Compounds, compositions and methods are provided for inhibiting corrosion at a surface in the production, transportation, storage, and separation of fluids such as crude oil and natural gas, the compounds having the formula: wherein: Each R1 is independently —CH2OH and —C(O)OH; R2 is Each R3 is independently hydrogen or R5, or both R3 together form a ring via a linker Each R4 is independently hydrogen or R5; R5 is —CH2SC2H4R1; and n is an integer from 0 to 3.