| 摘要 |
<p>Prepn. of halobenzenes of formula (I) is described. In the formula, R1 and R4 are each halo; R3 is NO2 or COOR5 (where R5 is H, or a (cyclo)aliphatic, araliphatic or aromatic gp.), R4 can also be H, or when R3 is COOR5, R4 can be NO2. Process comprises (i) reacting an aniline of formula (III) with a halogenating agent in the presence of H2O and an acid, giving a haloaniline of formula (II); and (ii) without isolating the reaction mixt., reacting cpd. (II) with (cyclo)aliphatic or araliphatic alcohols and nitrating agents in the presence of an acid, and with addn. of H2O, at 35 degrees C. Cpd. (I) can also be prepd. by reacting a haloaminobenzoic acid or deriv., of formula (IV), with (cyclo)aliphatic or araliphatic alcohols and nitrating agents, in the presence of an acid and with addn. of H2O, at >=35 degrees C. (I) are used e.g. in the prepn. of medicines, dyes and pesticides. High yields and purity are obtd.</p> |
