Constituents of high-boiling petroleum distillates. Part XII. Isolation and synthesis of some methylanthracenes

Abstract

Two hydrocarbons previously isolated from a Kuwait mineral oil have been identified as 1,3,6,8- and 1,4,5,8-tetramethylanthracene. 1,3,6,7- and 2,3,6,7-Tetramethylanthracene have been isolated from a high-boiling fraction of an Oklahoma oil. Syntheses of 1,3,6- and 1,3,7-trimethyl-, and of 1,3,5,7-, 1,3,6,8-, and 1,4,5,8-tetramethyl-anthracene are described. The 1,3,6-trimethyl- and 1,3,6,8- and 1,4,5,8-tetramethyl compounds are incorrectly described in the literature.

The chemical shift of the methyl protons of a methyl-substituted anthracene depends on the position of attachment of the group to the nucleus and may provide a useful aid in the identification of an unknown polymethyl-anthracene.