Furfural diacetate

Checked by James Cason, William G. Dauben, W. B. Fearing, and B. P. Summerer. 

In a 300-ml. Claisen flask, whose side neck is elongated by a 10-cm. indented section, 102 g. (1 mole) of acetic anhydride and 0.1 ml. (Note 1) of concentrated sulfuric acid are mixed by hand swirling. The mixture is cooled to 10° by swirling in an ice bath, then there is added, during about 10 minutes, 96 g. (1 mole) of recently distilled furfural (Note 2). The temperature is maintained at 10-20°. After addition is complete and the contents of the flask have been well mixed by swirling, the cooling bath is removed and the reaction allowed to warm up spontaneously. A maximum temperature of about 35° is usually reached in about 5 minutes. After the temperature has dropped to that of the room (20 30 minutes), 0.4 g. (Note 1) of anhydrous sodium 

In order to freeze the equilibrium during distillation, it is imperative that the sulfuric acid catalyst be previously neutralized by sodium acetate hence it is important that the small quantities of sulfuric acid and sodium acetate be measured carefully. 

The furfural used by the checkers was collected at 158-163°. In several runs made with technical furfural, which had been stored several years and was black and opaque, a satisfactory product was obtained but yields were 45-53%. 

This fore-run turns black on standing, but if stored no more than a few days it may be assumed to be an equimolar mixture of furfural and acetic anhydride and may be used as starting material for subsequent runs. If no additional runs are to be made, the yield may be increased by 5-10% by redistilling the fore-run. 

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Alkylfurans, halofurans, alkoxyfurans, furfuryl ester and ethers, and furfural diacetate [613-75-2] behave similarly. Furans containing electron withdrawing constituents, for example, furfural, 2-furoic acid, and nitrofurans, fail as dienes even with very strong dienophiles. 

Furfural diacetate has been prepared from furfural and acetic anhydride in the presence of various catalysts.2-4 The present method is adapted to recovery and re-use of unreacted starting materials. 

Improved procedures for the isolation of the 1,4-adducts obtained from the reaction of nitronium acetate and furfural diacetate or methyl 2-furoate were reported.366... 

The reaction of nitric acid and furfural in acetic anhydride produces 5-nitro-furfural diacetate, an important intermediate in the production of chemotherapeutic agents, such as nitrofurazone and nitrofurantoin. 

C11H11IO5, Gibberellic acid intermediate, 37B, 165 Cl iHi 20i, 4,7-Dimethoxy-5-methylphthalide, 46B, 311 CliHi2O6, 3-Carbomethoxy-5-anisyl-1,2,4-trioxacyclopentane, 35B, 212 CliHi3NO9, trans-2-Acetoxy-5-nitro-2,5-dihydro-2-furfural diacetate, 46B, 311... 

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