N'-Hydroxy-4-methylbenzenecarboximidamide → 5-(3-Tert-butyl-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyridin-7-yl)-3-(p-tolyl)-1,2,4-oxadiazole

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Reaction Steps

Add 4-methylbenzamidoxime (1.44 g, 9.3 mmol) to a 1M solution of potassium tert-butoxide (8.6 mL, 8.6 mmol) diluted with tetrahydrofuran (120 mL). Add ethyl 3-t-butyl-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyridine-7-carboxylate (2.0 g, 7.2 mmol) and stir overnight at room temperature. Dissolve the reaction in a 1:1 mixture of half saturated aqueous sodium bicarbonate and ethyl acetate. Separate the phases and extract the aqueous phase with ethyl acetate. Wash the combined organic layers with aqueous saturated sodium chloride, dry over anhydrous sodium sulfate, filter, and concentrate under reduced pressure. Purify the resulting residue by silica gel flash chromatography eluting with 25-100% ethyl acetate:hexane followed by 5% methanol:ethyl acetate. Recrystallize from dichloromethane and hexane to afford the title compound as a white solid (1.19 g). 1H NMR (CDCl3) δ 1.46 (s, 9H), 2.4 (s, 4H), 2.59 (m, 1H), 3.4 (m, 1H), 3.54-3.69 (m, 2H), 4.11 (m, 1H), 4.38 (m, 1H), 7.22-7.33 (m, 2H), 7.9-7.98 (m, 2H).

Provenance & Evidence