反应详情

A mechanically stirred solution of tert-butyl 2-isopropylidene-1-(4-methylbenzyl)hydrazinecarboxylate (crude product from Step 2) in THF (950 mL) and HCl (3N aq., 360 mL) was warmed to reflux. After being stirred for 3 h, the yellow solution was cooled to rt and concentrated to a white solid. The crude material was dried under high vacuum overnight, was suspended in Et2O, and was filtered to provide the title compound as a crystalline white solid (87.8 g, 87% for 2 steps): 1H NMR (300 MHz, d6-DMSO) δ 2.27 (s, 3H), 4.00 (s, 2H), 7.17 (d, 2H), 7.29 (d, 2H).

1. concentrationconcentrated to a white solid
2. dry with materialThe crude material was dried under high vacuum overnight
3. filtrationwas filtered