1667-05-6

Upstream product

• 67396-82-1 3-chloro-2,4,6-trimethylaniline 
• 67-56-1 methanol 
• 527-60-6 Mesitol 
• 87025-08-9 4-bromo-2,4,6-trimethylcyclohexa-2,5-dienone 
• 4906-82-5 6-acetoxy-2,4,6-trimethyl-cyclohexa-2,4-dienone 
• 70264-66-3 4-chloro-2,4,6-trimethylcyclohexa-2,5-dienone 
• 1667-04-5 2-bromomesitylene 
• 67396-77-4 2-chloro-1,3,5-trimethyl-4-nitrobenzene 
• 93116-01-9 Phosphorsaeure-<3-chlor-2,4,6-trimethyl-phenylester> 

Downstream Products

• 28480-74-2 3,4-dichloro-2,4,6-trimethylcyclohexa-2,5-dienone 
• 67396-83-2 3-Chloro-2,4,6-trimethylphenylacetat 

Relevant academic research and scientific papers

ipso Halogenation. II. Bromination of phenols, isomerisation and disproportionation of bromophenols, and dione-phenol rearrangement of bromodienones

Bromination of p-cresol, bromo-p-cresol, 3,4-dimethylphenol, and mesitol in trifluoromethanesulfonic acid gices as the main product the bromo derivative with bromine meta to hydroxyl, a result attributed to the intermediate formation of a bromodienone and its rearrangement.Phenols does not give m-bromophenol in trifluoromethanesulfonic acid. 4-Bromo-2,4,6-trimethylcyclohexa-2,5-dienone rearranges to 3-bromomesitol in trifluoromethanesulfonic acid and, similarly, 2,4,6-tribromo-4-methylcyclohexa-2,5-dienone rearranges to 3-bromomesitol in trifluoromethanesulfonic acid and, similarly, 2,4,6-tribromo-4-methylcyclohexa-2,5-dienone rearranges to 2,3,6-tribromo-4-methylphenol.Under appropriate conditions debromination of bromodienones is competitive with rearrangement.Tetramethylammonium bromide in trifluoromethanesulfonic acid is an effective reagent for isomerization and disproportionation of bromophenols.Tetramethylammonium iodide in trifluoromethanesulfonic acid is an effective reagent for selective debromination of bromophenols at the ortho and para position.

Electrophilic Chlorination of 4-Methylphenols with Molecular Chlorine. Synthesis of Dimethoxy Aromatics by Methanolysis of 4-Chloro-4-methylcyclcohexa-2,5-dienones

The chlorination of p-cresol (1a), 2,4-dimethylphenol (1b), 3,4-dimethylphenol (1c), 2,4,5-trimethylphenol (1d), 2,4,6-trimethylphenol (1e) and the various possible mono- and dichloro derivatives of these phenols (3a-d, 6a and 6 c) with molecular chlorine was investigated in dichloromethane or dimethyl formamide solution.The 2,6-substituted p-cresol derivatives all give quantitative yields of 4-chloro-4-methylcyclohexa-2,5-dienones (5b, 5d, 7a, 7c and 2e), whereas the less substituted p-cresol derivatives give a 20-25percent yield of corresponding 4-chloro-4-methylcyclohexa-2,5-dienones (2a-d, 5a and 5c), the other products being chlorinated phenols.Treatment of 4-chloro-4-methylcyclohexa-2,5-dienones with at least one of the double bonds of the ring unsubstituted (2a-c and 4a) with methanol gave a quantitative yield of a 1,3-dimethoxybenzene derivative (9a-c and 10), whereas similar treatment of 4-chloro-2,4,5-trimethylcyclohexa-2,5-dienone (2d) gave 5-methoxy-2,3-dimethylbenzyl methyl ether (11).Treatment of the other 4-chlorodienones with methanol gave the corresponding 4-methoxydienones.Electrophilic chlorination of certain p-cresol derivatives followed by methanolysis hence is a facile although low-yield method for 3-methoxylation or selective side chain oxidation of these p-cresol derivatives.