2.5- Dimethylfuran 2,5-DMF

The [ 02]°. values shown in Fig. 16.4 were determined by using furfuryl alcohol (FFA, I) as a probe compound (Haag et al., 1984a). Another frequently used trapping agent for l02 determination is 2,5-dimethylfuran (2,5-DMF, II) (Zepp et al., 1977) ... 

Anodic acetoxylation of furan can be done in acetic acid containing acetate [173, 174] and benzoyloxylation in DMF containing benzoic acid and lithium chloride [175]. A mixture of cis- and ra 5-benzoyloxylated product is formed. Cyanomethoxylation of 2,5-dimethylfuran gives a mixture of cis- and rmn5-2-cyano-5-methoxy-2,5-dimethyldihydro-furan [176-178]. 

Furanophane (27) is reduced by hydrogen and PtOa catalyst to (119) (2,5-dimethylfuran is reduced under the same conditions to 2-hexanol) and is converted by bromine in methanol to the polyketal (120) (60JA1428), which is easily hydrolyzed to (121) (77M331). The mixed heterophane (122) was hydrolyzed to (123) (77H(7)8l). As anticipated, electrophilic substitution favors a-substitution (78M137), and (124) undergoes formylation (POCI3/DMF) to afford (125) (77M233). 

Both indirect and direct approaches for the determination of (j) have been applied. Early methods employed the highly reactive substrates tetramethyl-ethylene (TME) (96), 2,5-dimethylfuran (DMF) (96,97), and 1,3-diphenyliso-benzofuran (DPBF) (48,67,85,93,94) to trap 02( Ag) ... 

The indirect 3-alkylation of 2,5-dimethylfuran was achieved via a tandem Michael addition of a nitroalkane and elimination of nitrous acid starting from cis-3-hexene-2,5-dione, a ring opening product of 2,5-diraethylfuran. Hydrogenation of the carbon-carbon double bond and a subsequent Paal-Knorr reaction provided 3-substituted-2,5-dimethylfurans <01S2003>. Selective ring bromination of methyl 2-methyl-3-furoate with NBS was realized when DMF, an aprotic polar solvent, was used. If the same reaction was carried out in CCI,... 

For example, using an acidic H-ZSM-5 with Si/Al = 300 at 350 °C 2,5-dimethylfuran DMF is produces with 96.1 % yield at 99.8 % conversion of acetonylacetone. On the other hand, if this zeolite is doped with alkali ions in excess of their framework Al-content (Si/Al = 300, Na/Al = 7.6) then 89.1 % yield of methylcyclopentenone MCP is obtained at quantitative conversion. Only a 4.4 I yield of DMF is. observed using that basic zeolite catalyst. The number of alkali ions which are in excess of the corresponding Al content of the zeolite framework are associated with the internal silyloxy groups in the as - synthesized form of high silica zeolites. The behaviour of such a Na-ZSM-5 is very much like sodium silicalite. 

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