THE SYNTHESES AND REACTIONS OF ALKYLATED FURANS

The reaction of 2-chloromercurifuran with t-butyl bromide does not yield 2-t-butylfuran. Instead 2,5-di-t-butylfuran, 2,2,7,7-tetramethyloctane-3,6-dione, and 2-t-butyl-5-[2,4,4-trimethyl-2-pentyl]furan are produced. Air-oxidation of di-t-butylfuran yields trans-2,2,7,7-tetramethyl-4-octene-3,6-dione (converted to the cis isomer photochemically) which forms a dibromide identical with the dibromo substitution product from tetramethyloctanedione. Cold nitric acid oxidation of di-t-butylfuran or tetramethyloctanedione yields 4-hydroxy-5-isonitroso-2,2,7,7-tetramethyloctane-3,6-dione, but hot nitric acid oxidation of the tetramethyloctanedione yields the expected 2-trimethylacetyl-5-t-butylisoxazole. The corresponding oxidation product of t-butyltrimethylpentylfuran has not been identified, although it yields 2,2,4,4-tetramethylpentanoic acid, indicative of the isoöctyl substituent, upon hydrolysis. The same acid is obtained by permanganate oxidation of Friedel–Crafts-synthesized 2,5-di-[2,4,4-trimethyl-2-pentyl]furan, a compound which yields trans-2,2,4,4,9,9,11,11-octamethyl-6-dodecene-5,8-dione.