2,2,6,6-tetramethyloxane-3,5-dione

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2,2,6,6-Tetramethylpyran-3,5-dione (8 g, 0.047 mol) and 4-dimethylaminopyridine (24 g, 0.196 mol) are added to a mixture of chloroform (160 ml) and toluene (40 ml). The reaction mixture is flushed with nitrogen for 15 minutes at ambient temperature. 4-Bromo-2-ethyl-phenyllead triacetate (29.4 g, 0.051 mol) is added in one portion and the reaction mixture is stirred and heated to 80° C. (pre-heated oil bath) under an atmosphere of nitrogen for 1 hour. The reaction mixture is cooled to room temperature, acidified to pH 1 with 2N aqueous hydrochloric acid, filtered through a plug of diatomaceous earth and the two phases are separated. The aqueous phase is extracted with dichloromethane (2×100 ml), the organic phases are combined, washed with water, and dried over anhydrous sodium sulfate. The mixture is filtered, and the filtrate is evaporated under reduced pressure. The residue is purified by column chromatography on silica gel to give 4-(4-bromo-2-ethylphenyl)-2,2,6,6-tetramethylpyran-3,5-dione as a white solid (10 g). The reaction mixture is flushed with nitrogen for 15 minutes at ambient temperature (pre-heated oil bath) under an atmosphere of nitrogen for 1 hour The reaction mixture is cooled to room temperature filtered through a plug of diatomaceous earth the two phases are separated The aqueous phase is extracted with dichloromethane (2×100 ml) washed with water dried over anhydrous sodium sulfate The mixture is filtered the filtrate is evaporated under reduced pressure The residue is purified by column chromatography on silica gel

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 4-Dimethylaminopyridine (3.13 g, 25.7 mmol) and toluene (10 ml) are added to a solution of 2,2,6,6-tetramethylpyran-3,5-dione (0.87 g, 5.13 mmol) in chloroform (40 ml) and the reaction mixture is heated to 80° C. 4-Bromo-2-ethylphenyllead triacetate (3.50 g, 6.16 mmol) is added portionwise over 5 minutes, and once the addition is complete the reaction mixture is stirred at 80° C. for a further 4 hours. The mixture is cooled to room temperature, 2M aqueous hydrochloric acid (40 ml) is added, and the mixture is stirred vigorously for 20 minutes, then filtered through a small plug of diatomaceous earth, washing with dichloromethane (40 ml). The organic phase is separated, and the aqueous phase is extracted with dichloromethane (2×40 ml). The organic solutions are combined, dried over anhydrous magnesium sulfate, filtered and the filtrate is concentrated under reduced pressure. The residue is purified by column chromatography on silica gel to give 4-(4-bromo-2-ethylphenyl)-2,2,6,6-tetramethylpyran-3,5-dione. once the addition The mixture is cooled to room temperature the mixture is stirred vigorously for 20 minutes filtered through a small plug of diatomaceous earth washing with dichloromethane (40 ml) The organic phase is separated the aqueous phase is extracted with dichloromethane (2×40 ml) dried over anhydrous magnesium sulfate filtered the filtrate is concentrated under reduced pressure The residue is purified by column chromatography on silica gel

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

Procedure: To a mixture of 2,2,6,6-tetramethylpyran-3,5-dione (described in U.S. Pat. No. 5,089,046A) (0.296 g, 1.74 mmol) and N,N-dimethylaminopyridine (1.06 g, 8.70 mmol) is added anhydrous chloroform (20 ml), followed by stirring at room temperature until dissolution. To this solution is added anhydrous toluene (5 ml), followed by 4′-chloro-4-methylbiphenyl-3-yllead triacetate (1.12 g, 1.91 mmol) in one portion and the reaction mixture heated at 80° C. for 1-2 hours. The mixture is allowed to cool to room temperature, then diluted with dichloromethane (150 ml) and dilute aqueous hydrochloric acid (30 ml), followed by stirring for 5 minutes and filtration through diatomaceous earth to remove inorganic residues (additional washing with solvents). All organic fractions are combined, dried over anhydrous magnesium sulfate and concentrated in vacuo. The crude product is purified by column chromatography (100% hexane to hexane/ethyl acetate 5:1 ratio) then triturated with hexanes to afford 4-(4′-chloro-4-methylbiphenyl-3-yl)-2,2,6,6-tetramethylpyran-3,5-dione (0.318 g) as a cream powder. the reaction mixture heated at 80° C. for 1-2 hours to cool to room temperature by stirring for 5 minutes filtration through diatomaceous earth to remove inorganic residues (additional washing with solvents) dried over anhydrous magnesium sulfate concentrated in vacuo The crude product is purified by column chromatography (100% hexane to hexane/ethyl acetate 5:1 ratio) then triturated with hexanes

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

Procedure: To a mixture of 2,2,6,6-tetramethylpyran-3,5-dione (3.57 g, 21.00 mmol) and N,N-dimethylaminopyridine (13.50 g, 111.00 mmol) is added anhydrous chloroform (120 ml), followed by stirring at room temperature until dissolution. To this solution is added anhydrous toluene (37 ml), followed by 5-bromo-2-ethylphenyllead triacetate (10.69 g, 24.00 mmol) in one portion and the reaction mixture is heated at 80° C. for 2 hours, then allowed to stand overnight at room temperature. The mixture is diluted with dichloromethane (185 ml) and dilute aqueous hydrochloric acid (185 ml), followed by swirling for 5 minutes and filtration to remove inorganic residues (additional washing with dichloromethane). All organic fractions are combined, washed with brine, dried over anhydrous magnesium sulfate, then concentrated in vacuo to afford a crude oil which is further purified by flash column chromatography (hexane/ethyl acetate 5:1 ratio) to give the product as a yellow solid (4.47 g). Lead residues are removed by dissolving this solid in chloroform (50 ml) and stirring with 3-mercaptopropyl-functionalized silica gel (5.50 g, 1.20 mmol/g loading) overnight. After filtration and concentration 4-(5-bromo-2-ethylphenyl)-2,2,6,6-tetramethylpyran-3,5-dione (4.36 g) is afforded as a cream powder. the reaction mixture is heated at 80° C. for 2 hours by swirling for 5 minutes filtration to remove inorganic residues (additional washing with dichloromethane) washed with brine dried over anhydrous magnesium sulfate concentrated in vacuo to afford a crude oil which is further purified by flash column chromatography (hexane/ethyl acetate 5:1 ratio)

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

Procedure: To a mixture of 2,2,6,6-tetramethylpyran-3,5-dione (3.57 g, 21.00 mmol) and N,N-dimethylaminopyridine (13.50 g, 111.00 mmol) is added anhydrous chloroform (120 ml), followed by stirring at room temperature until dissolution. To this solution is added anhydrous toluene (37 ml), followed by 5-bromo-2-ethylphenyllead triacetate (10.69 g, 24.00 mmol) in one portion and the reaction mixture is heated at 80° C. for 2 hours, then allowed to stand overnight at room temperature. The mixture is diluted with dichloromethane (185 ml) and dilute aqueous hydrochloric acid (185 ml), followed by swirling for 5 minutes and filtration to remove inorganic residues (additional washing with dichloromethane). All organic fractions are combined, washed with brine, dried over anhydrous magnesium sulfate, then concentrated in vacuo to afford a crude oil which is further purified by flash column chromatography (hexane/ethyl acetate 5:1 ratio) to give the product as a yellow solid (4.47 g). Lead residues are removed by dissolving this solid in chloroform (50 ml) and stirring with 3-mercaptopropyl-functionalized silica gel (5.50 g, 1.20 mmol/g loading) overnight. After filtration and concentration 4-(5-bromo-2-ethylphenyl)-2,2,6,6-tetramethylpyran-3,5-dione (4.36 g) is afforded as a cream powder. the reaction mixture is heated at 80° C. for 2 hours by swirling for 5 minutes filtration to remove inorganic residues (additional washing with dichloromethane) washed with brine dried over anhydrous magnesium sulfate concentrated in vacuo to afford a crude oil which is further purified by flash column chromatography (hexane/ethyl acetate 5:1 ratio)

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2,2,6,6-Tetramethylpyran-3,5-dione (8 g, 0.047 mol) and 4-dimethylaminopyridine (24 g, 0.196 mol) are added to a mixture of chloroform (160 ml) and toluene (40 ml). The reaction mixture is flushed with nitrogen for 15 minutes at ambient temperature. 4-Bromo-2-ethyl-phenyllead triacetate (29.4 g, 0.051 mol) is added in one portion and the reaction mixture is stirred and heated to 80° C. (pre-heated oil bath) under an atmosphere of nitrogen for 1 hour. The reaction mixture is cooled to room temperature, acidified to pH 1 with 2N aqueous hydrochloric acid, filtered through a plug of diatomaceous earth and the two phases are separated. The aqueous phase is extracted with dichloromethane (2×100 ml), the organic phases are combined, washed with water, and dried over anhydrous sodium sulfate. The mixture is filtered, and the filtrate is evaporated under reduced pressure. The residue is purified by column chromatography on silica gel to give 4-(4-bromo-2-ethylphenyl)-2,2,6,6-tetramethylpyran-3,5-dione as a white solid (10 g). The reaction mixture is flushed with nitrogen for 15 minutes at ambient temperature (pre-heated oil bath) under an atmosphere of nitrogen for 1 hour The reaction mixture is cooled to room temperature filtered through a plug of diatomaceous earth the two phases are separated The aqueous phase is extracted with dichloromethane (2×100 ml) washed with water dried over anhydrous sodium sulfate The mixture is filtered the filtrate is evaporated under reduced pressure The residue is purified by column chromatography on silica gel

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A microwave vial is charged with 4-chloro-2-(4-chlorophenyl)-5-methylpyrimidine (239 mg, 1 mmol), 2,2,6,6-tetramethyl-pyran-3,5-dione (170 mg, 1 mmol), palladium acetate (12 mg, 0.05 mmol), X-Phos (48 mg, 0.1 mmol) and potassium phosphate (424 mg, 2 mmol). 1,2-dimethoxyethane (3 ml) is added and the reaction heated to 150° C., with stirring, for 30 minutes. Silica gel is added to the crude reaction mixture, the solvent is evaporated under reduced pressure and the residue is purified by flash chromatography on silica gel to give 4-[2-(4-chlorophenyl)-5-methylpyrimidin-4-yl]-2,2,6,6-tetramethylpyran-3,5-dione. Silica gel is added to the crude reaction mixture the solvent is evaporated under reduced pressure the residue is purified by flash chromatography on silica gel

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

Procedure: To a suspension of 2,2,6,6-tetramethylpyran-3,5-dione (741 mg, 4.35 mmol) in chloroform (10 ml) is added phosphorus pentachloride (454 mg, 2.18 mmol), and the reaction is heated to reflux for 5 hours. Silica gel is added to the cooled crude reaction mixture, the solvent is evaporated under reduced pressure and the residue is purified by flash chromatography on silica gel to give 5-chloro-2,2,6,6-tetramethyl-6H-pyran-3-one (349 mg). the reaction is heated to reflux for 5 hours Silica gel is added to the cooled crude reaction mixture the solvent is evaporated under reduced pressure the residue is purified by flash chromatography on silica gel

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

Procedure: To a mixture of 2,2,6,6-tetramethylpyran-3,5-dione (0.75 g, 4.9 mmol) and N,N-dimethylaminopyridine (2.52 g, 20.6 mmol) is added anhydrous chloroform (40 ml), followed by stirring at room temperature until dissolution. To this solution is added anhydrous toluene (12 ml), followed by 4-bromo-4′-chlorobiphenyl-3-yllead triacetate (3.25 g, 5.1 mmol) in one portion and the reaction mixture is heated at 80° C. for 2 hours. The mixture is cooled to room temperature, diluted with chloroform (50 ml) and 1M aqueous hydrochloric acid (50 ml), and the mixture is stirred for 5 minutes. The precipitate is removed by filtration, the two phases separated, and the organic phase is washed with brine, dried over anhydrous magnesium sulfate, filtered and the filtrate is evaporated in vacuo. The residue is purified by flash column chromatography on silica gel, and fractions containing the desired compound are combined and evaporated to give a residue which is further purified by preparative reverse phase HPLC to give 4-(4-bromo-4′-chlorobiphenyl-3-yl)-2,2,6,6-tetramethylpyran-3,5-dione (0.013 g). the reaction mixture is heated at 80° C. for 2 hours The mixture is cooled to room temperature the mixture is stirred for 5 minutes The precipitate is removed by filtration the two phases separated the organic phase is washed with brine dried over anhydrous magnesium sulfate filtered the filtrate is evaporated in vacuo The residue is purified by flash column chromatography on silica gel, and fractions containing the desired compound evaporated to give a residue which is further purified by preparative reverse phase HPLC

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a mixture of 2,2,6,6-tetramethylpyran-3,5-dione (2.78 g, 16.3 mmol) and N,N-dimethylaminopyridine (9.97 g, 81.6 mmol) is added anhydrous chloroform (120 ml). To this solution is added anhydrous toluene (30 ml), followed by 5-bromo-2-chlorophenyllead triacetate (10.32 g, 18 mmol) in one portion and the reaction mixture is heated at 80° C. overnight. The mixture is allowed to cool to room temperature, then diluted with dichloromethane (120 ml) and 2M aqueous hydrochloric acid (250 ml), followed by filtration through diatomaceous earth to remove inorganic residues. The filter cake is washed with dichloromethane, and all organic fractions are combined, washed with 2M hydrochloric acid, water and brine, dried over anhydrous magnesium sulfate then concentrated in vacuo. This material is finally purified by flash column chromatography on silica gel to afford 4-(5-bromo-2-chlorophenyl)-2,2,6,6-tetramethylpyran-3,5-dione (0.44 g) of sufficient purity to use directly in the next step. to cool to room temperature followed by filtration through diatomaceous earth to remove inorganic residues The filter cake is washed with dichloromethane washed with 2M hydrochloric acid, water and brine dried over anhydrous magnesium sulfate then concentrated in vacuo This material is finally purified by flash column chromatography on silica gel