Die Titelverbindungen (III) (verwandt dem Herbizid Diquat) und (VI) (verwandt dem Herbizid Paraquat) werden dargestellt.

No abstract

Alkaline chlorination of the 4-alkyl-2,6-dichlorophenols (2b) and (2c) proceeds through ring contraction and halolactonization to form the 4α- alkyl-2,2,5α-trichloro-1α,3α-dihydroxycyclopentane-1,4-carbolactones (4b) and (4c). Under similar conditions, 2,4,6-trichlorophenol affords the analogous 2,2,4α,5α-tetrachloro-1α,3α-dihydroxycyclopentane-1,4- carbolactone (4a) in low yield, in addition to the Hantzsch acid (3a) as the major product. The acid (3a) upon further treatment undergoes chloro-lactonization to give the lactone (4a). The structures of the lactones (4b) and (4c) follow from spectroscopic comparison with (4a), the structure of which has been established by X-ray diffraction (C6H4Cl4O4 orthorhombic a 13.485(1), b 12.348(1), c 11.371(1) Ǻ, space group Pccn, Z 8, solved by direct methods and refined by block-diagonal and full-matrix least squares to R 0.031, Rw 0.043 for 1313 unique counter data with I/σ(I) ≥ 3.0).

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In field trials carried our in 1983 at Gama and Horsham (Victoria), Hart (South Australia) and York (Western Australia), the effect of two rates of glyphosate (0.54 and 1.08 kg/ha active ingredient), applied 1-8 days before sowing, on the establishment, growth and nodulation of four cultivars of subterranean clover and 10 medic cultivars was investigated. No significant adverse effects were observed on establishment, growth or nodulation even at the high rate (2x field rate) of glyphosate. The absence of any adverse effect was attributed to rapid absorption and inactivation of glyphosate in soil and possibly also the manner of seed placement below the glyphosate-treated topsoil layer.