A compound of the formula: or a pharmaceutically acceptable salt thereof, wherein: R 1 is hydrogen or optionally substituted C 1-10 -alkyl, C 1-5 -cycloalkyl, or 5-membered heterocycle, which optional substitution is with one or more R 1A; each R 1A is independently amino, ester, amide, thiol, carboxylic acid, cyano, halo, hydroxyl, or optionally substituted C 1-4 -alkoxy, C 1-5 -cycloalkyl, or 5-membered heterocycle, which optional substitution is with one or more R 1B; each R 1B is independently C 1-4 -alkyl, halo, or hydroxyl; n is 0, 1, or 2; each R 2A is independently hydrogen, C 1-4 -alkyl, or acyl; R 3 is independently halo, hydroxyl, or optionally substituted C 1-10 -alkyl or C 1-10 -alkoxy, which optional substitution is with one or more R 3A; each R 3A is independently amino, ester, amide, thiol, carboxylic acid, cyano, halo, hydroxyl, or optionally substituted C 1-4 -alkoxy, C 1-5 -cycloalkyl, or 5-membered heterocycle, which optional substitution is with one or more R 3B; each R 3B is independently C 1-4 -alkyl, amino, cyano, halo, or hydroxyl; R 4 is -R 4A or -OR 4A R 4A is: - C 1-10 -alkyl-N(R 4C) 2; - C 1-10 -alkyl-N(R 4C)C R 4C; - C 1-10 -alkyl-C N(R 4C) 2; - C 1-10 -alkyl-C N(R 4C)-C 0-6 -alkyl-C R 4C; - C 1-10 -alkyl-C N(R 4C)-C 0-6 -alkyl-C N(R 4C) 2; - C 1-10 -alkyl-N(R 4C)C -C 0-6 -alkyl-N(R 4C) 2; or - C 1-10 -alkyl-N(R 4C)C -C 0-6 -alkyl-N(R 4C)C R 4C each R 4C is independently amino, amido, azo, carbonyl, carboxyl, cyano, formyl, guanidino, halo, hydroxyl, imido, imino, isothiocyanate, nitrile, nitro, nitroso, nitroxy, oxo, sulfanyl, sulfinyl, sulfonyl, thial, thiocyanate, thione, thiourea, urea, or X 1, X 1 -L 1 -X 2, or X 1 -L 1 -X 2 -L 2 -X 3, wherein each of X 1, X 2 and X 3 is independently optionally substituted C 1-4 -alkyl, C 1-6 -cycloalkyl, 5- or 6-membered heterocycle, or aryl, which optional substitution is with one or more R 4D, and each of L 1 and L 2 is independently optionally substituted C 1-6 -alkyl or 1-10-membered heteroalkyl, which optional substitution is with one or more of R 4E; each R 4D is independently R 4E or C 1-6 -alkyl optionally substituted with one or more of R 4E; and each R 4E is independently amino, amido, azo, carbonyl, carboxyl, cyano, formyl, guanidino, halo, hydroxyl, imido, imino, isothiocyanate, nitrile, nitro, nitroso, nitroxy, oxo, sulfanyl, sulfinyl, sulfonyl, thial, thiocyanate, thione, or urea. R 1 is hydrogen or optionally substituted C 1-10 -alkyl, C 1-5 -cycloalkyl, or 5-membered heterocycle, which optional substitution is with one or more R 1A; each R 1A is independently amino, ester, amide, thiol, carboxylic acid, cyano, halo, hydroxyl, or optionally substituted C 1-4 -alkoxy, C 1-5 -cycloalkyl, or 5-membered heterocycle, which optional substitution is with one or more R 1B; each R 1B is independently C 1-4 -alkyl, halo, or hydroxyl; n is 0, 1, or 2; each R 2A is independently hydrogen, C 1-4 -alkyl, or acyl; R 3 is independently halo, hydroxyl, or optionally substituted C 1-10 -alkyl or C 1-10 -alkoxy, which optional substitution is with one or more R 3A; each R 3A is independently amino, ester, amide, thiol, carboxylic acid, cyano, halo, hydroxyl, or optionally substituted C 1-4 -alkoxy, C 1-5 -cycloalkyl, or 5-membered heterocycle, which optional substitution is with one or more R 3B; each R 3B is independently C 1-4 -alkyl, amino, cyano, halo, or hydroxyl; R 4 is -R 4A or -OR 4A R 4A is: - C 1-10 -alkyl-N(R 4C) 2; - C 1-10 -alkyl-N(R 4C)C R 4C; - C 1-10 -alkyl-C N(R 4C) 2; - C 1-10 -alkyl-C N(R 4C)-C 0-6 -alkyl-C R 4C; - C 1-10 -alkyl-C N(R 4C)-C 0-6 -alkyl-C N(R 4C) 2; - C 1-10 -alkyl-N(R 4C)C -C 0-6 -alkyl-N(R 4C) 2; or - C 1-10 -alkyl-N(R 4C)C -C 0-6 -alkyl-N(R 4C)C R 4C - C 1-10 -alkyl-N(R 4C) 2; - C 1-10 -alkyl-N(R 4C)C R 4C; - C 1-10 -alkyl-C N(R 4C) 2; - C 1-10 -alkyl-C N(R 4C)-C 0-6 -alkyl-C R 4C; - C 1-10 -alkyl-C N(R 4C)-C 0-6 -alkyl-C N(R 4C) 2; - C 1-10 -alkyl-N(R 4C)C -C 0-6 -alkyl-N(R 4C) 2; or - C 1-10 -alkyl-N(R 4C)C -C 0-6 -alkyl-N(R 4C)C R 4C each R 4C is independently amino, amido, azo, carbonyl, carboxyl, cyano, formyl, guanidino, halo, hydroxyl, imido, imino, isothiocyanate, nitrile, nitro, nitroso, nitroxy, oxo, sulfanyl, sulfinyl, sulfonyl, thial, thiocyanate, thione, thiourea, urea, or X 1, X 1 -L 1 -X 2, or X 1 -L 1 -X 2 -L 2 -X 3, wherein each of X 1, X 2 and X 3 is independently optionally substituted C 1-4 -alkyl, C 1-6 -cycloalkyl, 5- or 6-membered heterocycle, or aryl, which optional substitution is with one or more R 4D, and each of L 1 and L 2 is independently optionally substituted C 1-6 -alkyl or 1-10-membered heteroalkyl, which optional substitution is with one or more of R 4E; each R 4D is independently R 4E or C 1-6 -alkyl optionally substituted with one or more of R 4E; and each R 4E is independently amino, amido, azo, carbonyl, carboxyl, cyano, formyl, guanidino, halo, hydroxyl, imido, imino, isothiocyanate, nitrile, nitro, nitroso, nitroxy, oxo, sulfanyl, sulfinyl, sulfonyl, thial, thiocyanate, thione, or urea.