As part of an ongoing program on the chemistry and biological activity of N-oxide-containing molecules, a number of novel 1,2, 5-oxadiazole N-oxide, benzo[1,2-c]1,2,5-oxadiazole N-oxide, and quinoxaline N,N'-dioxide derivatives were synthesized and evaluated for their herbicidal activity. Many of these compounds exhibited moderate to good herbicidal pre-emergence activity against Triticum aestivum. Dose-response studies were done on the more representative compounds (12, 20, and 26). The most active compound, butylcarbamoylbenzo[1,2-c]1,2,5-oxadiazole N-oxide, 26, displayed herbicidal activity at concentrations as low as 24 g/ha.

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É descrita uma síntese eficiente de um aduto de Diels-Alder da tetrametilpurpurogalina (TMPG) e o nitrosobenzeno (NOB). A cinética da decomposição térmica do aduto, que segue um mecanismo de retro-Diels-Alder foi estudada usando espectroscopía de 1 H-RMN.An efficient synthesis of a Diels-Alder adduct between purpurogallin tetramethyl ether (TMPG) and nitrosobenzene (NOB) is reported. The thermal decomposition kinetics of the adduct, which follows a retro-Diels-Alder mechanism, was studied using 1 H-NMR spectroscopy.

Olefination Olefination O 0284 Solvent Effect in the Wittig Reaction under Boden's Conditions. -An interesting change in the stereochemical outcome of the Wittig olefination in the presence of K2CO3 as base and catalytic amounts of 18-crown-6 is reported. This effect depends significantly on the nature of the ylide and the polarity of the solvents. -(PANDOLFI*, E. M.; LOPEZ, G. V.; DIAS, E.; SEOANE, G. A.; Synth. Commun. 33 (2003) 13, 2187-2196; Dep. Org. Chem., Fac. Chem., Univ. Rep., 11800 Montevideo, Urug.; Eng.) -H. Haber 42-056

The crystal structure of the adduct, C21H21NO2, of tetra­methyl­purpurogallin with nitro­so­benzene is reported. The compound exhibits a [3.2.2] bicyclic system corresponding to two seven‐membered rings and one six‐membered ring in distorted chair, boat and twist–boat conformations, respectively. One intramolecular and two intermolecular hydrogen bonds direct the packing and stabilize the mol­ecule.

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The structure of the adduct of eucarvone with nitro­so­benzene, C16H19NO2, is reported. The [3.2.2] bicyclic system corresponds to two seven‐membered rings in boat and distorted chair conformations and a six‐membered ring that adopts a distorted boat conformation. No conjugation is observed between the phenyl group and the N—O system. The packing is directed mainly by a C⋯O hydrogen bond, C—H⋯O‐(1 − x, −y, z) and by intermolecular C—H⋯π interactions.