title: Synthesis of new aliphatic and aromatic phytotoxic derivatives of 2alpha,4alpha-dimethyl-8-oxabicyclo[3.2.1]oct-6-en-3-one.
abstract: Several new compounds with potential herbicidal activity were synthesized from 2alpha,4alpha-dimethyl-6,7-exo-isopropylidenedioxy-8-oxabicyclo[3.2.1]octan-3-one (4). Seven aromatic alcohols were prepared by reaction of (4) with aryllithium reagents, where the aryl groups were 4-ethoxyphenyl (5, 70% yield), 4-ethylphenyl (6, 82% yield), 4-butylphenyl (7, 78% yield), 4-tert-butylphenyl (8, 81% yield), 2,4-dimethoxyphenyl (9, 75% yield), 2-ethylphenyl (10, 12% yield) and para-(4-bromophenoxy)phenyl (11, 24% yield). Reaction of the acetonide (4) with Grignard reagents formed also four aliphatic alcohols where the alkyl groups are ethyl (13, 78%), butyl (14, 85%), hexyl (15, 81%) and octyl (25, 92%). The alcohols (5), (6), (7), (8), (13), (14), (15) and (25) were reacted with thionyl chloride in pyridine, forming their respective alkenes (17, 76%), (18, 74%), (19, 83%), (20, 73%), (22, 78%), (26, 62%), (23, 77%) and (24, 66%). The effect of these compounds, at the concentration of 5.5 microg g(-1), on the development of radicle and aerial parts of Sorghum bicolor (L) Moench, Euphorbia heterophylla L, Brachiaria decumbens and Desmodium tortuosum DC was evaluated.
authors.affiliation: Departamento de Química, Universidade Federal de Viçosa, 36571-000, Viçosa-MG, Brazil. lcab@ufv.br
authors.forename: Luiz C de A
authors.initials: LC
authors.lastname: Barbosa
authors.forename: Elson S
authors.initials: ES
authors.lastname: de Alvarenga
authors.forename: Antônio J
authors.initials: AJ
authors.lastname: Demuner
authors.forename: Remilson
authors.initials: R
authors.lastname: Figueiredo
authors.forename: Antônio A
authors.initials: AA
authors.lastname: da Silva
mesh_terms: D035201:Brachiaria / Q000187:drug effects; D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis* / Q000633:toxicity; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D028481:Euphorbia / Q000187:drug effects; D007887:Fabaceae / Q000187:drug effects; D006540:Herbicides / Q000138:chemical synthesis* / Q000633:toxicity; D006841:Hydrocarbons, Aromatic / Q000138:chemical synthesis / Q000633:toxicity; D009682:Magnetic Resonance Spectroscopy; D019684:Magnoliopsida / Q000187:drug effects*; D015394:Molecular Structure; D018517:Plant Roots / Q000187:drug effects; D018520:Plant Shoots / Q000187:drug effects; D006109:Poaceae / Q000187:drug effects
chemical_list: C481014:2alpha,4alpha-dimethyl-6,7-exo-isopropylidenedioxy-8-oxabicyclo(3.2.1)octan-3-one; D001643:Bridged Bicyclo Compounds; D006540:Herbicides; D006841:Hydrocarbons, Aromatic