2-Furancarboxylic acid → HCID 19874619, Verbindung
Reaktionsgleichung
[F:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[CH:12]=[CH:11][O:10][C:9]=2[C:13]([OH:15])=O)=[CH:4][CH:3]=1.O1C=CC=C1C(O)=O.[Cl-].[Al+3].[Cl-].[Cl-]>>[F:1][C:2]1[CH:3]=[CH:4][C:5]2[C:8]3[CH:12]=[CH:11][O:10][C:9]=3[C:13](=[O:15])[C:6]=2[CH:7]=1Komponenten
4
Versuchsvorschrift
Synthetic substrates 8H-indeno[2,1-b]furan-8-one and 8H-indeno[2,1-b]furan and their derivatives are prepared in accordance with the following. Substituted and unsubstituted 3-arylfuran-2-carboxylic acids are prepared according to a general procedure of Burgess, J. Org. Chem., 21, 102 (1956), wherein, 4,5-dimethoxy-1-phenyl-2-butanone and related 2' to 4' substituted phenyl analogs (e.g., 4,4-dimethoxy-1-(4'-fluorophenyl)-2-butanone, prepared according to the general procedure of Royals and Brannoch, J. Amer. Chem. Soc., 75, 2050 (1953)) are converted into 3-phenylfuran-2-carboxylic acid methyl ester (e.g., 3'-(4'-fluorophenylfuran-2-carboxylic acid methyl ester) by the Darzens glycidic ester condensation (Darzens, Compt. Rend., 139, 1214 (1904)). This rearrangement of the glycidic ester yields the furoic ester. The furoic ester can be hydrolyzed in alkaline methanolic solution to yield, for example, 3-(4'-fluorophenyl)-furan-2-carboxylic acid. The furoic acid product can be cyclized via the aroyl chloride in the presence of stannic chloride or aluminum chloride to yield the ketone, e.g., 6-fluoro-8H-indeno [2,1-b]furan-8-one. This ketone can be derivatized in accordance with Method V. Hydantoin derivatization (Method I) yields the spiro-hydantoin, e.g., spiro-(6-fluoro-8H-indeno[2,1-b]furan-8,4'-imidazolidine)-2',5'-dione. Reduction according to methods cited in Method VIII yields the corresponding 8H-indeno[2,1-b]furan derivative which can be derivatized in accordance with Methods II, III and IV into the corresponding spiro-thiazolidinedione, spiro-oxazolidinedione and spiro-succinimide. Furthermore, the spiro-derivatives may be further derivatized according to Method VI.