Hydro quinone dimethyl ether

Figure 23. Component dipole moments of p-chloroanisole and of hydro-quinone-dimethyl ether.

Fig. 4. Valence angle at the oxygen atom in hydro-quinone dimethyl ether.

Obtained (poor yield) by reaction of 2,3,4, 5-tetramethoxy-benzoyl chloride with hydro-quinone dimethyl ether in benzene in the presence of aluminium chloride (16%) [1160]. 

It should be noted that NBS can cause nuclear bromination when that reaction occurs readily. In the absence of a catalyst it can brominate the nucleus of condensed aromatic compounds such as naphthalene, anthracene, and phenanthrene,399 veratrole, the dimethyl ethers of resorcinol and hydro-quinone,389 and pyrogallol trimethyl ether.390 Pyrocatechol and 2 moles of NBS afford 4,5-dibromopyrocatechol resorcinol and 3 moles of NBS afford 2,4,6-tribromoresorcinol 391,392 and anthranilic or o- or/ -hydroxybenzoic acid with 2 moles of NBS afford the 4,5- or 3,5-dibromo derivatives.391-393 However, nuclear bromination of benzene and toluene is effected by NBS only if equimolar amounts of A1C13, ZnCl2, FeCl3, or H2S04 are added. 

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