to 4:1) afforded 68 g of the title compound, as a yellow solid. The mixture was extracted with EtOAc (×3) washed with water (×2), brine dried (MgSO4) filtered concentrated to give a dark red-black oil eluting with hexane

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1-(4-Chlorobenzyl)-1-(4-methoxyphenyl)hydrazine hydrochloride (50 g; 190 mmol), prepared as in step 1, was dissolved in 400 mL toluene and 220 mL acetic acid. Sodium acetate (17.1 g; 210 mmol) was added followed by the addition of ethyl 5-t-butylthio-2,2-dimethyl-4-oxopentanoate (49 g; 188 mmol), prepared as in step 2. The reaction was stirred in the dark at room temperature for 4 days. The mixture was poured into water and extracted with ethyl acetate. The combined extracts were washed with water. Solid sodium bicarbonate was added to the organic extracts and the mixture was filtered. The filtrate was washed with water and brine, dried over magnesium sulfate and the solvent was removed under reduced pressure. The residue was taken up in hot ethyl acetate and filtered. The solvent was removed and the product was recrystallized from pentane to give ethyl 3-[1-(4-chlorobenzyl)-3-(1,1-dimethylethylthio)-5-methoxyindol-2-yl]-2,2-dimethylpropionate as a fluffy white solid. extracted with ethyl acetate The combined extracts were washed with water Solid sodium bicarbonate was added to the organic extracts the mixture was filtered The filtrate was washed with water and brine dried over magnesium sulfate the solvent was removed under reduced pressure filtered The solvent was removed the product was recrystallized from pentane

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: N-(4-Bromo-benzyl)-N-(4-methoxy-phenyl)-hydrazine hydrochloride (1.0 eq) was added to a reaction flask containing toluene (10.0-fold, V/W of starting material) under nitrogen. Acetic acid (5.0-fold, V/W of starting material) was added, followed by 5-tert-butylsulfanyl-2,2-dimethyl-4-oxo-pentanoic acid ethyl ester (1.05 eq) and sodium acetate (2.3 eq), and the reaction mixture was stirred at room temperature for 4 days. Cold water (15.0-fold, V/W of starting material) was then added to the reaction, and the mixture was agitated for 30 minutes. The organic layer was separated, and the aqueous layer was extracted with toluene (2.0-fold, V/W of starting material) to recover additional product. The combined organic layers were washed with water and brine, dried over sodium sulfate, and concentrated under reduced pressure. A slurry of the crude material was made in methanol (5.0-fold, V/W of starting material), and the mixture was cooled to 0-5° C. for 4 hours. The solid was collected by filtration and washed with cold methanol, and the isolated material was dried under reduced pressure at 28-30° C. the mixture was agitated for 30 minutes The organic layer was separated the aqueous layer was extracted with toluene (2.0-fold, V/W of starting material) to recover additional product The combined organic layers were washed with water and brine dried over sodium sulfate concentrated under reduced pressure the mixture was cooled to 0-5° C. for 4 hours The solid was collected by filtration washed with cold methanol the isolated material was dried under reduced pressure at 28-30° C.

Conditions: temp:-2.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a reaction flask containing tetrahydrofuran (5.0-fold, V/W of starting material) was added 5-bromo-2,2-dimethyl-4-oxo-pentanoic acid ethyl ester (1.0 eq) under nitrogen. The mixture was cooled to a temperature of −5-0° C., and a solution of 2-methyl-2-propanethiol (1.2 eq) and triethylamine (1.25 eq) was added while maintaining the temperature below 0° C. The reaction was stirred at room temperature for 25 hours, and then hexane (3.0-fold, V/W of starting material) was slowly added. After agitating for 30 minutes, the solid material was removed by filtration and washed with 50% ethyl acetate/hexane solution. The filtrate was concentrated under reduced pressure to give the desired product, which was taken on to the next step without further purification. while maintaining the temperature below 0° C After agitating for 30 minutes the solid material was removed by filtration washed with 50% ethyl acetate/hexane solution The filtrate was concentrated under reduced pressure