Furanones benzo

The direct combination of selenium and acetylene provides the most convenient source of selenophene (76JHC1319). Lesser amounts of many other compounds are formed concurrently and include 2- and 3-alkylselenophenes, benzo[6]selenophene and isomeric selenoloselenophenes (76CS(10)159). The commercial availability of thiophene makes comparable reactions of little interest for the obtention of the parent heterocycle in the laboratory. However, the reaction of substituted acetylenes with morpholinyl disulfide is of some synthetic value. The process, which appears to entail the initial formation of thionitroxyl radicals, converts phenylacetylene into a 3 1 mixture of 2,4- and 2,5-diphenylthiophene, methyl propiolate into dimethyl thiophene-2,5-dicarboxylate, and ethyl phenylpropiolate into diethyl 3,4-diphenylthiophene-2,5-dicarboxylate (Scheme 83a) (77TL3413). Dimethyl thiophene-2,4-dicarboxylate is obtained from methyl propiolate by treatment with dimethyl sulfoxide and thionyl chloride (Scheme 83b) (66CB1558). The rhodium carbonyl catalyzed carbonylation of alkynes in alcohols provides 5-alkoxy-2(5//)-furanones (Scheme 83c) (81CL993). The inclusion of ethylene provides 5-ethyl-2(5//)-furanones instead (82NKK242). The nickel acetate catalyzed addition of r-butyl isocyanide to alkynes provides access to 2-aminopyrroles (Scheme 83d) (70S593). 

Benzo[b]furan-4(5H)-one, 6,7-dihydro-synthesis, 4, 710 Benzofuranones H NMR, 4, 579 Benzo[b]furanones from 3-hydroxyflavanone, 3, 729 Benzo[b]furan-2(3H)-ones — see 2-Coumaranones Benzo[b]furan-3(2H)-ones IR spectra, 4, 590 reactions, 4, 650 Benzo[ c]furan-1 (3 W) -ones carbanions, 4, 579 H NMR, 4, 579 reactions with arynes, 1, 415 structure, 4, 552... 

Chemical Name succinic acid monoester with 4-[2-(1-hydroxyethyl)-3-methyl-5-benzo-furanyl] -2(5H)-furanone... 

Photocyclization in benzene of p-quinones with an acetaldehyde group, such as 2-(l,4-benzoquinonyl)-2-methylpropionaldehyde, gives 5-hydroxy-3-methylbenzofuran, 3,3-dimethyl-5-hydroxy-2(3f/)-benzo-furanone and the cyclic hemiacetal of 2-(2,5-dihydroxyphenyl)-2-methylpropionaldehyde.322... 

Step 1 analogues 6-hydroxy-2-(4-hydroxyphenyl)-3-[4-(2-dimethylamino-ethoxy) benzoyl]benzo[/3]thiophene, (I), and 2(5H)-furanone derivatives have been prepared and are described (1), (2), respectively. 

In the 3-phenyl-2(3 )-benzofuranone series, we find a long-known spasmolytic compound, 3-(2-diethylamino)ethyl-3-phenyl-2(3fI)-benzo-furanone (Amolanone), which also has analgesic properties. A novel compound, 2-(l-succinyloxy)ethyl-3-methyl-5-(2-oxo-2,5-dihydro-4-furyl)benzofuran or Benfurodil (25) (clinical name Eudilat), is a vasodilator and cardiotonic. 

The irradiation of the 6-methoxybenzofuran 2,3-dione (200) in the presence of styrene affords 3-(2-hydroxy-4-methoxyphenyl)-4-phenyl-2(5H)-furanone as one of the products. 2,3 Dimethylbut-2-ene and 2-methylpropene undergo photoaddition to the C9-C10 double bond of 2H,8H-benzo[l,2-b 3,4-b ]dipyran-2,8-dione. The indanetrione (201) yields an oxetane when irradiated in the presence of the ethene (202) or 2-methylbut-2-ene, but hydrogen abstraction reactions predominate when the alkene is 2,4,4-trimethylpent-l-... 

The conversion of dihydrofurans and their benzologues into the aromatic compounds has been the subject of a large number of investigations. For example, the treatment of benzo[c]furanone... 

Azoxystrobin is built up in an elegant and convergent synthesis from three building blocks 3-(methoxymethylene)-benzo-2(3ff)-furanone, 4,6-dichloropyrim-idine and 2-hydroxybenzonitrile. [61,62]... 

Another recently introduced group of alkyl radical trapping agents is the benzo-furanone derivatives (Pitteloud and Dubs, 1994) ... 

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