2-Furylidene derivatives

The dihydro-cyclopentano-phenanthrene (120) has been synthesized (Scheme 9) from 2-acetyl-3-methylnaphthalene (115), which was converted into the fur-furylidene derivative (116). Treatment with acid afforded the expected dioxo-heptanoic acid (117), which on treatment with base provided the cyclopentenone (118). This keto-acid (118) readily underwent cyclization when boiled with acetic anhydride, furnishing ll-acetoxy-15,16-dihydro-7-methylcyclopenta[a]-phenanthren-17-one (119a). Deoxygenation at C(ll) was performed through... 

Furaldehyde ( furfural ) reacts with methyl a-D-mannopyranoside yielding mono- and di-O-furylidene derivatives 168) which have both... 

Further information on the environment about the carbonyl group was obtained in two other reactions. It was shown that XXVI formed a furylidene derivative which on ozonolysis and decarboxylation was converted into the dicarboxylic acid XLIII. Oxidation of XL by periodate-permanganate gave formic acid and succinic acid, the former originating from C-6 and the latter apparently in the chain C-1—C-4. The peripheral structure of the molecule was then defined and only two sites, C-12 and C-13, were available for attachment of the bridge provided that annotinine has a bridged hydrojulolidine structure. 

Synthesis (Kleemann et al. 1999, Janssen (Janssen), 1973 Janssen et al. (Janssen), 1973, Stokbroekx et al., 1973, Niemegeers et al., 1974) ) Treatment of 2-oxo-3,3-diphenyl-tetrahydrofuran, synthesized by treatment of diphenyl-acetic acid ethyl ester with ethylene oxide, with HBr(gas) yields bromo derivative i, which is then converted into butyryl chloride derivative ii by means of thionyl chloride in refluxing chloroform. Reaction of derivative ii with dimethylamine in toluene affords dimethyl (tetrahydro-3,3-diphenyl-2-furylidene)ammonium bromide, which is then condensed with 4-(4-chlorophenyl)-4-piperidinol by means of Na2C03 and Kl in refluxing 4-methyl-2-pentanone to provide loperamide. 

Although some derivatives, particularly the furylidene compound, are more effective for some purposes, none of the more complex triazole derivatives patented as herbicides has been able to displace aminotriazole. 

A series of heterocycle derivatives of 1,1-bis-phosphonate (222), (223), (224) and (225) has been synthesized by Michael addition of 1,1-methylene bis-phosphonate to acceptors such as 5-arylidene rhodamines, 5-benzylidene-2-thiohydantoin, benzylidene or 2(2 -furyliden)-cyanomethyl-l,3-benzothiazoles... 

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