Disclosed are 5-amino-phenol derivatives as represented by the general formula A-I which are useful intermediates in the preparation of ATP-binding cassette transporters, wherein G1 is hydrogen, R', C(O)R', C(S)R', S(O)R', S(O)2R', Si(CH3)2R', P(O)(OR')3, P(S)(OR')3, or B(OR')2； G2 is halo, CN, CF3, isopropyl, or phenyl wherein said isopropyl or phenyl is optionally substituted； G3 is an isopropyl or a cycloaliphatic ring, wherein said G3 is optionally substituted； and wherein the remaining substituents are as defined herein. Representative compounds of the formula A-I include 2-tert-butyl-5-amino-4-fluorophenol, 2-tert-butyl-5-amino-4-chlorophenol and 5-amino-2,4-di-tert-butyl-phenol.
