
%0 Journal Article
%A Lima, Larissa S. 
%A Barbosa, Luiz Cláudio de A. 
%A de Alvarenga, Elson S. 
%A Demuner, Antônio J. 
%A da Silva, Antônio A. 
%T Synthesis and Phytotoxicity Evaluation of Substituted <emph type="2">para</emph>-Benzoquinones
%J Australian Journal of Chemistry
%D 2003/06/13
%V 56
%N 6
%P 625-630
%K 
%R https://doi.org/10.1071/CH02032
%U https://www.publish.csiro.au/paper/CH02032 
%X Sorgoleone (1) is one of the major constituents of sorghum root exudates. Sorgoleone is an allelochemical that reduces the growth of broad-leaf plants. The 3,5-dimethoxybenzylic alcohol (3) was used as starting material for the synthesis of 2-methoxy-6-(non-1-yl)benzo-1,4-quinone (9) in 69% yield. Acetylation of (9) with acetic anhydride gave the triacetate (10) in 82% yield. The triacetate (10) was then converted in two steps in 2-hydroxy-5-methoxy-3-(non-1-yl)benzo-1,4-quinone (11) and 2-acetoxy-5-methoxy-3-(non-1-yl)benzo-1,4-quinone (12) in 8% and 37% yield, respectively. Quinone (11) was obtained also by reaction of (12) with DBU in 63% yield. Alkylation of (3) and oxidation with chromic anhydride formed the new quinones (16) (17) and (18) in 23%, 16% and 12% overall yield, respectively. The effect of these quinones and sorgoleone (1) at concentrations of 5.5 &#956;g g&#8211;1 on the development of radicle and aerial parts of Cucumis sativus, Brachiaria decumbens, Hyptis lophanta, and Euphorbia heterophylla was tested. 
