diethyl 2,2-dibromopropanedioate

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

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

Procedure: One equivalent of 3,4-dihydroxybenzaldehyde, 1.1 equivalents of diethyl dibromomalonate and powdered potassium carbonate is stirred in acetonitrile at room temperature for 18 hours. The reaction mixture is filtered, evaporated in vacuo, and distilled to give diethyl 5-formyl-1,3-benzodioxole-2,2-dicarboxylate. The reaction mixture is filtered evaporated in vacuo distilled

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

Procedure: One equivalent of 3,4-dihydroxybenzaldehyde, 1.1 equivalents of diethyl dibromomalonate and powdered potassium carbonate is stirred in acetonitrile at room temperature for 18 hours. The reaction mixture is filtered, evaporated in vacuo and distilled to give diethyl 5-formyl-1,3-benzodioxole-2,2-dicarboxylate. 1H NMR(CDCl3): δ 9.9(s,1H,CHO); 7.5(m,2H, aromatic H) ; 7.1(d, 1H,aromatic H); 4.45(q,4H,CH2); 1.8(t,6H,CH3). The reaction mixture is filtered evaporated in vacuo distilled

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

Procedure: A mixture of 0.8 g of the above oxazolidinone, 0.74 g of diethyl dibromomalonate, 1.2 g of anhydrous potassium carbonate and 20 ml of acetone are stirred overnight with the addition of a few drops of diethyl dibromomalonate. The mixture is filtered, washed with acetone and the combined filtrate and wash are evaporated to a yellow oil. The oil is purified by flash chromatography, eluting with 5 percent acetone in toluene. The pure fractions are combined and evaporated, giving 766 mg of (R*,S*)-(±)-5-(2-(5-(3-chlorophenyl)-2-oxo-3-oxazolidinyl)propyl)-1,3-benzodioxole-2,2-dicarboxylic acid, diethyl ester as a colorless oil. The mixture is filtered washed with acetone the combined filtrate and wash are evaporated to a yellow oil The oil is purified by flash chromatography eluting with 5 percent acetone in toluene evaporated

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

Procedure: More specifically, the chiral synthesis may be carried out by performing the synthetic reaction sequence outlined in Scheme III. L-DOPA 19 is treated with di-t-butyl-dicarbonate in dimethylformamide, giving (S)-N-(1-(1,1-dimethylethoxy)carbonyl)-3-hydroxy-L-tyrosine 20 which is reacted with methyl iodide and anhydrous potassium carbonate in acetone, giving (S)-N-(1,1-dimethylethoxy)carbonyl)-3,4-dimethoxy-L-phenylalanine methyl ester 21 which is reduced with lithium borohydride giving (S)-1,1-dimethylethyl-(2-(3,4-dimethoxyphenyl)-1-(hydroxymethyl)ethyl) carbonate 22, which is reacted with methanesulfonyl chloride and triethylamine in methylene chloride, giving (S)-1,1-dimethylethyl-(2-(3,4-dimethoxyphenyl)-1(((methylsulfonyl) oxy)methyl)ethyl)carbamate 23. Compound 23 is treated with trifluoroacetic acid and then is reduced using 10% Pd/C and hydrogen giving (R)-3,4-dimethoxy- -methylbenzeneethanamine 24. The compound 24 is treated with 3-chlorostyrene oxide 25 and N-(trimethylsilyl) acetamide giving a mixture of (R,S)- and (S,S)-3-chloro-(((2-(3,4-dimethoxyphenyl)-1-methylethyl)amino)methyl) benzenemethanol 26. Reaction of 26 with carbonyl diimidazole and triethylamine in tetrahydrofuran, followed by chromatographic separation of the diastereomers gives cyclized derivative 27, which is reacted with boron tribromide in dichloromethane, giving (R,R)-5-(3-chlorophenyl)-3-(2-(3,4-dihydroxyphenyl)-1-methylethyl)-2-oxazolidinone 28. Compound 28 is then reacted with diethyl dibromomalonate and anhydrous potassium carbonate in acetone, giving (R,R)-5-(2-(5-(3-chlorophenyl)-2-oxo-3-oxazolidinyl)propyl)-1,3-benzodioxole-2,2-dicarboxylic acid, diethyl ester 29. Compound 29 is reacted with 5N sodium hydroxide in ethanol and then isolated by reverse phase chromatography to give (R,R)-1,3-benzodioxole-2,2-dicarboxylic acid, 5-(2-((2-(3-chlorophenyl)-2-hydroxyethyl)amino)propyl)-, disodium salt 15.

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

Procedure: In accordance with the above preferred reaction scheme 2-(3-chlorophenyl)-2-hydroxyethylamine 1, and 3,4-dimethoxyphenylacetone 2 are reacted with sodium cyanoborohydride in methanol, giving 3-chloroalpha-(((2-(3,4-dimethoxyphenyl)-1-methylethyl)amino)methyl) benzenemethanol 3 which is reacted with carbonyl diimidazole and triethylamine in tetrahydrofuran, followed by separation of isomers, giving cyclized derivative 4 which is reacted with boron tribromide in dichloromethane, giving (R*,R*)-(±)-5-(3-chlorophenyl)-3-(2-(3,4-dihydroxy phenyl)-1-methylethyl)2-oxazolidinone 5. Compound 5 is then reacted with diethyl dibromomalonate and anhydrous potassium carbonate in acetone, giving (R*,R*)-(±)-5-(2-(5-(3-chlorophenyl)-2-oxo-3-oxazolidinyl)propyl)-1,3-benzodioxole-2,2-dicarboxylic acid, diethyl ester 6 which is then reacted first with sodium hydroxide in ethanol and then with hydrogen chloride gas in methanol, giving the product (R*,R*)-(±) 5-(2-((2-(3-chlorophenyl)2-hydroxyethyl)-amino)propyl)-1,3-benzodioxole-2,2-dicarboxylic acid, dimethyl ester 7.

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

Procedure: A mixture of 0.90 g of the above catechol derivative, 0.836 g of diethyl dibromomalonate and 1.8 g of powdered anhydrous potassium carbonate in 15 ml of acetone is stirred at room temperature for 18 hours. The reaction mixture is filtered and concentrated in vacuo to give 0.708 g of a mixture of diastereomers as a colorless oil. The reaction mixture is filtered concentrated in vacuo

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

Procedure: A mixture of 0.8 g of the above oxazolidinone, 0 74 g of diethyl dibromomalonate, 1.2 g of anhydrous potassium carbonate and 20 ml of acetone are stirred overnight with the addition of a few drops of diethyl dibromomalonate. The mixture is filtered, washed with acetone and the combined filtrate and wash are evaporated to a yellow oil. The oil is purified by flash chromatography, eluting with 5 percent acetone in toluene. The pure fractions are combined and evaporated, giving 766 mg of (R*,S*)-(+/-)-5-(2-(5-(3-chlorophenyl)-2-oxo-3-oxazolidinyl)propyl)-1,3-benzodioxole-2,2-dicarboxylic acid, diethyl ester as a colorless oil. The mixture is filtered washed with acetone the combined filtrate and wash are evaporated to a yellow oil The oil is purified by flash chromatography eluting with 5 percent acetone in toluene evaporated

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

Procedure: A mixture of 0.8 g of the above oxazolidinone, 0 74 g of diethyl dibromomalonate, 1.2 g of anhydrous potassium carbonate and 20 ml of acetone are stirred overnight with the addition of a few drops of diethyl dibromomalonate. The mixture is filtered, washed with acetone and the combined filtrate and wash are evaporated to a yellow oil. The oil is purified by flash chromatography, eluting with 5 percent acetone in toluene. The pure fractions are combined and evaporated, giving 766 mg of (R*,S*)-(+/-)-5-(2-(5-(3-chlorophenyl)-2-oxo-3-oxazolidinyl)propyl)-1,3-benzodioxole-2,2-dicarboxylic acid, diethyl ester as a colorless oil. The mixture is filtered washed with acetone the combined filtrate and wash are evaporated to a yellow oil The oil is purified by flash chromatography eluting with 5 percent acetone in toluene evaporated

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

Procedure: More specifically, the chiral synthesis may be carried out by performing the synthetic reaction sequence outlined in Scheme III. L-DOPA 19 is treated with di-t-butyl-dicarbonate in dimethylformamide, giving (S)-N-(1-(1,1-dimethylethoxy)carbonyl)-3-hydroxy-L-tyrosine 20 which is reacted with methyl iodide and anhydrous potassium carbonate in acetone, giving (S)-N-(1,1-dimethylethoxy)carbonyl)-3,4-dimethoxy-L-phenylalanine methyl ester 21 which is reduced with lithium borohydride giving (S)-1,1-dimethylethyl-(2-(3,4-dimethoxyphenyl)-1-(hydroxymethyl)ethyl) carbonate 22, which is reacted with methanesulfonyl chloride and triethylamine in methylene chloride, giving (S)-1,1-dimethylethyl-(2-(3,4-dimethoxyphenyl)-1(((methylsulfonyl) oxy)methyl)ethyl)carbamate 23. Compound 23 is treated with trifluoroacetic acid and then is reduced using 10% Pd/C and hydrogen giving (R)-3,4-dimethoxy- -methylbenzeneethanamine 24. The compound 24 is treated with 3-chlorostyrene oxide 25 and N-(trimethylsilyl) acetamide giving a mixture of (R,S)- and (S,S)-3-chloro-(((2-(3,4-dimethoxyphenyl)-1-methylethyl)amino)methyl) benzenemethanol 26. Reaction of 26 with carbonyl diimidazole and triethylamine in tetrahydrofuran, followed by chromatographic separation of the diastereomers gives cyclized derivative 27, which is reacted with boron tribromide in dichloromethane, giving (R,R)-5-(3-chlorophenyl)-3-(2-(3,4-dihydroxyphenyl)-1-methylethyl)-2-oxazolidinone 28. Compound 28 is then reacted with diethyl dibromomalonate and anhydrous potassium carbonate in acetone, giving (R,R)-5-(2-(5-(3-chlorophenyl)-2-oxo-3-oxazolidinyl)propyl)-1,3-benzodioxole-2,2-dicarboxylic acid, diethyl ester 29. Compound 29 is reacted with 5N sodium hydroxide in ethanol and then isolated by reverse phase chromatography to give (R,R)-1,3-benzodioxole-2,2-dicarboxylic acid, 5-(2-((2-(3-chlorophenyl)-2-hydroxyethyl)amino)propyl)-, disodium salt 15.

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

Procedure: In accordance with the above preferred reaction scheme 2-(3-chlorophenyl)-2-hydroxyethylamine 1, and 3,4-dimethoxyphenylacetone 2 are reacted with sodium cyanoborohydride in methanol, giving 3-chloroalpha-(((2-(3,4-dimethoxyphenyl)-1-methylethyl)amino)methyl) benzenemethanol 3 which is reacted with carbonyl diimidazole and triethylamine in tetrahydrofuran, followed by separation of isomers, giving cyclized derivative 4 which is reacted with boron tribromide in dichloromethane, giving (R*,R*)-(+/-)-5-(3-chlorophenyl)-3-(2-(3,4-dihydroxy phenyl)-1-methylethyl)2-oxazolidinone 5. Compound 5 is then reacted with diethyl dibromomalonate and anhydrous potassium carbonate in acetone, giving (R*,R*)-(+/-)-5-(2-(5-(3-chlorophenyl)-2-oxo-3-oxazolidinyl)propyl)-1, 3-benzodioxole-2,2-dicarboxylic acid, diethyl ester 6 which is then reacted first with sodium hydroxide in ethanol and then with hydrogen chloride gas in methanol, giving the product (R*,R*)-(+/-) 5-(2-((2-(3-chlorophenyl) 2-hydroxyethyl)-amino)propyl)-1,3-benzodioxole-2, 2-dicarboxylic acid, dimethyl ester 7.

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

Procedure: In accordance with the above preferred reaction scheme 2-(3-chlorophenyl)-2-hydroxyethylamine 1, and 3,4-dimethoxyphenylacetone 2 are reacted with sodium cyanoborohydride in methanol, giving 3-chloroalpha-(((2-(3,4-dimethoxyphenyl)-1-methylethyl)amino)methyl) benzenemethanol 3 which is reacted with carbonyl diimidazole and triethylamine in tetrahydrofuran, followed by separation of isomers, giving cyclized derivative 4 which is reacted with boron tribromide in dichloromethane, giving (R*,R*)-(+/-)-5-(3-chlorophenyl)-3-(2-(3,4-dihydroxy phenyl)-1-methylethyl)2-oxazolidinone 5. Compound 5 is then reacted with diethyl dibromomalonate and anhydrous potassium carbonate in acetone, giving (R*,R*)-(+/-)-5-(2-(5-(3-chlorophenyl)-2-oxo-3-oxazolidinyl)propyl)-1, 3-benzodioxole-2,2-dicarboxylic acid, diethyl ester 6 which is then reacted first with sodium hydroxide in ethanol and then with hydrogen chloride gas in methanol, giving the product (R*,R*)-(+/-) 5-(2-((2-(3-chlorophenyl) 2-hydroxyethyl)-amino)propyl)-1,3-benzodioxole-2, 2-dicarboxylic acid, dimethyl ester 7.