1H-1,2,4-Triazole → 5-[(2,6-difluoro-4-nitrophenyl)-1,2,4-triazol-1-ylmethyl]-3,3-dimethyl-3H-isobenzofuran-1-one

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Reaction Steps

The diarylcarbinol (5-[(2,6-difluoro-4-nitrophenyl)-hydroxymethyl]-3,3-dimethyl-3H-isobenzofuran-1-one ((Formula I) as prepared in Example 1; 171.3 g, 0.49 moles) and 1,2,4 triazole (85.7 g, 1.24 moles) are charged into a 3L, 4-necked round bottom flask equipped with a mechanical stirrer and a nitrogen inlet. This rapidly stirred mixture is cooled in an ice bath and 680 mL of ice cold concentrated H2SO4 is added in one portion. After 20 min the ice bath is removed and the resultant solution is stirred at room temperature for 20 hr. The dark solution is transferred to an addition funnel and added dropwise over 3 hr to 12L of rapidly stirring ice water in a 22L, 4-necked flask, during which time 5-[(2,6-difluoro-4-nitrophenyl)-[1,2,4]triazol-1-yl-methyl]-3,3-dimethyl-3H-isobenzofuran-1-one precipitates as a fine white solid. After standing for 2 h at 0° C., the solid product is isolated by vacuum filtration, washed with H2O (500 mL), and air dried for 2-12 hr. The resultant solid is transferred to a clean 3L, 4-necked flask equipped with a reflux condenser, mechanical stirrer, and J-Kem thermocouple. 1.5 L of MeOH is added, and the mixture is heated to 55 ° C. to give a dear solution. This solution is filtered while hot into a clean 3L 4-necked flask, equipped with an addition funnel, and mechanical stirrer. H2O (175 mL) is then added dropwise to this rapidly stirred hot solution. As the solution cools, white crystals of 5-[(2,6-difluoro-4-nitrophenyl)-[1,2,4 ]triazol-1-yl-methyl ]-3,3-dimethyl-3H-isobenzofuran-1 -one form. After standing at room temperature for about 2 hr to about 12 hr, the crystals are collected by filtration, air dried for 3 hr, and then dried under vacuum to afford 132.2 g (67 %) of 5-[(2,6-difluoro- 4-nitrophenyl)-[1,2,4]triazol-1-yl-methyl]-3,3-dimethyl-3H-isobenzofuran-1-one which is >98% pure by HPLC analysis.

Provenance & Evidence