1-methylimidazolidine-2,4,5-trione

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

Procedure: 6.6 g of methylurea was added to 200 ml of anhydrous tetrahydrofuran and the suspension was stirred in an ice-water bath. 12.5 g of oxalyl chloride was added dropwise to the suspension, and the stirring was continued for 30 minutes in an ice-water bath. 200 ml of ethyl acetate and 70 ml of water were added to the reaction mixture and the organic layer was obtained by extraction. The water layer was further extracted with 130 ml of ethyl acetate. The resulting organic layer was dried over anhydrous sodium sulfate and evaporated to dryness, and the crude residue was recrystallized from ethyl acetate-hexane to give 10.0 g of 1-methylimidazolidinetrione in the form of colorless needle crystals. The resulting compound was stirred in 1N ammonia water for a hour at room temperature. The solution was evaporated to dryness and the residue was recrystallized from water-ethanol to give 7.7 g of 5-methyloxaluric acid ammonium salt (compound 1) in the form of colorless prism crystals. the organic layer was obtained by extraction The water layer was further extracted with 130 ml of ethyl acetate The resulting organic layer was dried over anhydrous sodium sulfate evaporated to dryness the crude residue was recrystallized from ethyl acetate-hexane

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

Procedure: 6.6 g of methylurea was added to 200 ml of anhydrous tetrahydrofuran and the suspension was stirred in an ice-water bath. 12.5 g of oxalyl chloride was added dropwise to the suspension, and the stirring was continued for 30 minutes in an ice-water bath. 200 ml of ethyl acetate and 70 ml of water were added to the reaction mixture and the organic layer was obtained by extraction. The water layer was further extracted with 130 ml of ethyl acetate. The resulting organic layer was dried over anhydrous sodium sulfate and evaporated to dryness, and the crude residue was recrystallized from ethyl acetate-hexane to give 10.0 g of 1-methylimidazolidinetrione in the form of colorless needle crystals. The resulting compound was stirred in 1N ammonia water for a hour at room temperature. The solution was evaporated to dryness and the residue was recrystallized from water-ethanol to give 7.7 g of 5-methyloxaluric acid ammonium salt (compound 1) in the form of colorless prism crystals. the organic layer was obtained by extraction The water layer was further extracted with 130 ml of ethyl acetate The resulting organic layer was dried over anhydrous sodium sulfate evaporated to dryness the crude residue was recrystallized from ethyl acetate-hexane

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

Procedure: 2.7 g of potassium hydroxide was dissolved in 150 ml of ethanol. 5.1 g of 1-methylparabanic acid and 10 ml of ethyl bromoacetate were added thereto and the solution was heated under reflux for 6 hours. After cooling, the insoluble substance was filtered off and ethanol was distilled away. The residue was dissolved in ethyl acetate, washed with 5% sodium carbonate and brine, dried over anhydrous sodium sulfate, and passes through silica gel column. Ethyl acetate was distilled away and the residue was recrystallized from hexane to give 3.1 g of ethyl 1-methyl-2,4,5-trioxoimidazolidine-3-acetate (Compound 1). the solution was heated under reflux for 6 hours After cooling the insoluble substance was filtered off ethanol was distilled away The residue was dissolved in ethyl acetate washed with 5% sodium carbonate and brine dried over anhydrous sodium sulfate Ethyl acetate was distilled away the residue was recrystallized from hexane

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

Procedure: 6.6 g of methylurea was added to 200 ml of anhydrous tetrahydrofuran and the suspension was stirred in an ice-water bath. 12.5 g of oxalyl chloride was added dropwise to the suspension, and the stirring was continued for 30 minutes in an ice-water bath. 200 ml of ethyl acetate and 70 ml of water were added to the reaction mixture and the organic layer was obtained by extraction. The water layer was further extracted with 130 ml of ethyl acetate. The resulting organic layer was dried over anhydrous sodium sulfate and evaporated to dryness, and the crude residue was recrystallized from ethyl acetate-hexane to give 10.0 g of 1-methylimidazolidinetrione in the form of colorless needle crystals. The resulting compound was stirred in 1N ammonia water for a hour at room temperature. The solution was evaporated to dryness and the residue was recrystallized from water-ethanol to give 7.7 g of 5-methyloxaluric acid ammonium salt (compound 1) in the form of colorless prism crystals. the organic layer was obtained by extraction The water layer was further extracted with 130 ml of ethyl acetate The resulting organic layer was dried over anhydrous sodium sulfate evaporated to dryness the crude residue was recrystallized from ethyl acetate-hexane

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

Procedure: To a solution of 1-methyl-imidazolidine-2,4,5-trione (Example 1.3, Part A) (800 mg, 6.25 mmol), imidazole (467 mg, 6.87 mmol), N,N-dimethylaminopyridine (cat.) and triethylamine (1.82 mL, 13.1 mmol) in chloroform (13 mL) was added chlorotrimethylsilane (1.67 mL, 13.1 mmol) dropwise at room temperature under a nitrogen atmosphere, and the reaction mixture was stirred for 2 h. Benzylamine (0.75 mL, 6.87 mmol) was added and the reaction mixture was stirred for a further 22.5 h. The reaction mixture was diluted with chloroform and water and the chloroform extracts were dried and evaporated. The crude product was purified by column chromatography (PS with gradient elution to DCM:EtOAc 3:1) to give the product as a colourless solid (838 mg, 62%), mp 152-154° C. δH (300 MHz, CD3CN) 7.95 (v br s, 1H, NH), 7.41-7.27 (m, 5H, PhH), 4.64 (s, 2H, CH2), 2.95 (s, 3H, CH3). Mass spectrum (ESI) m/z 218 (M+H). the reaction mixture was stirred for a further 22.5 h the chloroform extracts were dried evaporated The crude product was purified by column chromatography (PS with gradient elution to DCM:EtOAc 3:1)

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

Procedure: To an ice-cold solution of 1-methylurea (200 mg, 2.70 mmol) in dry tetrahydrofuran (6 mL) was added oxalyl chloride (0.26 mL, 2.97 mmol) dropwise, under a nitrogen atmosphere. The reaction mixture was stirred at 0-5° for 2 h and then allowed to warm to room temperature for 1 h before being diluted with water. The product was extracted with ethyl acetate, and the extracts were washed with water, dried and evaporated to give the product as an off-white solid (326 mg, 94%), mp 146-149° C. (lit. 145-148° C.). The product was extracted with ethyl acetate the extracts were washed with water dried evaporated

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

Procedure: To a solution of 1-methyl-imidazolidine-2,4,5-trione (Example 1.3, Part A) (800 mg, 6.25 mmol), imidazole (467 mg, 6.87 mmol), N,N-dimethylaminopyridine (cat.) and triethylamine (1.82 mL, 13.1 mmol) in chloroform (13 mL) was added chlorotrimethylsilane (1.67 mL, 13.1 mmol) dropwise at room temperature under a nitrogen atmosphere, and the reaction mixture was stirred for 2 h. Benzylamine (0.75 mL, 6.87 mmol) was added and the reaction mixture was stirred for a further 22.5 h. The reaction mixture was diluted with chloroform and water and the chloroform extracts were dried and evaporated. The crude product was purified by column chromatography (PS with gradient elution to DCM:EtOAc 3:1) to give the product as a colourless solid (838 mg, 62%), mp 152-154° C. δH (300 MHz, CD3CN) 7.95 (v br s, 1H, NH), 7.41-7.27 (m, 5H, PhH), 4.64 (s, 2H, CH2), 2.95 (s, 3M, CH3). Mass spectrum (ESI) m/z 218 (M+H). the reaction mixture was stirred for a further 22.5 h the chloroform extracts were dried evaporated The crude product was purified by column chromatography (PS with gradient elution to DCM:EtOAc 3:1)

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

Procedure: To an ice-cold solution of 1-methylurea (200 mg, 2.70 mmol) in dry tetrahydrofuran (6 mL) was added oxalyl chloride (0.26 mL, 2.97 mmol) dropwise, under a nitrogen atmosphere. The reaction mixture was stirred at 0-5° for 2 h and then allowed to warm to room temperature for 1 h before being diluted with water. The product was extracted with ethyl acetate, and the extracts were washed with water, dried and evaporated to give the product as an off-white solid (326 mg, 94%), mp 146-149° C. (lit. 145-148° C.). The product was extracted with ethyl acetate the extracts were washed with water dried evaporated

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

Procedure: 2.7 g of potassium hydroxide was dissolved in 150 ml of ethanol. 5.1 g of 1-methylparabanic acid and 10 ml of ethyl bromoacetate were added thereto and the solution was heated under reflux for 6 hours. After cooling, the insoluble substance was filtered off and ethanol was distilled away. The residue was dissolved in ethyl acetate, washed with 5% sodium carbonate and brine, dried over anhydrous sodium sulfate, and passes through silica gel column. Ethyl acetate was distilled away and the residue was recrystallized from hexane to give 3.1 g of ethyl 1-methyl-2,4,5-trioxoimidazolidine-3-acetate (Compound 1). the solution was heated under reflux for 6 hours After cooling the insoluble substance was filtered off ethanol was distilled away The residue was dissolved in ethyl acetate washed with 5% sodium carbonate and brine dried over anhydrous sodium sulfate Ethyl acetate was distilled away the residue was recrystallized from hexane

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

Procedure: 6.6 g of methylurea was added to 200 ml of anhydrous tetrahydrofuran and the suspension was stirred in an ice-water bath. 12.5 g of oxalyl chloride was added dropwise to the suspension, and the stirring was continued for 30 minutes in an ice-water bath. 200 ml of ethyl acetate and 70 ml of water were added to the reaction mixture and the organic layer was obtained by extraction. The water layer was further extracted with 130 ml of ethyl acetate. The resulting organic layer was dried over anhydrous sodium sulfate and evaporated to dryness, and the crude residue was recrystallized from ethyl acetate-hexane to give 10.0 g of 1-methylimidazolidinetrione in the form of colorless needle crystals. The resulting compound was stirred in 1N ammonia water for a hour at room temperature. The solution was evaporated to dryness and the residue was recrystallized from water-ethanol to give 7.7 g of 5-methyloxaluric acid ammonium salt (compound 1) in the form of colorless prism crystals. the organic layer was obtained by extraction The water layer was further extracted with 130 ml of ethyl acetate The resulting organic layer was dried over anhydrous sodium sulfate evaporated to dryness the crude residue was recrystallized from ethyl acetate-hexane