Difluoromaleic anhydride

Halogenation. Halogens add directly to the double bond of maleic anhydride to give dihalo succinic acids. However, different procedures are used for dihalomaleic anhydride derivatives. Fluorinated substrates offer access to difluoromaleic anhydride [669-78-3] (64). 

Hexafluoro-2,5-dihydrofuran [24849-02-3] is distilled into sulfur trioxide [7446-11-9] at 25°C. Addition of trimethyl borate [121-43-7] initiates a reaction which upon heating and distillation leads to a 53% yield of difluoromaleic anhydride. Dichloromaleic anhydride [1122-17-4] can be prepared with 92% selectivity by oxidation of hexachloro-1,3-butadiene with SO in the presence of iodine-containing molecules (65). Passing vaporized... 

Diflubenzuron, registered for use in aquaculture in Europe, 3 220t Difluorobromine tetrafluoroborate, 4 144t 1,1-Difluoroethane, 13 722 physical properties of, l 778t Difluoromaleic anhydride, 15 492 Difunctional initiators, 14 252-254 23 380, 381 24 706... 

A convenient route to difluoromaleic anhydride is based on the reaction of F-2,5-dihydrofuran with S03 [183], Oxodefluorination proceeds at elevated temperature and is catalyzed by trimethyl borate. F-2,5-Dihydrothiophene undergoes a similar conversion when excess of S03 is employed, the primary thioanhydride 96 is oxidized to give 97 in high yield ... 

As determined with Stark effect measurements, difluoromaleic anhydride (3,4-difluorofuran-2,5-dione) possesses a dipole moment of 1.867(3) D <1999PCA1758>. 

H. Burger, S. Sommer, /. Chem. Soc. Chem. Commun. 1991, 456-458. In this communication a new method for preparing 96 by gas-phase pyrolysis of perfluoro-l,2,3-triazine is described cf. H. Burger, W. Schneider, S. Sommer, W. Thiel, J. Chem. Phys. 1991, 95, 5660-5669 for matrix and high-resolution infrared studies and ab-initio calculations. Photochemically 96 has been prepared from difluoromaleic anhydride (J. C. Brahms, W. P. Dailey, J. Am. Chem. Soc. 1989, 111, 8940-8941) and difluoropropadienone (J. C. Brahms, W. P. Dailey, J. Am. Chem. Soc. 1990, 112, 4046-4047), inter alia. 

Difluoromaleic anhydride (29) also undergoes ring opening in reactions with nitrogen and oxygen nucleophiles, giving monoamides and monoesters. On the... 

Krespan, C.G. Abbreviated route to difluoromaleic anhydride. J. Fluorine Chem. 1990, 48, 339-343. 

MA-styrene copolymerization, 274 MA-vinyl chloride copolymerization, 274 Chain transfer reactions, MA copolymerization, 282, 308, 329, 331, 390, 396, 407 Charge-transfer complexes AIBN-MA pair, 298 detection methods, 208-210 in Diels-Alder reaction, 140 difluoromaleic anhydride with styrene, 394 difluoromaleic anhydride with vinyl ethers, 394 ene reaction intermediate, 168 equilibrium constants, 332, 390-402, 409, 411, 415-417, 454... 

No products arising from ring transformations occurred upon photolysis or pyrolysis of perfluoro-(2,4,S,6-tetraisopropylpyrimidine) (256). Hydrolysis (aq. H2SO4 at 150 °C) of tetrafluoropyridazine (270) yields initially 3,4,5-trifluoro-l -pyridazine-6-one (271) and then difluoromaleic hydrazide (272) that of perfluoro-(4,5-di-isopropyIpyridazine) (273) yields a mixture of pyridazone (271) and hydrazide (272), and then bis(heptafluorO isopropyl)maleic anhydride (274) at 210 °C (Scheme 55). ... 

---