References to syntheses of the 2'-, 3 '-, 4'-, 5, and 6-monomethyl derivatives of 3, 4- benzpyrene have been summarized in a paper'reporting the synthesis of a sixth isomer (9- methyl). In the series of monohydroxy compounds, the 4'-, 2 5-3 and 6-4isomers have been synthesized for biological testing. Apart from the preparation of 5-derivatives by direct substitution of the hydrocarbon, these substances have been produced by syntheses in ...