Photodehydrocyclizations of stilbene-like compounds VIII: Synthesis of hexaheliceno[3,4-c]hexahelicene
The synthesis of a new double helicene, hexaheliceno[3,4-c]hexahelicene, has been described. Of two possible diastereomers only one has been obtained. Presumably the product has the racemic configuration but this assignment is not yet definite.
Conformational studies on hexahelicenes—III: Synthesis and spectroscopic data of meso- and rac.-2,2′-Bis hexahelicyl
Abstract 2,2′-Bis-hexahelicyl has been synthesized and separated into meso and racemic forms. Analysis of the NMR spectra of both forms in CS2 as well as AsCl3 revealed that the central biphenylic part of the meso compound is rather planar, whereas in the racemic compound both halves of the molecule have been twisted around the central bond.
Interaction of Diclofop-Methyl and MCPA on Wild Oats (Avena fatua)
Diclofop-methyl {methyl 2-[4-(2,4-dichlorophenoxy)phenoxy] propanoate} loses part of its activity on wild oats (Avena fatua L.) when it is applied in combination with ester or amine formulations of MCPA {[4-chloro-o-tolyl)oxy] acetic acid.} Uptake of diclofop-methyl is reduced in the presence of commercial formulations of MCPA, particularly amine formulations, which are only partly compatible with the diclofop-methyl formulation. With added MCPA, regardless of formulation, hydrolysis of diclofop-methyl to the acid diclofop is slowed down, both in intact wild oat plants and in a crude leaf extract. At the same time, conversion of any acid formed to inactive conjugates is accelerated in the presence of MCPA. It is concluded that the loss of activity of diclofop-methyl by MCPA can be accounted for by the effects of MCPA on uptake and metabolic conversion of diclofop-methyl.