Reference of 1101120-37-9, With the rapid development and complex challenges of chemical substances, the synthesis of new drugs is usually one of the most effective ways to increase yield.1101120-37-9, name is Pyrazolo[1,5-a]pyridin-5-amine, molecular formula is C7H7N3, molecular weight is 133.15, as common compound, the synthetic route is as follows.
Decarboxylation of ester 3l (1.29 g, 2.98 mmol), except with carrying out the aqueous extraction from pH 12, gave pyrazolo[1,5-a]pyridin-5-amine (7l) as a pale brown solid (310 mg, 78%). 1H NMR delta (400 MHz, CDCl3) 8.23 (d, J = 7.4 Hz, 1H), 7.79 (d, J = 2.0 Hz, 1H), 6.58 (d, J = 2.4 Hz, 1H), 6.22 (dd, J = 7.4, 2.4 Hz, 1H), 6.13 (d, J = 2.0 Hz, 1H), 3.81 (s, 2H). LC-MS (APCI+) 134 (MH+, 100%). A solution of NaNO2 (27 mg, 0.39 mmol) in water (1 mL) was added dropwise to a solution of 7l (40 mg, 0.30 mmol) and CuCl (74 mg, 0.75 mmol) in concentrated HCl (1 mL) at 0 C over 2 min. After 30 min, the reaction mixture was heated to 80 C for 15 min, and then cooled to room temperature, basified to pH 10 with 1 M NaOH, filtered through a plug of celite and washed with CH2Cl2. The layers of the filtrate were separated and the aqueous layer extracted with CH2Cl2. The combined extracts were dried (Na2SO4) and the solvent removed in vacuo. Chromatography (eluting with hexanes: EtOAc 3:1) gave 5-chloropyrazolo[1,5-a]pyridine (7o) as a white solid (6 mg, 13%). 1H NMR delta (400 MHz, CDCl3) 8.38 (d, J = 7.4 Hz, 1H), 7.95 (d, J = 2.2 Hz, 1H), 7.53 (d, J = 1.8 Hz, 1H), 6.71 (dd, J = 7.4, 2.2 Hz, 1H), 6.47 (d, J = 1.8 Hz, 1H). LC-MS (APCI+) 153 (MH+ with 35Cl, 100%), 155 (MH+ with 37Cl, 30%). Vilsmeier reaction of 7o (6 mg, 0.039 mmol) gave 4o as a white solid (7 mg, 100%).
Statistics shows that 1101120-37-9 is playing an increasingly important role. we look forward to future research findings about Pyrazolo[1,5-a]pyridin-5-amine.
Reference:
Article; Kendall, Jackie D.; O’Connor, Patrick D.; Marshall, Andrew J.; Frederick, Raphael; Marshall, Elaine S.; Lill, Claire L.; Lee, Woo-Jeong; Kolekar, Sharada; Chao, Mindy; Malik, Alisha; Yu, Shuqiao; Chaussade, Claire; Buchanan, Christina; Rewcastle, Gordon W.; Baguley, Bruce C.; Flanagan, Jack U.; Jamieson, Stephen M.F.; Denny, William A.; Shepherd, Peter R.; Bioorganic and Medicinal Chemistry; vol. 20; 1; (2012); p. 69 – 85;,
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