2,3-DIHYDRO BENZOFURANYL-5-ESTERS, PARTICULARLY ESTERS OF ALKYL SULFONIC ACIDS WHICH POSSESS PHYSIOLOGICAL ACTIVITY, WHICH ARE PARTICULARLY USEFUL AS HERBICIDES AND ALSO AS PLANT GROWTH REGULANTS. 8 Claims, No Drawings
The invention provides a method of combating rhizomatous and stoloniferous weeds by the application to a locus either infested or liable to infestation therewith an effective amount of 2,3-dihydro-3,3-dimethylbenzofuran-5-yl ethanesulphonate.
Compounds of formula ##STR1## wherein R.sup.1 represents a branched chain alkyl group of at least 4 carbon atoms or a cycloalkyl group of at least 4 carbon atoms; R.sup.2 and R.sup.3 are the same or different and each represents a hydrogen atom or an alkyl group of 1-6 carbon atoms; R.sup.4, r.sup.6 and R.sup.7 are the same or different and each represent a hydrogen or halogen atom or an alkyl or alkoxy group of 1-4 carbon atoms; and R.sup.5 represents an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group, Are outstanding herbicides and plant growth regulants.
New and valuable 4-benzofuranyl esters having a good herbicidal action, herbicides containing these compounds as active ingredients, a process for controlling the growth of unwanted plants with these compounds, and a process for their manufacture.
A plant physiologically active compound is of formula ##EQU1## characterised in that R.sup.1, R.sup.2 and R.sup.3 are the same or different and each represents hydrogen or alkyl, or R.sup.1 and R.sup.2 together or R.sup.2 and R.sup.3 together form an alkylene chain; R.sup.4 represents a halogen atom; R.sup.5 represents alkyl, substituted alkyl, aryl or substituted aryl; and R.sup.6, r.sup.7 and R.sup.8 are the same or different and each represents hydrogen, alkyl, halogen, cyano, alkanoyl or alkoxy.
Compounds of the formula: ##STR1## wherein R.sub.1 and R.sub.2 are the same or different and each is selected from the group consisting of hydrogen, an alkyl group and together, an alkylene chain; M is alkyl of 1 to 6 carbon atoms; and R.sub.6 is selected from the group consisting of hydrogen and R.sub.5 SO.sub.2 -- wherein R.sub.5 is alkyl of 1 to 6 carbon atoms, are prepared by a procedure in which the key step is reacting benzoquinone with an enamine R.sub.1 R.sub.2 C.dbd.CHNR.sub.d 3 R.sub.4 in the presence of a compound of the formula R.sub.1 R.sub.2 CHCHO. The product contains a lower proportion of hydroquinone impurity and is useful as a herbicide.
