Furoic anhydride

Robinson cyclisation by using 3-acetyl-4-hydroxyquinolines and acid anhydrides in the presence of triethylamine [24], These cyclisations proceeded smoothly with benzoic anhydride but when furoic anhydride or cinnamic anhydride was used (XXXIV, R = Br, Cl, NO2 R = furyl or styryl and R = furoyl or cinnamoyl) were obtained. The phenyl-, furyl-, and styryl-pyranoquinolines gave characteristic colours with sulphuric acid pale yellow for phenyl, orange for furyl and deep red for the styrryl compounds. The ultraviolet absorption spectra were similar to those of corresponding naphtopyrans. 2-Phenylpyrano[3,2-c]quinoline-4-one was also obtained from the dehydrobromination with pyridine of 3-bromo-2-phenyl-2,3-dihydropyrano[3,2-c]quinoline-4-one [24]. Dihydropyrano[3,2-c]quinolines can be dehydrobrominated by iV-bromosuccinimide or selenium dioxide to the corresponding (XXXIV, R = R = H R = Ph) [24]. 

Therapeutics. Compounds containing the furan or tetrahydrofuran ring are biologically active and are present in a number of pharmaceutical products. Eurfurjdamine [617-89-0] is an intermediate in the diuretic, furosemide. Tetrahydrofurfurylamine [4795-29-3] may also have pharmaceutical applications. 5-(E)imethyiaininomethyi)furfuryi alcohol [15433-79-17 is an intermediate in the preparation of ranitidine, which is used for treating ulcers. 2-Acet5dfuran [1192-62-7] prepared from acetic anhydride and furan is an intermediate in the synthesis of cefuroxime, a penicillin derivative. 2-Euroic acid is prepared by the oxidation of furfural. Both furoic acid [88-14-2] and furoyl chloride [527-69-5] are used as pharmaceutical intermediates. 

Formylfuran behaves in a very similar manner to benzaldehyde and undergoes the usual reactions of an aromatic aldehyde, e.g. (i) the Cannizzaro reaction with cone, sodium hydroxide to give furan-2-ylmethanol and the sodium salt of furoic acid, (ii) the Perkin reaction with acetic anhydride and sodium acetate to yield an aldol product that dehydrates to 3-(furan-2-yl)propenoic acid, and (iii) a condensation with potassium cyanide in alcoholic solution to form furoin (under these conditions, benzaldehyde undergoes the benzoin condensation) (Scheme 6.32). 

Acetyl furan [1192-62-7], prepared from acetic anhydride and furan is an intermediate in the synthesis of cefuroxime, a penicillin derivative. 2-Furoic acid is prepared by the oxidation of furfural. Both furoic acid [88-14-2] and furoyl chloride [527-69-5] are used as pharmaceutical intermediates. 

Still another indication of the 1,4-anhydro ring in anhydro-n-xylo-benzimidazole (XX) is its conversion by two hours boiling with acetic anhydride to the same 2-(2-furyl)benzimidazole (XXVI) that is obtained by the direct condensation of o-phenylenediamine (XVIII) with 2-furoic acid (XXVII). 

Furoic acids and derivatives react with maleic anhydride to give unstable adducts,83 e.g.,... 

An analogous methodology can be seen in the proposal to use chloroformamidinium salts as dehydrating agents. A A A /V -Tetramethylchloroformamidinium chloride, used as the condensation agent, is easily available by the reaction of A A A A -tetramethylurea and oxalyl dichloiide. The reaction of carboxylic acids (equation 33) can be achieved at -30 C in the presence of tiiethylamine. Thus, for instance, 2-furoic acid, cinnamic acid and crotonic acid yield e anhydrides in 84%, 83% and 83%, respectively. 

A mixture of 2-t-butylfuran and 2,5-di-t-butylfuran is obtained by the action of t-butyl chloride on furan in the presence of mesitylene nolybdenum tricarbonyl." The intermediate in the nitration of furan-2-aldehyde in acetic anhydride has been identified as compound (26). Treatment of 5-bromo-2-furoic acid with sulphur tetrafluoride in hydrogen fluoride yields the dihydrofuran (27). Bromo-furans are converted into aryl-furans by crosscoupling with aryl Grignard reagents in the presence of nickel(II)-phosphine complexes. 2-Furoic acid is lithiated at position 5, 3-furoic acid at C-2. 2-Methylfuran yields the 5-methylthio-derivative by lithiation and subsequent treatment with dimethyl disulphide. The corresponding phenylthio-compound (28) has been converted into a series of 4-substituted 2-methyl-furans (29 R = alkyl, MeaSi, CO2H, or RCHOH) by the sequence bromi-nation, lithiation, treatment with the appropriate electrophile, and, finally, desulphurization with Raney nickel. 2-Lithiofuran reacts with copper(II)... 

Decanediol 2-Decyl tetradecanoic acid 4,4 -Diaminostilbene-2,2 -disulfonic acid Dihydroxyethyl cocamine oxide Diisobutyl phthalate Dimethyl hydantoin-formaldehyde polymer Dimethyl hydrogenated tallow amine Dimethyl soyamlne Dodecenylsuccinic anhydride Dodecylhexadecanol Ethoxyethanol acetate Ethylene dioleamide Ethylene glycol Ethylene/VA copolymer 2-Ethylhexyl methacrylate 2-Ethylhexyl oleate 2-Furoic acid... 

In 1975, Kellyprepared and characterized a number of polyesters based on 2,5-disubstituted furans in various states of reduction. In this study, 2,5-disubstituted-furan, -dihydrofuran, and -tetrahydrofuran monomers were polymerized using solution, melt-transesterification, ring-opening, and interfacial techniques. These monomers included diacids, diols, diacid chlorides, diesters, dicarboxylic acid anhydrides, as well as monomers based on 5-hydroxymethyl-2-furoic and tetrahydrofuroic acids and esters, and bycyclic lactones containing the tetrahydrofuran ring. A thorough review of previous work done in the area of poljnner synthesis, based on 2,5-disubstituted furan derivatives is reported. It is reported that when... 

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