2-Amino-4-hydroxy-6-phenylpyrimidine

Intermediate 1A : Preparation of 4-chloro-6-phenylpyrimidin-2-amine; A suspension of guanidine carbonate (3.60 g, 20 mmol) in ethanol (120 mL) and toluene (20 mL) was refluxed under nitrogen for 1 h, during which time about 50 mL of solvent was removed by distillation. After the mixture was cooled to 45 °C, ethyl 3-oxo-3- phenylpropanoate (7.68 g, 40 mmol) was added and the solution was heated at reflux overnight. The desired product precipitated as a white solid during the reaction. Water (50 mL) was added to the reaction and the mixture was refluxed for an additional 30 min. After cooling to rt, the mixture was neutralized with 1N HC1 and placed in the refrigerator for 6 h. The solid was filtered, washed with water followed by ether and dried at 60 °C under vacuum to give the product as white solid (6.45 g, 86percent). MS ES: 188 (M+H) +, calcd 188; RT = 0.91 min; TLC (CH2C12/2M NH3 in MeOH 95/5) Rf = 0.10. A mixture of the above product (6.0 g, 32 mmol) and POC13 (100 mL) was heated at reflux for 1 h. The majority of the POC13 was removed in vacuo and the residue was diluted with EtOAc and poured over an ice/saturated NaHC03 solution. The aqueous layer was extracted with EtOAc and the combined organic layers were washed with brine, dried (Na2SO4), and concentrated. The crude organic concentrate was re-crystallized from EtOAc/ether to give the product 1A as an off-white powder (2. 8 g, 43percent). MS ES: 206 (M+H) +, calcd 206; RT = 2.49 min; TLC (CH2C12/2M NH3 in MeOH 95/5) Rf = 0.72. (Reference 1: H. L. Skulnick, S. D. Weed, E. E. Edison, H. E. Renis, W. Wierenga, and D. A. Stringfellow, J ; Med. Cllem. 1985, 28, 1854-1869).General procedure: To a suspension of guanidine carbonate (1.5-5 eq) in ethanol (2 mL/mmol) was added γ-aryl-β-ketoester (1.43-26.6 mmol), and the reaction mixture heated at 80 °C for 15-64 h. Followingreaction completion by TLC, the mixture was cooled to ambient temperature, filtered and thesolid triturated with water (5-20 mL) and acetone (5-20 mL) to give the title compound.A mixture of methyl 3-oxo-3-phenylpropanoate (2.0 g) , guanidine (2.02 g) and sodium methanolate (1.12 g) in methanol (50 mL) was stirred at 65°C overnight under a nitrogen atmosphere. The reaction mixture was evaporated under reduced pressure. The residue was purified by washed with methanol: ethyl acetate (1:10) as eluent to give the desired compound (800 mg) as a white solid. LC-MS m/z [M+H]Intermediate 1A : Preparation of 4-chloro-6-phenylpyrimidin-2-amine; A suspension of guanidine carbonate (3.60 g, 20 mmol) in ethanol (120 mL) and toluene (20 mL) was refluxed under nitrogen for 1 h, during which time about 50 mL of solvent was removed by distillation. After the mixture was cooled to 45 °C, ethyl 3-oxo-3- phenylpropanoate (7.68 g, 40 mmol) was added and the solution was heated at reflux overnight. The desired product precipitated as a white solid during the reaction. Water (50 mL) was added to the reaction and the mixture was refluxed for an additional 30 min. After cooling to rt, the mixture was neutralized with 1N HC1 and placed in the refrigerator for 6 h. The solid was filtered, washed with water followed by ether and dried at 60 °C under vacuum to give the product as white solid (6.45 g, 86percent). MS ES: 188 (M+H) +, calcd 188; RT = 0.91 min; TLC (CH2C12/2M NH3 in MeOH 95/5) Rf = 0.10. A mixture of the above product (6.0 g, 32 mmol) and POC13 (100 mL) was heated at reflux for 1 h. The majority of the POC13 was removed in vacuo and the residue was diluted with EtOAc and poured over an ice/saturated NaHC03 solution. The aqueous layer was extracted with EtOAc and the combined organic layers were washed with brine, dried (Na2SO4), and concentrated. The crude organic concentrate was re-crystallized from EtOAc/ether to give the product 1A as an off-white powder (2. 8 g, 43percent). MS ES: 206 (M+H) +, calcd 206; RT = 2.49 min; TLC (CH2C12/2M NH3 in MeOH 95/5) Rf = 0.72. (Reference 1: H. L. Skulnick, S. D. Weed, E. E. Edison, H. E. Renis, W. Wierenga, and D. A. Stringfellow, J ; Med. Cllem. 1985, 28, 1854-1869).General procedure: To a suspension of guanidine carbonate (1.5-5 eq) in ethanol (2 mL/mmol) was added γ-aryl-β-ketoester (1.43-26.6 mmol), and the reaction mixture heated at 80 °C for 15-64 h. Followingreaction completion by TLC, the mixture was cooled to ambient temperature, filtered and thesolid triturated with water (5-20 mL) and acetone (5-20 mL) to give the title compound.A mixture of methyl 3-oxo-3-phenylpropanoate (2.0 g) , guanidine (2.02 g) and sodium methanolate (1.12 g) in methanol (50 mL) was stirred at 65°C overnight under a nitrogen atmosphere. The reaction mixture was evaporated under reduced pressure. The residue was purified by washed with methanol: ethyl acetate (1:10) as eluent to give the desired compound (800 mg) as a white solid. LC-MS m/z [M+H]General procedure: To a suspension of guanidine carbonate (1.5-5 eq) in ethanol (2 mL/mmol) was added gamma-aryl-beta-ketoester (1.43-26.6 mmol), and the reaction mixture heated at 80 C for 15-64 h. Followingreaction completion by TLC, the mixture was cooled to ambient temperature, filtered and thesolid triturated with water (5-20 mL) and acetone (5-20 mL) to give the title compound.