Abstract: The haptens 4-[[(2, 3-dihydro-2, 2-dimethyl-7-benzofuranyloxy) carbonyl]-amino] butanoic acid (BFNB) and 6-[((2, 3-dihydro-2, 2-dimethyl-7-benzofuranyloxy)- carbonylamino] hexanoic acid (BFNH) were synthesized and then used to develop a rapid ...