It is a common heterocyclic compound, the benzoxazole compound, 5-Nitro-2,3-dihydro-1,3-benzoxazol-2-one, cas is 3889-13-2 its synthesis route is as follows.
A solution of 28A (0.69 g, 3.83 mmol) in 2-ethoxyethanol (10 mL) was treated with KOH (0.22 g, 3.83 mmol) and stirred at RT for 1 h. The mixture was then heated to reflux and treated with 1-bromo-3-chloropropane (0.75 mL, 7.67 mmol). After refluxing for 4 h, the solution was filtered and concentrated to provide 28B, which was taken on to Step 3 without further purification.
3889-13-2, In the field of chemistry, the synthetic routes of compounds are constantly being developed and updated. I will also mention this compound in other articles.,3889-13-2 ,5-Nitro-2,3-dihydro-1,3-benzoxazol-2-one, other downstream synthetic routes, hurry up and to see
Reference：
Patent; Schering Corporation and Pharmacopeia Drug Discovery, Inc.; US2007/93477; (2007); A1;,
Benzoxazole – Wikipedia
Benzoxazole | C7H5NO – PubChem