Yield:-

Reaction Conditions:

with sulfuric acid;water at 110; for 22 h;

Steps:

15
Reference Example 15 Synthesis of intermediate compound (107) [Show Image] [Show Image] First step A solution of a compound (106) (1.0 g) in concentrated sulfuric acid (5.4 ml) and water (600 μl) was stirred at 110°C for 22 hours, the mixture was poured into ice water, and the precipitated solid was collected by filtration. The solid was washed with water, and naturally dried to afford the compound (107) (1.02 g). ¹H-NMR(DMSO-d₆) δ: 8.08 (1H, m), 8.60 (1H, m).

References:

Shionogi & Co., Ltd. EP2305672, 2011, A1 Location in patent:Page/Page column 79

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