A method of making a biphenol dianhydride composition includes heating a first solution including a biphenol tetraacid of the formula (I) wherein Ra, Rb, p and q are as defined herein; at least one of sodium ions, potassium ions, calcium ions, zinc ions, aluminum ions, iron ions, phosphate ions, sulfate ions, chloride ions, nitrate ions, and nitrite ions; and a non-halogenated solvent. The first solution is heated under conditions effective to provide a second solution including the corresponding biphenol dianhydride, the at least one of sodium ions, potassium ions, calcium ions, zinc ions, aluminum ions, iron ions, phosphate ions, sulfate ions, chloride ions, nitrate ions, and nitrite ions, and the non-halogenated solvent.

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A method of making a biphenol dianhydride composition includes heating a first solution including a biphenol tetraacid of the formula (I) wherein Ra, Rb, p and q are as defined herein; at least one of sodium ions, potassium ions, calcium ions, zinc ions, aluminum ions, iron ions, phosphate ions, sulfate ions, chloride ions, nitrate ions, and nitrite ions; and a non-halogenated solvent. The first solution is heated under conditions effective to provide a second solution including the corresponding biphenol dianhydride, the at least one of sodium ions, potassium ions, calcium ions, zinc ions, aluminum ions, iron ions, phosphate ions, sulfate ions, chloride ions, nitrate ions, and nitrite ions, and the non-halogenated solvent.

##STR00001##

The present invention is directed to the preparation of phthalic anhydride compounds and the intermediate phthalide compounds. In particular, the invention is directed to an improved bio-based route from furanic compounds to phthalic anhydride compounds by reacting furfuryl alcohol (i.e. 2-hydroxymethylfuran) or an analogue thereof having a nucleophilic atom on the 2-methyl, with a dienophile comprising an α,β-unsaturated carbonyl comprising an α′-leaving group. The inventions further involved preparation of phthalic anhydride compounds, phthalic acid compounds and reduction products of the intermediate phthalide compounds.

The present invention is directed to the preparation of phthalic anhydride compounds and the intermediate phthalide compounds. In particular, the invention is directed to an improved bio-based route from furanic compounds to phthalic anhydride compounds by reacting furfuryl alcohol (i.e. 2-hydroxymethylfuran) or an analogue thereof having a nucleophilic atom on the 2-methyl, with a dienophile comprising an α,β-unsaturated carbonyl comprising an α′-leaving group. The inventions further involved preparation of phthalic anhydride compounds, phthalic acid compounds and reduction products of the intermediate phthalide compounds.

A method for producing an aromatic dianhydride includes reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent in a first extractor for a first time period, at a first extraction temperature and subsequent to the first time period, extracting the aqueous reaction mixture with an organic solvent in a second extractor for a second time period, at a second extraction temperature. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.

A method for producing an aromatic dianhydride includes re-acting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent and converting to the corresponding aromatic dianhydride. The extracting is carried out in an extraction column including a high specific surface area metal packing material and having an interface between the aqueous reaction mixture and the organic solvent that is at a level that is 14 to 85% of the height of the extraction column.

A method for producing an aromatic dianhydride includes re-acting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent and converting to the corresponding aromatic dianhydride. The extracting is carried out in an extraction column including a high specific surface area metal packing material and having an interface between the aqueous reaction mixture and the organic solvent that is at a level that is 14 to 85% of the height of the extraction column.

The present invention can synthesize lobaric acid and four analogues thereof, which are five phenolic lichen metabolites isolated from an extract of the Antarctic lichen Stereocaulon alpinum and selectively inhibit PTP1B, by a simple, economic and efficient chemical synthesis method.

Gracilin A congeners and methods for their use as immunosuppressive and neuroprotective agents.

Gracilin A congeners and methods for their use as immunosuppressive and neuroprotective agents.