Ethyl 5-oxo-4,5-dihydropyrazolo[1,5-a]pyrimidine-3-carboxylate

Preparation B; Ethyl 5-chloropyrazolor 1 , 5-alpyrimidine-3-carboxylate; Step A: Preparation of ethyl 5-hvdroxypyrazolo[l, 5-a1pyrimidine-3- carboxylate.; Ethyl 3-amino-lH-pyrazole-4-carboxylate (25.0 g, 161 mmol) and (E)-ethyl 3- ethoxyacrylate (35.8 ml, 242 mmol) were mixed in DMF (537 mL). Cesium carbonate (78.7 g, 242 mmol) was added and the mixture heated to 110 To a mixture of ethyl 3-amino-1H-pyrazole-4-carboxylate (29) (30.0 g, 193 mmol) and ethyl 3-ethoxy-2-propenoate (cis- and trans-mixture, 41.9 mL, 290 mmol) in DMF(387 mL) was added cesium carbonate (113 g, 348 mmol). Themixture was stirred at 100°C for 2 h, diluted with water andthen acidified to pH ca. 5 with AcOH. The resulting solid wasfiltered by filtration, washed with water and dried to afford 30(36.4 g, 176 mmol, 91percent) as a beige solid. 1H-NMR (300 MHz, DMSO-d6) δ: 1.28 (3H, t, J=7.1 Hz), 4.28 (2H, q, J=7.1 Hz), 6.15 (1H, d, J=7.9 Hz), 8.13 (1H, s), 8.57 (1H, d, J=7.9 Hz), 11.73 (1H, br s).To a reactor was charged K3PO4 (4104 g granular, 19.3 moles), ethyl 3-amino-lH-pyrazole-4-carboxylate (2000 g, 12.9 moles), and DMF (18.8 kg) and the mixture was agitated. After 20 min, (£)-ethyl 3- ethoxyacrylate, (2230 g, 15.5 moles) was added and the mixture was heated to 110-115 °C internal temperature (IT). After the reaction was judged to be complete based on consumption of starting material , heating was ceased. The mixture was allowed to stir and cool overnight. Aqueous hydrochloric acid (3 M, 13 L) was added over ~ 2 h. DI water (6 L) was added and the mixture was allowed to stir overnight. The mixture was filtered through polypropylene filter cloth (PPFC) and the residue was washed with water (3 x 5 vol, 3 x 10 L). The solid was placed in trays and oven dried under vacuum at 55 °C for 3 days and then 45 °C for 4 days to constant weight of (2553 g 95.6percent).A) The 3-amino -1H-pyrazole-4-carboxylic acid ethyl ester (15.0g) and 3-ethoxy-2-acrylic acid ethyl ester (21.0 ml) for N, N- dimethyl formamide (322 ml) is added in the solution cesium carbonate (56.7g). The reaction mixtures in 100 °C stirring overnight, add water, and adding acetic acid in order to adjust the pH to about 4. The collection of the solid by filtering, and by water cleaning and generates a title compound (17.1g).

Molecular Weight:207.19
XLogP3:-0.1
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:3
Exact Mass:207.06439116
Monoisotopic Mass:207.06439116
Topological Polar Surface Area:73.2
Heavy Atom Count:15
Complexity:316
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes