Preparation of substituted benzamides.

摘要

Benzamides of the formula (I):
<Chemistry id="chema01" num="0001"><Image id="ia01" he="11" wi="77" file="IMGA0001.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>in which Ar is optionally substituted aryl; X is 0, S or NH and R is optionally substituted alkyl or alkenyl when X is 0 or S, or is optionally substituted alkenoyl when X is NH, are prepared by
<UnorderedLists id="ula01" listStyle="none"><ListItem>(a) reacting a compound of the formula (II):
<Chemistry id="chema02" num="0002"><Image id="ia02" he="6" wi="78" file="IMGA0002.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>with a brominating agent in a solvent which is substantially chemically inert to the reactants and in which compound (II) is soluble, to form a compound of the formula (III):
<Chemistry id="chema03" num="0003"><Image id="ia03" he="17" wi="79" file="IMGA0003.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>and</ListItem><ListItem>(b) reacting the compound (III) with a compound RXH. Preferably, bromination is carried out rapidly in dried ethyl acetate.</ListItem></UnorderedLists>

The process avoids hydration of the CN group of the compound (III) to a carbamoyl group obviating a subsequent dehydration step later.

The intermediate compound (III) is novel.

The substituted benzamides are useful as herbicides and fungicides.