3,4-DIHYDROXY-THIOPHENE-2,5-DICARBOXYLIC ACID DIETHYL ESTER

Pale yellow to white solid

General procedure: Example B1 2) Synthesis of diethyl 3, 4-dihydroxythiophene-2, 5-dicarboxylate; [0080] In a 2 L two-necked flask equipped with a reflux condenser 175 g (2.57 mol) of sodium ethoxide was dissolved in 1200 mL anhydrous ethanol The reaction was cooled to 0 C and a solution of 106 g (0.514 mol) diethylthioglycolate and 188 g (1.28 mol) diethyl oxalate in ethanol was added dropwise. Upon completion of the addition, the cooling bath was removed and the reaction heated to reflux overnight. The reaction was then cooled to room temperature and filtered The resulting yellow solid was washed with ethanol and allowed to dry. The solid was split into two portions and each was added to a large Erlenmeyer flask with water to make a suspension upon stirring. Acidification with HCl provided a white solid. The solid was filtered and allowed to dry under vacuum to give 80g (60percent yield) of product as a white powder. Further mateπal can be isolated by cooling the mother liquor and subsequent filtration. Structure and puπty were confirmed by Η/In a 1-liter four-necked flask, 82.8 g (0.24 mol) of 20percent sodium ethoxide (Wako Pure Chemical Industries, reagent grade 1) was charged under a nitrogen atmosphere and cooled to 5 ° C. To this, a solution obtained by adding 20.6 g (0.10 mol) of diethyl thioglycolate obtained in a) and 17.2 g (0.12 mol) of diethyl oxalate (manufactured by Wako Pure Chemical Industries, special grade) to ethanol 18.8 g was added dropwise over 1 hour. Further, the mixture was heated under reflux for 1.0 hour. After the completion of the reaction, the reaction solution was concentrated at 60 ° C/16 to 20 mmHg, and 515.2 g of water was added, cooled to 5 ° C, and 38.1 g (0.37 mol) of 35percent hydrochloric acid was added dropwise at 5 to 10 ° C to obtain a white precipitate. The obtained precipitate was filtered, dispersed in water, washed and filtered, and then dried at 60 ° C/1 mmHg for 4 hours to obtain 23.8 g of a white powder. In the same manner, 44.9 g of a white powder was obtained. These powders were single peaks by gas chromatography analysis and when 1 H-NMR and 13 C-NMR were measured, it was confirmed that they were 3, 4-dihydroxy-2, 5-dicarboxylic acid thiophene diethyl ester.

Molecular Weight:260.27
XLogP3:3.1
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:7
Rotatable Bond Count:6
Exact Mass:260.03545927
Monoisotopic Mass:260.03545927
Topological Polar Surface Area:121
Heavy Atom Count:17
Complexity:267
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes