| 摘要 |
<p>Compounds of the formula: I ¢wherein R1 and R2 may be the same or different and each is selected from the group consisting of hydrogen, an alkyl group and, together, an alkylene chain; and R3 is an alkyl group; R4 is selected from the group consisting of an alkyl group and, with R3 and the N atom, a heterocyclic ring! or derivatives thereof are prepared by reacting benzoquinone with an enamine R1R2C=CH-NR3R4 in the presence of a compound of formula R1R2CHCHO. The product contains a lower proportion of hydroquinone impurity and finds use in the preparation of herbicides.</p> |
