反应详情

In the synthesis shown in Scheme 1, a 3-nitrobenzene, generated from a 6-nitro-anthranilic acid (A), is reacted with a cyclic 1,4-diene (B), such as 5-isopropyl-cyclopentadiene, to form a 5-nitro-benzonorbornadiene (C) in a Diels-Alder reaction. Under standard catalytic reduction conditions (for example, using Raney nickel or palladium on carbon in a solvent such as methanol), both the 5-nitro group and the 2,3-double bond of the 5-nitro-benzonorbornadiene (C) are reduced to form the 5-amino-benzonorbornene (D). Reaction of the 5-amino-benzonorbornene (D) with a heterocyclyl-carboxylic acid or heterocyclyl-carboxylic acid derivative (E), where Q may be hydroxyl, fluoro, chloro or bromo, in a solvent such as dichloromethane gives a fungicidal heterocyclyl-carboxylic acid benzonorbornen-5-yl-amide (F). An example of (D) is 5-amino-9-isopropyl-benzonorbornene, which is a precursor of an amide of, for example, 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid.