2- Furancarboxylic acid

Carbon tetrachloride may be used for the extraction of the 2-furylcarbinol. This requires altering the extraction apparatus to remove the solvent from the bottom of the extraction bottle. Some difficulties are met in working with carbon tetrachloride, due to the liberation of acid which causes the 2-furylcarbinol to change into the water-insoluble form. The yields of both 2-furancarboxylic acid and 2-furylcarbinol are much lower when carbon tetrachloride is used as a solvent. 

If the solution is cooled lower than 16°, sodium hydrogen sulfate (NaHS04-loHoO) begins to separate with the 2-furancarboxylic acid. 

The low yields of 2-furancarboxylic acid are due partly to the formation of tarry by-products and partly to loss through water solubility. The mother liquors contain about 2.5 g. of 2-furancarboxylic acid per 100 cc. This may be recovered by extraction with ether. 

The melting point of the 2-furancarboxylic acid is not very sharp. The distilled acid which titrates roo per cent softens noticeably at 125 and melts completely at 132°. (Gelissen and van Roon, Rec. trav. chim. 43, 361 (1924)). 

Furancarboxylic acid may be prepared by the dry distillation of mucic acid, by the oxidation of furfural with potassium... 

Propenyl)-1,3-dithiane, after lithiation and addition of zinc chloride, reacts with ethyl 2-oxopropanoate to give preferentially the. vvn-adduct37, which is an intermediate in the synthesis of racemic /ra .s-tetrahydro-2,3-dimethyl-5-oxo-2-furancarboxylic acid. It is assumed, that the ethoxycarbonyl group is brought to a pseudoaxial position in the cyclic transition state by the chelating zinc cation. 

C 7H,203 5675-70-7) see Bisantrene (R)-(-i)-tetrahydrofuran-2-carboxylic acid (CjHgOj 87392-05-0) see Faropenem sodium ( )-tetrahydrofuran-2-carboxylic acid (CjHgOg 16874-33-2) see Alfuzosin Faropenem sodium tetrahydro-2-furancarboxylic acid anhydride with ethyl hydrogen carbonate (CgHijO, 167391-50-6) see Alfuzosin... 

The reaction of benzo-2-furancarboxylic acid with thiosemicarbazide under microwave conditions enables the use of an equivalent amount of phosphorus oxychloride and a short reaction time <2003SC2891 >. Moreover, solvent-free conditions are achieved when acidic alumina is used as dehydrating agent under microwave heating in the reaction of alkyl carboxylic acids with thiosemicarbazide <2000SC3031>. 

Although the Heck reactions of heteroaryl halides are now commonplace [76], few examples are found using organohalide substrates possessing a carboxylic acid moiety [77]. However, 4,5-dibromo-2-furancarboxylic acid (86) underwent a Heck reaction with ethyl acrylate to afford diacrylate 87 [78]. 

In a 200-cc. round bottom flask is placed 80 g. (0.71 mole) of crude 2-furancarboxylic acid (Org. Syn. 6, 44) (usually about 95 per cent pure). To the neck of the flask is fitted an upright tube 2.5 cm. in diameter and 15 cm. long, with a side arm of the same diameter leading out about 2 cm. from the top of the tube. This side arm is extended into the bottom of an efficient (25-cm.) soda-lime tower (Note 1) immersed in a water bath held at 40° to prevent condensation of the furan. From the top of the soda-lime tower an outlet tube (0.5 cm. in diameter) is extended to the top of an upright water condenser, to the lower end of which is attached a receiving flask surrounded by ice and salt (Note 2). 

The top of the upright tube in the reaction flask is closed by a cork stopper holding a glass plunger which may be used for pushing back into the flask any sublimed 2-furancarboxylic acid. 

Care should be taken in heating 2-fura.ncarboxylic acid. If the temperature is too low, decomposition takes place too slowly if too high, much 2-furancarboxylic acid sublimes and causes difficulty. In one run a theimomeLer was placed in the melted acid. It read 200-2050 during the evolution of the furan. 

Limpricht,1 in 1873, prepared furan by heating barium 2-furancarboxylate with soda lime. It has since been prepared by the dry distillation of barium 2-furancarboxylate 2 in small amounts by distillation of calcium succinate 3 by the destructive distillation of resinous pine wood 4 by heating succinaldehyde with water at 1800 0 and by heating 2-furancarboxylic acid in a sealed tube.2... 

Furancarboxylic acid (6, 44) is most satisfactorily purified by recrystallizing from carbon tetrachloride. A few cc. of water should be added to coagulate and float the dark impurities. The clear subjacent liquid is separated and deposits colorless crystals of correct melting point. 

Scheme 1. Oxidation products derived from HMF 2,5-furandicarboxaldehyde (FDC), 5-hydroxymethyl-2-furancarboxylic acid (HFCA), 5-formyl-2-furancarboxylic acid (FFCA) and 2,5-furandicarboxylic acid (FDCA).

Figure 4. Oxidation of HMF over different catalysts under standard conditions (60 °C). v 5-hydroxymethylfurfural (HMF), O 2,5-furandicarboxaldehyde (FDC), a 5-hydroxymethyl-2-furancarboxylic acid (HFCA), o 5-formyl-2-furancarboxylic acid (FFCA), + 2,5-furandicar-boxylic acid (FDCA). Catalysts graph a Pt/Al/Df b Pd/C c Ru/C d 3 Pd/Al-N.

Furancarboxylic acid (0) Glucose-1-phosphate (0) Glycerol-l-phosphoric acid (—1) Glycerol-2-phosphoric acid (0)... 

Ethyl furoate (2-Furancarboxylic acid, ethyl ester) COOC2H5... 

RN 3736-81-0 MF CJ4H C12N04 MW 328.15 EINECS 223-108-1 CN 2-furancarboxylic acid 4-[(dichloroacetyl)methylamino]phenyl ester... 

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