A salicyl fumarate derivative, and its general structural formula (A) is:

##STR00001##

Where the structural formula (A), R.sub.1 is one of H.sup.+, Na.sup.+, K.sup.+ or NH4.sup.+. R.sub.2 is one of fumaric acid ester products. It has the general structural formula of the combination of salicylic acid and fumaric acid through esterification reaction. This category of compounds possesses good effects in treatment of neurodegenerative diseases.

Disclosed embodiments relate to improved methods for the synthesis of activated fumarate intermediates and their use in chemical synthesis. Disclosed embodiments describe the synthesis of activated fumarate esters including those derived from activating groups including: 4-nitrophenyl, diphenylphophoryl azide, pivaloyl chloride, chlorosulfonyl isocyanate, p-nitrophenol, MEF, trifluoroacetyl and chlorine, for example, ethyl fumaroyl chloride and the subsequent use of the activated ester in situ. Further embodiments describe the improved synthesis of substituted aminoalkyl-diketopiperazines from unisolated and unpurified intermediates allowing for improved yields and reactor throughput.

Disclosed embodiments relate to improved methods for the synthesis of activated fumarate intermediates and their use in chemical synthesis. Disclosed embodiments describe the synthesis of activated fumarate esters including those derived from activating groups including: 4-nitrophenyl, diphenylphophoryl azide, pivaloyl chloride, chlorosulfonyl isocyanate, p-nitrophenol, MEF, trifluoroacetyl and chlorine, for example, ethyl fumaroyl chloride and the subsequent use of the activated ester in situ. Further embodiments describe the improved synthesis of substituted aminoalkyl-diketopiperazines from unisolated and unpurified intermediates allowing for improved yields and reactor throughput.

Disclosed embodiments relate to improved methods for the synthesis of activated fumarate intermediates and their use in chemical synthesis. Disclosed embodiments describe the synthesis of activated fumarate esters including those derived from activating groups including: 4-nitrophenyl, diphenylphophoryl azide, pivaloyl chloride, chlorosulfonyl isocyanate, p-nitrophenol, MEF, trifluoroacetyl and chlorine, for example, ethyl fumaroyl chloride and the subsequent use of the activated ester in situ. Further embodiments describe the improved synthesis of substituted aminoalkyl-diketopiperazines from unisolated and unpurified intermediates allowing for improved yields and reactor throughput.

Disclosed embodiments relate to improved methods for the synthesis of activated fumarate intermediates and their use in chemical synthesis. Disclosed embodiments describe the synthesis of activated fumarate esters including those derived from activating groups including: 4-nitrophenyl, diphenylphophoryl azide, pivaloyl chloride, chlorosulfonyl isocyanate, p-nitrophenol, MEF, trifluoroacetyl and chlorine, for example, ethyl fumaroyl chloride and the subsequent use of the activated ester in situ. Further embodiments describe the improved synthesis of substituted aminoalkyl-diketopiperazines from unisolated and unpurified intermediates allowing for improved yields and reactor throughput.

The present invention relates to chain extenders, processes for their preparation and their use in the preparation of biocompatible biodegradable polyurethanes and polyurethane ureas for biomedical applications such as stents, scaffolds for tissue engineering. The chain extenders comprise a compound of formula (I) ##STR00001##

The present invention relates to chain extenders, processes for their preparation and their use in the preparation of biocompatible biodegradable polyurethanes and polyurethane ureas for biomedical applications such as stents, scaffolds for tissue engineering. The chain extenders comprise a compound of formula (I) ##STR00001##

A salicyl fumarate derivative having the general structural formula (A): ##STR00001##
In the structural formula (A), R.sub.1 is one of H.sup.+, Na.sup.+, K.sup.+or NH.sup.4+. R.sub.2 is one of fumaric acid ester products. The derivative has the general structural formula of the combination of salicylic acid and fumaric acid through an esterification reaction. This category of compounds possesses good effects in treatment of neurodegenerative diseases.

A salicyl fumarate derivative having the general structural formula (A): ##STR00001##
In the structural formula (A), R.sub.1 is one of H.sup.+, Na.sup.+, K.sup.+or NH.sup.4+. R.sub.2 is one of fumaric acid ester products. The derivative has the general structural formula of the combination of salicylic acid and fumaric acid through an esterification reaction. This category of compounds possesses good effects in treatment of neurodegenerative diseases.

The invention discloses a method for preparing maleate by selective catalytic oxidation of lignin. The method uses a heteropolyacid functionalized ionic liquid as a catalyst, and an aqueous alcohol solution as a reaction medium to achieve high-efficiency selective catalytic conversion and ring opening oxidation of biomass lignin at a reaction temperature of 110-160 C. and an oxygen pressure of 0.5-1.0 MPa for 1-6 h. The selectivity of maleate is higher than 47.83%. The yield and selectivity of a single chemical derived from the depolymerization of lignin in the present invention are much higher than the prior art, and the ionic liquid catalyst exhibits outstanding advantages such as availability of recovery and recycling through simple temperature adjustment; the reaction conditions of the present invention are mild, and the process is green and safe, easy to operate, and available for batch and continuous production. The invention provides a new green way for preparing bulk chemicals like maleate from reproducible raw materials such as lignin.