N-Iodosuccinimide → 7-(2-Chlorophenyl)-8-iodo-2-methyl-3H-pyrazolo[1,5-a][1,3,5]triazin-4-one

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Reaction Steps

To a suspension of 7-(2-chlorophenyl)-2-methyl-3H-pyrazolo[1,5-a]-[1,3,5]triazin-4-one (I-1A-1c; 18.9 g, 72.6 mmol) in methylene chloride (290 ml) cooled in an ice bath was added N-iodosuccinimide (18.0 g, 79.9 mmol). The mixture became homogeneous orange solution within 5 minutes. After stirring for 5 hours, the mixture was washed with 50% saturated aqueous NH4OH (160 ml), 1 M aqueous Na2S2O3 (120 ml), and brine (120 ml). The solution was concentrated, in vacuo, and then concentrated again from MTBE (150 ml). Additional MTBE (75 ml) was added and stirred for 1 hour. The resulting solid precipitate was collected by vacuum filtration in a course sintered glass funnel, washed with MTBE (50 ml) and then dried, in vacuo, to afford product I-1A-1d as a solid (25.5 g, 91%): +APcI MS (M+1) 387.3; 1H NMR (400 MHz, CD3OD) δ 7.54 (d, J=7.1 Hz, 1H), 7.51-7.39 (m, 3H), 2.45 (S, 3H).

Provenance & Evidence