Ethanol → 4-Aminobenzoic Acid

Participants

Reaction Steps

In 70 ml of dimethyl sulfoxide (DMSO) containing 20 percent of ethanol, 1.94 g (0.02 mole) of polymaleimide was dissolved. The resultant solution, with 2 ml of 37 percent formalin solution added thereto, was thermally refluxed at temperatures of 70° to 75° C. To the substance obtained by the thermal reflux was added a solution obtained by dissolving 2.74 g (0.02 mole) of m-aminobenzoic acid in 10 ml of a DMSO solution containing 20 percent of ethanol. This mixed solution was refluxed for two hours. Then, the reaction solution was cooled, and the cooled reaction solution was added to a mixed solution of water and methanol to precipitate insoluble components. The final precipitate was separated by filtration and dissolved in a DMSO solution. The resultant solution was purified by repeated addition of water and methanol in the manner just mentioned, and finally dried. A 2.46-g portion (0.01 mole) of poly-m-maleimidemethyl aminobenzoic acid thus obtained was dissolved in a mixed solution of water and tetrahydrofuran and cooled with water. Separately, 1 g (0.01 mole) of 2-aminothiazole was dissolved in 20 ml of 6 normal hydrochloric acid and cooled. A solution obtained by dissolving 0.74 g of sodium nitrite in a small amount of water was gradually added, while under ice cooling, to the 2-aminothiazole solution to effect diazotization. The resultant diazotized solution was added to the cooled poly-m-maleimidemethyl aminobenzoic acid solution, with the molar ratio of poly-m-maleimidemethyl aminobenzoic acid to the diazotized compound at 1:1, to effect diazo coupling. The precipitate which consequently occurred was separated by filtration and dissolved in dioxane. The resultant solution was poured in a mixed solution of water and methanol. The precipitate was again purified and dried to afford 3.37 g of PTAMMABC (m.p. 280° C.).

Provenance & Evidence