The invention relates to a method for producing a biomass-resource-derived polyurethane, which comprises: reacting a dicarboxylic acid and an aliphatic diol to produce a polyester polyol; and reacting the polyester polyol and a polyisocyanate compound, wherein the dicarboxylic acid contains at least one component derived from biomass resources, a content of an organic acid in the dicarboxylic acid is more than 0 ppm and not more than 1,000 ppm relative to the dicarboxylic acid, and a pKa value of the organic acid at 25? C. is not more than 3.7.

The invention relates to a method for producing a biomass-resource-derived polyurethane, which comprises: reacting a dicarboxylic acid and an aliphatic diol to produce a polyester polyol; and reacting the polyester polyol and a polyisocyanate compound, wherein the dicarboxylic acid contains at least one component derived from biomass resources, a content of an organic acid in the dicarboxylic acid is more than 0 ppm and not more than 1,000 ppm relative to the dicarboxylic acid, and a pKa value of the organic acid at 25? C. is not more than 3.7.

Provided herein are tartaric acid analogs represented by the following structural formula: or a pharmaceutically acceptable salt thereof, wherein values for the variables (e.g., A, R) are as described herein. Compounds of structural formula I and pharmaceutically acceptable salts thereof are believed to be useful in overcoming tumor resistance and promoting an immune response. Accordingly, also provided herein are various methods involving compounds of structural formula I, e.g., methods of treating a cancer in a subject in need thereof.

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Provided herein are tartaric acid analogs represented by the following structural formula: or a pharmaceutically acceptable salt thereof, wherein values for the variables (e.g., A, R) are as described herein. Compounds of structural formula I and pharmaceutically acceptable salts thereof are believed to be useful in overcoming tumor resistance and promoting an immune response. Accordingly, also provided herein are various methods involving compounds of structural formula I, e.g., methods of treating a cancer in a subject in need thereof.

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