Furan 3- phenyl-, ring synthesis

Fig. 3. Design strategy for the synthesis of prazosin-related quinazolines by inserting a substituent on the furan ring of 2 or 3 or by replacing the furan ring of 2 with an (un)substituted phenyl ring. See Table 2 for structures.

The fast fade rate shown by 2-(4-trifluoromethyl)-2-phenyl-5-trifluorophenyl-[l]benzofuran[2,3-(]naphtho[l,2-6]pyran is attributable to the bulky 5-substituent rather than to the fused benzofuran ring <01WOP36424>. Its synthesis follows from the preparation of 9-hydroxy-7-trifluoromethylbenzo[6]naphtho[ f]furan from 4-chloromethyldibenzofuran (Scheme 18). 

The synthesis of furan fatty esters containing a phenyl substituent at the 3- or 4-position of the furan ring was reported these involved methyl 9,10-epoxy-12-oxostearate as a key intermediate (85). The mono-, di-, and triacylglycerols of a Cj g furan fatty acid were prepared by chemical and enzymatic means (86). Furanoacety-lene phytoalexins (wyerone [19] and dihydro-wyerone [20]) were prepared in multigram quantities from furfural (87). The synthesis route of compound [19] is presented in Scheme 6. 

Radical Substitution.—The reactions of 3-benzo[6]thienyl radicals generated by the photolysis of 3-iodobenzo[Z>]thiophen have been studied in a variety of monosubstituted benzenes as solvent. Isomer ratios were determined, and the results indicate that the 3-benzo[6]thienyl radical has a reactivity intermediate between those of 2- and 3-thienyl radicals. The homolytic phenylations of benzo[6]thiophen and benzo[6]furan have been compared. Thermal decomposition of )V nitrosoacetanilide was the source of phenyl radicals. Whereas homolytic substitution in benzo[6]-furan occurs almost exclusively in the heterocyclic ring, benzo[6]thiophen shows comparable reactivity in all positions. The synthesis of all six isomeric phenyl benzo[6]thiophens is given. ... 

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