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Regiospecific Photochemical Synthesis of Methylchrysenes.

ABSTRACT: Methylated polycyclic aromatic hydrocarbons (PAHs) are suspected to be some of the toxic compounds in crude oil towards marine life and are needed as single compounds for environmental studies. 1-, 3- and 6-methylchrysene (3a,b,c) were prepared as single isomers by photochemical cyclization of the corresponding stilbenoids in the Mallory reaction using stoichiometric amounts of iodine in 82-88% yield. 2-methylchrysene (3d) was prepared by photochemical cyclization where the regioselectivity was controlled by elimination of an ortho-methoxy group under acidic oxygen free conditions in 72% yield. These conditions failed to form 4-methylchrysene from the corresponding stilbenoid. All stilbenoids were made from a common naphthyl Wittig salt and suitably substituted benzaldehydes. We have also demonstrated that methylchrysenes can be oxidized to the corresponding chrysenecarboxylic acids by KMnO₄ in modest yields.

SUBMITTER: Bohme T

PROVIDER: S-EPMC9822284 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature

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Regiospecific Photochemical Synthesis of Methylchrysenes.

Böhme Thomas T Egeland Mari M Lorentzen Marianne M Mady Mohamed F MF Solbakk Michelle F MF Sæbø Krister S KS Jørgensen Kåre B KB

Molecules (Basel, Switzerland) 20221228 1

Methylated polycyclic aromatic hydrocarbons (PAHs) are suspected to be some of the toxic compounds in crude oil towards marine life and are needed as single compounds for environmental studies. 1-, 3- and 6-methylchrysene (<b>3a,b,c</b>) were prepared as single isomers by photochemical cyclization of the corresponding stilbenoids in the Mallory reaction using stoichiometric amounts of iodine in 82-88% yield. 2-methylchrysene (<b>3d</b>) was prepared by photochemical cyclization where the regiose ...[more]

PMID: 36615430

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