17-Dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG) is a chemical compound which is a semi-synthetic derivative of the antibiotic geldanamycin. It is being studied for the possibility of treating cancer. 17-Dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG) is a chemical compound which is a semi-synthetic derivative of the antibiotic geldanamycin. It is being studied for the possibility of treating cancer.