Synthesis of new phytogrowth-inhibitory substituted aryl-p-benzoquinones.
Reaction of [(2-alkyloxy)methyl]-1,4-dimethoxybenzene 10 (alkyl=butyl, hexyl, decyl, tridecyl, tetradecyl, hexadecyl, and octadecyl) with ceric ammonium nitrate in order to produce p-benzoquinones (=cyclohexa-2,5-diene-1,4-diones) afforded 5-[(alkyloxy)methyl]-2-(4-formyl-2,5-dimethoxyphenyl)benzo-1,4-quinones 12a-12g in yields that varied from 46 to 97%, accompanied by 2-[(alkyloxy)methyl]benzo-1,4-quinones 11a-11g in only small quantities (< or =5%). These quinones resemble the natural phytotoxic compound sorgoleone, found in Sorghum bicolor. This reaction exemplifies a general procedure for the synthesis of novel aryl-substituted p-benzoquinones. The selective effects of compounds 12a-12g, at the concentration of 5.5 ppm, on the growth of Cucumis sativus, Sorghum bicolor, Euphorbia heterophylla, and Ipomoea grandifolia were evaluated. All compounds caused some inhibition upon the aerial parts and root growth of the tested plants. The most active compound, 2-(4-formyl-2,5-dimethoxyphenyl)-5-[(tridecyloxy)methyl]-benzo-1,4-quinone (12d), caused between 3 and 18%, and 12 and 29% inhibition on the roots and aerial parts development of Cucumis sativus and Sorghum bicolor, respectively, and between 77 and 85%, and 34 and 52% inhibition on the roots and aerial parts growth of Euphorbia heterophylla and Ipomoea grandifolia, respectively.
de Almeida Barbosa
Luiz Cláudio
LC
Departamento de Química, Universidade Federal de Viçosa, 36571-000, Viçosa--MG, Brazil. lcab@ufv.br <lcab@ufv.br>
de Alvarenga
Elson Santiago
ES
Demuner
Antônio Jacinto
AJ
Virtuoso
Luciano Sindra
LS
Silva
Antônio Alberto
AA
D016227:Benzoquinones / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D001592:Benzyl Alcohols / Q000737:chemistry; D018553:Cucumis sativus / Q000187:drug effects / Q000254:growth & development; D028481:Euphorbia / Q000187:drug effects / Q000254:growth & development; D027741:Ipomoea / Q000187:drug effects / Q000254:growth & development; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010084:Oxidation-Reduction; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development*; D045868:Sorghum / Q000187:drug effects / Q000254:growth & development
D016227:Benzoquinones; D001592:Benzyl Alcohols; C004532:quinone