O=C1c2c(O)cccc2C(C(=O)CCCCC(=O)C2c3cccc(O)c3C(=O)c3c(O)cccc32)c2cccc(O)c21
The donor in a hydrogen bond is usually a strongly electronegative atom such as N, O, or F that is covalently bonded to a hydrogen bond. How many hydrogen bond donors does the molecule have?