Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Patent
1992-05-14
1993-11-23
Killos, Paul J.
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
560 9, 560 11, 560 15, 560 37, 560 60, C07C 6976, C07C31706, C07C22928
Patent
active
052646092
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a new process for the preparation of certain propenoic acid derivatives.
PRIOR ART
Alkyl 2-aryl-3-alkoxy-2-propenoate derivatives have been disclosed as having pesticidal activity. Compounds of this type are disclosed for example in EPs 178826, 203606, 203608, 206523, 229974, 226917, 242070, 242081, 243012, 243014, 251082, 256667, 260794, 260832, 267734, 270252, 273572, 274825, 278595, 291196, 299694, 307101, 307103, 310954, 312221, 312243, 329011 and 336211. Numerous processes and intermediates for their preparation have been disclosed in these and other publications. In EP 310954 for example certain 3-hydroxy intermediates are disclosed and in GB 2202843, certain 3,3-dimethoxy intermediates are diclosed.
DESCRIPTION OF THE INVENTION
We have now found an improved process for the manufacture of alkyl 2-aryl-3-alkoxy-2-propenoate derivatives. Many intermediates are also novel.
Thus according to one aspect of the invention there is provided a process for the preparation of a compound of formula I ##STR5## in which Ar is aryl and R.sup.1 and R.sup.2 are alkyl, in which a compound of formula II ##STR6## where Z is a disubstituted amino group,
a) is reacted with an alcohol, R.sup.2 OH, preferably under acidic conditions, to give a compound of formula III ##STR7##
which is then dealkanolated, or
b) is hydrolysed under acid conditions, to give a compound of formula IV ##STR8## which is then alkylated.
The compound of formula II can be obtained by reacting a compound of formula V on the desired nature of the group Z, but is generally a dialkylformamide dialkylacetal, preferably, dimethylformamide dimethylacetal. This reaction is generally carried out at a temperature between 100.degree. and 180.degree. C., suitably at reflux. If necessary a solvent, e.g. toluene, may be used. A catalyst such as pyridinium tosylate may be present.
The compounds of formula V are either known or can be obtained in known manner.
Z is preferably dialkylamino, especially a dimethylamino group, but the term could also include ring closed amino groups such as morpholino or piperidino and amino substituted by groups such as substituted alkyl, alkenyl, alkynyl, cycloalkyl or aryl.
The reaction with the alcohol in step a) is generally carried out in the presence of a mineral acid, such as hydrochloric or sulphuric acid, at a temperature of e.g. 25.degree. to 150.degree. C., and suitably at reflux.
The dealkanolation reaction in step a) is generally carried out using an alkali metal hydrogen sulphate or an intimate mixture of sulphuric acid and an alkali metal sulphate.
The hydrolysis reaction in step b) is generally carried out in the presence of an acidic ion-exchange resin. Examples of such resins are those composed of nuclear sulphonic acid exchange groups attached to a styrenedivinylbenzene copolymer. The proportion of crosslinking is preferably within the range 2 to 16%. Such resins are sold under various trade names, e.g. Amberlite IR-116 to Amberlite IR-124 or the Dowex-50W series. Macroreticular (macroporous) resins of this type are particularly suitable and are sold under various trade names, e.g. Dowex MSC-1 or Amberlyst 15. It is desirable that this reaction is carried out at moderate temperatures, e.g. 0.degree. to 50.degree. C., and suitably at room temperature.
The alkylation in step b) is suitably carried out in conventional manner, e.g. using an alkyl halide or sulphate, preferably under basic conditions, e.g. in the presence of a metal (especially sodium) hydride.
Since it is generally desired that the compound of formula I is obtained in the E-form, the product is generally heated under acidic conditions to convert any Z-isomer into E-isomer.
The compounds of formula I obtained by the process of the invention are disclosed as having pesticidal and especially fungicidal activity in for example the patents listed in the prior art
Ar is preferably an optionally substituted phenyl group or a heteroaryl group and is preferably
a) a phenyl group of formula ##STR9## in which
Cornell Clive L.
Richards Ian C.
Conrad Joseph M.
Killos Paul J.
Schering Agrochemicals Limited
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