Phosphorus oxychloride → 2-[2-(Pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazol-3-yl]-oxazolo[4,5-b]pyridine

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Reaction Steps

In a similar fashion to Example 8, react 2-amino-3-hydroxypyridine (Fluka; 144 mg, 1.3 mmol) and phosphorous oxychloride (4.4 mL) with 2-(pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-carboxylic acid (Preparation 3; 250 mg, 1.1 mmol) to provide the title compound (74 mg, 22%) as a tan solid. Mp 182-184° C. MS ESI+ m/e 304 (M+1). 1H NMR (CDCl3) δ 8.75 (m, 1H), 8.52 (m, 1H), 8.12 (m, 1H), 7.84 (m, 1H), 7.69 (m, 1H), 7.32 (m, 1H), 7.15 (m, 1H), 4.31 (m, 2H), 7.37 (m, 2H), 2.75 (m, 2H). HPLC: 98.3%, Rt=13.95 min. TLC (SiO2): Rf0.4 (1:3 [80:18:2 chloroform/methanol/concentrated aqueous ammonium hydroxide]/dichloromethane).

Provenance & Evidence