1,3-benzoxazol-2(3H)-one 2(3H)-benzoxazolone 2-benzoxazolinone 59-49-4 BENZOXAZOLINE,2-ONE InChI=1/C7H5NO2/c9-7-8-5-3-1-2-4-6(5)10-7/h1-4H,(H,8,9