Pyrogallol dimethyl ether is found in beechwood tar.
Meta-aminophenol is prepared by reducing metanitrophenol, or by heating resorcin with ammonium chloride and ammonia to 200° C. Dimethyl-meta-aminophenol is prepared by heating meta-aminophenol with methyl alcohol and hydrochloric acid in an autoclave; by sulphonation of dimethylaniline, the sulphonic acid formed being finally fused with potash; or by nitrating dimethylaniline, in the presence of sulphuric acid at 0° C. In the latter case a mixture of nitro-compounds is obtained which can be separated by the addition of sodium carbonate.
Dimethyl-meta-aminophenol crystallizes in small prisms which melt at 87° C. It condenses with phthalic anhydride to form rhodamine, and with succinic anhydride to rhodamine S.
Its tetramethyl-diamino derivative, which is formed by condensing formaldehyde with dimethyl-meta-aminophenol and subsequent elimination of water from the resulting diphenyl methane derivative, is the leuco base of pyronine, into which it passes by oxidation.
Aniline, C 6 H 5 NH 2, monomethyl aniline, C 6 H 5 NH CH 3, and dimethyl aniline, C 6 H 5 N(CH 3) 2, are in increasing order of basicity.