Synthèses dans le domaine des hydrocarbures cancérigènes V. 4′méthyl‐et 4′,9,10‐triméthyl‐1,2‐benzanthracènes

I) A new synthesis of 4′‐methyl‐1,2‐benzanthracene (XII) starting from 1‐naphthaldehyde, is described. This synthesis involves the following steps: bromination (5‐bromo‐1‐naphthaldehyde), Wolff‐Kischner reduction (5‐bromo‐1‐methylnaphthalene), Grignard condensation with phthalic anhydride (5′‐methyl‐α‐naphthoyl‐o‐benzoic acid), cyclisation (4′‐methyl‐1,2‐benzanthraquinone), reduction (4′‐methyl‐1,2‐benzanthracene). II) 4′9,10‐trimethyl‐1,2‐benzanthracene (III) has been prepared: a) By a Grignard reaction between methyl‐magnesium iodide and 4′‐methyl‐1,2‐benzanthraquinone (see above) by the method of Sandin and Fieser. b) starting from 1,2‐benzanthraquinone by the following steps: bromination (4′‐bromo‐1,2‐benzanthraquinone), Grignard condensation with methyl‐magnesium iodide (4′‐bromo‐9,10‐dimethyl‐1,2‐benzanthracene) treatment with C4 H9 Li and (CH3)2 SO4 (4′, 9, 10‐trimethyl‐1,2‐benzanthracene). Copyright © 1952 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim