CA1050564A - Iodoethyl esters and process for the control of plant metabolism - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Iodoethyl esters of aromatic carboxylic acids are useful ingredients to influence plant metabolism. They may be used preferably for regulating fruit abscission. The esters disclosed in this invention corres-pond to the formula

Description

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The present invention rèlates ~o new iodoethyl esters of aromatic carboxilic acids, to a process for their preparation and to a process for the control of plant metabolism, with ~he aid of these esters.

The new iodoethyl esters correspond to the general formula I:
Rl R2 ~ (A)m-C00-CH2-CH2-I (I) The symbols in this formula have the following me~nings:
Rl represents hydrogen, lower alkyl, lower alkoxy, lower halogenalkyl, nitro, halogen, or the group CH3C00-, CF3C00-, benzoyl or m-chlorobenzyl~
R2 represents hydrogen, halogen, lower alkoxy, lower alkyl, R3 represents hydrogen, lower alkoxy, A represents the methylene group, the vinylene group (-CH=CH-) or lower oxyalkylene, and m represents the number 0 or 1, wlth the proviso that m is 1 if Rl, R2 and R3 are equal and represent hydrogen.
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- 3 s By lower alkyl is meant, according to the above definitions, straight-chain or branched radicals having 1 to 4 carbon atoms, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl 9 isobutyl, sec-butyl or tert-butyl. These lower alkyl radicals constitute also the alkyl moiety of an alkoxy radical. Trifluorornethyl is preferred as halogenalkyl;
but methyl or ethyl radicals mono- or polysubstituted by chlorine ar33d/or fluorine are also suitable. By halogen, denoted by Rl and/or R2, are meant, independently of each other, fluorine, chlorine9 bromine and/or iodine atoms.
The iodoethyl e~ters of aromatic carboxylic acids o~ formula I are produced by the reaction o~ a carboxylic acid derivative of formula 11:

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R2 ~ (A)m-CIDY (II) with a compound of formula III:

Z - CH2 - CH2 - I (III) ! 3 The sym3bols Rl, R2, R3, A and~m ih these formulae have the meanings given under formula ~, while Y and Z represent reactive radicals, and both stand ~or the hydroxyl group, or one of them represent~ a halogen atom and the other an optionally metalllsed hydroxyl group -~H or O-Me, wherein , .

Me denotes a mobile metal cation which can be split off~
e.g. an alkali metal cation, or the equivalen~ of an alkaline-earth metal cation.

It is advantageous if the reaction is performed iII
the presence of a solvent or diluent in~rt to the reactants; ~uitable solvents or diluents for this purpose are, e.g. hydrocarbons such as benzene, toluene or xylenesl halogenated hydrocarbons such as chlorobenzene, methylene chloride, e~hylene chloride, chloroorm, carbon te~rachloride, N,N-dialkylated amides such as dimethylformamide, also ethers and ethereal compounds such as dialkyl ether~ dioxane, t:etrahydro~uran, or, in the case where Y and Z each represent OH, the corresponding halogenated ethanol. If Y=Z=OH, or if one ;~
of the two symbols represents OH and the other halogen, then the process can be carried out in the presence of an anhydrous acid or base. Suitable acids are, e.g.
the following: hydrohalic acids, sulphuric acid, etc., and suitable bases are, e.g. inorganic bases such as alkali metal hydroxides and alkaline earth metal hydroxides or oxides; and organic bases such a~ tertiary amines.

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In the preferred embodiment of the process, a carboxylic acid halide, preferably the chloride or bromide, is reacted, as the carboxylic acid derivatives of formula Il, with 2-iodoethanol ~I-CH2-CH20H~ in the presence of a solvent, preferably benzene.

Iodoethyl esters of aromatic carboxylic acids of formula I
affect, in a varying manner, the growth of parts of pla.nts above and below the soil, the compounds have a low toxicity towards warm-blooded animals. The active substance cause no morpho~ogical changes or damage which would result in the wlthering of the plant. Their action ls different from that of a herbicidal active suhstance and Erom that of a fertiliser. The new compounds affect the germination power and the vegetative plant growlth, and promote blossom formation, fruit ripening and the formation of abscission layers.
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By virtue of their efectiveness, the iodoethyl esters oE
special importance are those corresponding to formula IV:

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Rl ~ (A)m-coo-cH2-cH2-I (IV) The symbols Rl~ A and I in this formula have the meanings defined under formula I.
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; Compounds particularly suitable for the promotlon of fruit and leaf abscission are compounds of formula V:
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R~' ~9 ( ClI)m Coo_C~12_C~12_1 (V) wherein ; Rll represents hydrogen, halogen, trifLuoromethyl, acetoxy or lower alkyl, and m represents the number 0 or 1.

; 2'-Fluoroethyl esters of aromatic carboxylic acids are known Erol~ the llterature as insecticidal and acarici~al active substances (cp. the German Ofenlegungsschrift 1,808,938). The compounds are phytotoxic and have a high toxicity towards warm-blooded animals.
The following example serves to illustrate the process according to the invention. The table following the example -contains further halogenethyl esters of aromatic carboxylic acLds of formula I7 which were obtained in the manner des~ribed in the said example. The temperatures are . j .
expressed in degrees Centigrade, and the pressure in Torr (1 Torr = 1 mm Hg).

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Exam~
An amount of 20 g of 3-acetoxybenzoyl chloride is dissolved in 200 ml of benzene, and 17.5 g of iodoethanol added. An addition is subsequently made dropwise at 15 - 25, with cooling and vigorous stirring, o 12 g of triethylamine; the organic phase is dried over ~odium sulphate, and the solvent distilled off. The oily residue is distilled in high vacuum. 3-Acetoxy-benzoic acid-(2'-iodoethyl)-ester passes over at 145-153/0.05 Torr.

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. ComPounds ¦ Physical I . _ .
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3-chlorobenzoic acid-(2'-iodoethyl)-ester B.P. 95/0.015 3-bromobenzoic acid-(2'-iodoethyl)-ester n20: 1.6050 3-tri~luoromethylbenzoic acid-(2'-iodoethyl)-ester B.P. 85/0.02 3-methylbenzoic acid-(2'-iodoethyl)-ester B.P. 96/0.01 3-methoxybenzoic acid-(2'-iodoethyl)-ester n23: 1.5730 3~5-dimethoxybenzoic acid-~2'-iodoethyl) ester n23: l.S317 3,4-dimethylbenzoic acid-(2'-iodoethyl)-ester n23: 1.5710

4~methoxybenæoic acid-(2'-iodoethyL)-es~er B.P. 138/0.03 3,4-dimethoxybenzoic aci.d-(2'-iodoethyl)-ester M P. 75-77 cinnamic acid-(2'-iodoethyl)-ester ~ nD : 1.6164 3~nitrobenzoic acid-(2'-iodoethyl)-ester B.P. 135/O OZ3 phenoxyacetic acid-(2'-iodoethyl)-ester B.P. 108/0.05 phenylacetic acid-(2'-iodoethyl)-ester B.P. 98/0.03 a-phenoxypropionic acid-(2'-iodoethyl)-ester B.P. 109/0.065 3-trifluoroacetoxybenzoic acid-(2'-iodoethyl)- oil ester 3-benzoylbenzoic acid-(2'-iodoethyl)-ester oil 3-(m-chlorobenzoyloxy)-benzoic acid-(2'-iodo- oil ethyl)-ester _ ~ _ -' ''"'''''-.

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' ,, , , , . . ' _ 9 The active substances of formula I promote, in particular, the formation of abscission layers between stalk and fruit stems. Consequently, fruit of every kind,su~h as, e.g. citrus fruits, stone fruit, berries, grape vines, pomaceous or oil fruits, can be picked without ~ny great applicatioll of force, either by hand or with machines developed for the purpose. Damage to the foliage and branches of the tree or bush usually occurring on gathering of the crop as a result of the violent shaking of the trees or bushes, or the tearing off of the fruit, is largely avoided.
The extent and the nature of the action are dependent on Lhe IIIOS~ dlverse Lactors, depel~dil)~ on Llle ~ariety of the pLant; they are dependent, in particular 9 on the applied concentration, and on the time of application with regard to the stage of development of the plant and of the fruit. Thus, for example, plants of which the fruit is processed or sold will be treated immediately after blossomlng, or at a suitable poin~ of time before ~he gathering of the crop. The active substances are preferably applied in the form of liquid agents to parts of plants above the soil, into the soil 3 or onto the surface of the soil. Applicatlon to parts of the plants above the soil is preferred, for whi~h application 2g solutlons or aqueous dispersions are best suited.

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The Lollowing tests show the action of the new compounds as abscission agents.

Example 2 Segments of bean leaves of the variety "Tempo" or their stems were immersed in solutions containing 10 and 20 ppm of active substance, respectively. In the case of each active substance, 8 leaf segnents or their stems were left for 5 days under controlled conditions in the active substance solution. The number of occurred abscissions was afterwards determined.
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Evaluation: 1 c no abscission 2 - abscission on 2 segments 3 = abscission on 4 segments 4 = abscisslon 011 6 segments = abscission oll 8 segments _ ._ Active substance 10 ppm 3,5-dimethoxybenzoic acid- 3 5 4 (2'-iodoethyl)-ester .
3-bromobenzoic acid-(2'-iodoethyl)- 4.5 5 ester cinnamic acid-(2'-iodoe~hyl)-ester 4.5 4~5 benzoic acid-(2'-iodoethyl)-ester 5 4 ! 3-chlorobenzoic acid-(2'-iodoethyl)- 5 5 ester 3-tri~luoromethylbenzoic acid- S 5 , (2'-iodoethyl)-ester 3-methylbenzoic acid-(2'-iodoethyl)- 5 4.5 3-acetoxybenzoic acid-(2'-iodoethyl)- _ 5 'I I I ~

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Example 3 On orange trees of the mentioned variety~ indivldual branches carrying at least 15-20 ripe oranges were sprayed with an active substance concentra~ion of 0.4%
and of 0.2%. The picking force required in the case of 10 identically treated oranges was measured 7 days a~ter applicat~on, with the aid of a spring balance, and the mean value of the 10 measurements calculated [W.C. Wilson and C.H. Hendershott~ Proc. ~m. Soc. Hort. Science 903 123-129 (1967)].
The active substances of formula I produced in this test the percentage reductions in picking force, compared with values obtained with untreated trees, li.sted in ~he following table:

Active substance Concen- Reduction in Variety tration in % picking force /0 phenylacetic acid-(2'-iodo- 0.4 95 15 ethyl)-ester O.Z 30 .benzoic acid-(2'-iodoethyl)- 0.4 S7 ester .. . .... _ . . ._ _ 3-chlorobenzoic acid-(2'-iodo-0.4 73 ethyl)-ester 0.2 60 3-bromobenzoic acid-(2'-iodo- 0.4 72 : ethyl)-ester 0.2 56 3-acetoxybenzoic acid-(2'- 0.4 95 lodoethyl)-ester 0.2 73 2 Varieties: 1 = Hamlin 2 ~ Temple .

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Herbicidal agents according to the invention are produced in a manner known per se by the intima-te mixing and grinding of active substances with suitable carriers, optionally with the addition of dispersing agents or solvents which are inert to the active substances. The active substances can be obtained and used in the following forms:
solid preparations: dusts, scattering agents, granulates, (coated granulates, impregnated granulates and homogeneous granulates);
water-dispersible concentrates of the active substance:
wettable powders, pastes, emulsions;
~, liquid preparations: solutions.
The solid preparations tdusts, scattering agents, granulates) are produced by the mixing of the active substances with solid carriers. Suitable carriers are, e.g. kaolin, talcum, bole, loess, chalk, limestone, ground limestone, attapulgite, dolomite, diatomaceous earth, precipitated silicic acid, alkaline-earth silicates, sodium and potassium aluminium silicates (feldspar and mica), calcium and magnesium sulphates, magnesium oxide, ground ; synthetic materials, fertilisers such as ammonium sulphate, ammonium phosphate, ammonium nitrate, urea, ground vegetable products such as bran, bark dust, sawdust, ground nutshells, cellulose powder, residues of plant extractions, active charcoal, etc., alone or in admixture with each other ~; - 12 -: . . , . :, "., , : . : ' ' , ' ' ~ ; ~ . , . :
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The particle size of the carriers is for dus-ts advantageously up to about 0.1 mm; for scattering agents from about 0.075 mm to 0.2 mm; and for granulates : 0.2 mm or coarser.
The concentrations of active substance in the solid preparation forms are from 0.5 to 80%.
To these mixtures may also be added additives stabilising the active substance, and/or non-ionic, anion-active, and cation-active substances, which, for example, improve the adhesiveness of the active substances on plants and . on parts of plants (adhesives and agglutinants), and/or ensure a better wettability (wetting agents) and dispersibility (dispersing agents). Suitable adhesives are, for example, the following: olein/lime mixture, :: cellulose derivatives (methyl cellulose, carboxymethyl cellulose), hydroxyethylene ~lycol ethers of monoalkyl and dialkyl phenols having 5 to 15 ethylene oxide radicals per molecule and 8 to 9 carbon atoms in the alkyl radical, ligninsulphonic acids, their alkali metal and alkaline-earth metal salts, polyethylene glycol ethers . fatty alcohol polyethylene glycol ethers having 5 to 20 ethylene oxide radicals per molecule and 8 to 18 carbon atoms in the fatty alcohol moiety, condensation products of ethylene oxide, propylene oxide, polyvinyl pyrrolidones, polyvinyl alcohols, condensation products of urea and formaldehyde, as well as latex products.
Water-dispersible concentrates of active substance, , ~ .

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i.e. wettable powders, pastes and emulsion concentrates, are agents which can be diluted with water to obtain any desired concentration. They consist of active substance, carrier, optionally additives which stabilise the active substance, surface-active substances, and anti-foam agents and, optionally, solvents. The concentration of active substance in these agents is 5 to 80%.
The wettable powders and the pastes are obtained i~ by the mixing and grinding of the active substances with dispersing agents and pulverulent carriers, in suitable devices, until homogeneity is attained. Suitable ~, carriers are, e.g. those previously mentioned in the case of solid preparations. It is advantageous in some cases to use mixtures of different carriers. As dispersing agents it is possible to use, e.g.: condensation products ., ~' . , .
of sulphonated naphthalene and sulphonated naphthalene ` derivatives with formaldehyde, condensation products of -~ naphthalene or of naphthalenesulphonic acids with phenol - and formaldehyde, as well as alkali, ammonium and alkaline-earth metal salts of ligninsulphonic acid, also alkylaryl sulphonates, alkali metal salts and alkaline-earth metal salts : .
of dibutyl naphthalenesulphonic acid, fatty alcohol sulphates such as salts of sulphated hexadecanols, heptadecanols, octadecanols, and salts of sulphated fatty alcohol glycol ether, the sodium salt of oleyl methyl tauride, ditertiary 'I acetylene glycols, dialkyl dilauryl ammonium chloride, and - fatty acid alkali-metal and alkaline-earth metal salts.
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Suitable anti-foam agents are, for example, silicones.
The active substances are so mixed, ground, sieved and strained with the above mentioned addi~ives that the solid constituent in the case of wettable powders has a particle size not exceeding 0.02 to 0.04 mm, and in the case of pastes not exceeding 0.03 ~n. For the preparation of emulsion concentrates and pastes, dispersing agents are used such as those mentioned in the preceding paragraphs, organlc solvents, and water. Suitable solvents are, e.g. the following: alcohols9 benzene, xylenes, toluene, dimethylsulphoxide, N,N-dialkylated amides, N-oxides : of amines~ particularly triallcylamines, and mineral oil fractions boiling in the range of 120 to 350. The solvents must be practically oclourless, non~phyto~oxic, inert to the active substances, and not readily infla~nable.
Furthermore, the agents according to the invention can be applied in the form of solutions. For this purpose the active substance (or several active substances) is (or ~re) dissolved in suitable organic solvents, mixtures of solvents, water, or mixtures of organic solvents with water. It is possible to use as organic solvents: aliphatic and aromatic hydrocarbons, their chlorinated derivatives, alkylnaphthalenes, mineral oils on ~heir o~n or in admix~ure with each other. The solutions are ta contain the active 8ubstances in a concentration of from 1 to 20%. These solutions can be applied witll the aid of a propellent gas (as spray), or by means of specinl sprayer~ (such as aerosol).
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Other biocidal active substances or agents may be added to the described agents according to the invention. For the supplementing or broadening of their sphere of action, the new agents can also contain, in addition to the stated com-pounds of the general formula I, e.g. insec:ticides, herbicides, fungicides, bactericides, fungistatics, bacteriostatics or nematocides. The agents according to the invention ` can also contain fertilisers, trace elements, etc.
Preparations of the new active substances are - 10 described in the following. The term 'parts' denotes ; parts by welght.

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Wettable powders The following constituents ar~ used for the preparation of a) a 5~%, b) a 25% and c) a 10% wettable powder:

a) 50 parts of 3,5-dimethoxybenzoic acid~(2'-iodoethyl)-S ester, parts o~ alkylarylsulphonate, parts of calcium lignin sulphonate, 1 part of Champagne chalk/ hydroxyethyl cellulose - mixture (1:1), parts of silicic acid, 14 parts of kaolin;
b) 25 parts of cinnamic acid-(2' iodoethyl)-ester, `~ S parts of the sodium salt of oleylmethyl tauride, 2.5 par~s o~ naph~halenesull~honlc acid/~ormaldehyde lS condensate, O.5 part of carboxymeth~yl cellulose, parts of neutral potassium~alulllinium-silicate, 62 parts of kaolin;

c) 10 parts of 3-acetoxybenæoic acid-(2'-iodoethyl)-ester, i 20 3 parts of a mixture of the sodium sal~s of saturated fatty alcohol sulphates ?
S parts of naphthalenesulphonic acid/formaldehyde condensate, 82 parts of kaolin.

The active substances are intimateLy mixed, in suitable mixers, with the additives; and the ~ixture is then ground by means of suitable mills and rollers. Wettable powders ~re obtained which can be diluted with watér to obtain 8~spensions of any desired concentratio~.

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~; a) 25 parts oE 3-bromobenzoic acid-(2'-iodoethyl)-ester~
S parts of a mixture of nonylphenolpolyoxyethylelle and calcium-dodecylbenzene sulphonate, 70 parts of xylene.

This concentrate can be dlluted with water to obtain .~
emulsions of suitable concentration. Such emulsions are suitable for the accelerated ripening oE fruits, and for the promotioll oE fruit and leaE abscission.
-- Itlstead of ~he active substances mentioned for the production of the wettable powders and the emulsion concentrate, :, it is also possible to use the other compounds embraced by formula I.

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Claims (12)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Compounds of the formula:

wherein R1 represents hydrogen, lower alkyl, lower alkoxy, lower halogenalkyl, nitro, halogen, CH3COO-, CF3COO-, benzoyl or m-chlorobenzoyl, R2 represents hydrogen, halogen, lower alkoxy, lower alkyl, R3 represents hydrogen, lower alkoxy, A represents the methylene group, the vinylene group (-CH=CH-) or lower oxyalkylene, and m represents the num-ber 0 or 1, with the proviso that m is 1 if R1, R2 and R3 are equal and represent hydrogen.

2. Compounds according to claim 1 of the formula:

wherein R'1 represents hydrogen, halogen, trifluoromethyl, acetoxy or lower alkyl, and m represents the number 1.

3. The compound phenylacetic acid-(2'-iodoethyl)-ester.

4. The compound 3-acetoxybenzoic acid-(2-iodoethy)-ester according to claim 1.

5. Process for the production of iodoethyl esters of aromatic carboxylic acids of the formula:

wherein R1, R2, R3, A and m have the meanings given in claim 1, with the proviso that m is 1 if R1, R2 and R3 are equal and represent hydrogen, the said process comprising the reaction of a carboxylic acid derivative of formula II:

(II) with a compound of formula III:

Z - CH2 - CH2 - I (III) wherein the symbols R1, R2, R3, A and m have the meanings given above, whilst Y and Z represent reactive radicals, and both represent the hydroxyl group, or one of them represents a halogen atom, and the other an optionally metallised hydroxyl group -OH or -O-Me, wherein Me represents a mobile metal cation which can be split off.

6. Process according to claim 5, wherein there is used, as a carboxylic acid derivative of formula II, a carboxylic acid halide; and this reacted with 2-iodoethanol in the presence of a solvent or diluent which is inert to the reactants.

7. Process according to claim 5, wherein Me represents an alkali metal cation or the equivalent of an alkaline-earth metal cation.

8. Process for the control of plant metabolism, the said process comprising the treatment of plants with halogenethyl esters of aromatic carboxylic acid of the formula wherein the symbols R1, R2, R3 A and m have the meanings given in claim 1, with the proviso that m is 1 if R1, R2 and R3 are equal and represent hydrogen.

9. Process according to claim 8, the said process comprising for the treatment of plants the use of compounds of the formula:

wherein R1, A, m and X have the meanings given in claim 1, with the proviso that m is one if R1 is hydrogen.

10. Process according to claim 9, the said process com-prising for the treatment plants the use of compounds of the formula:

wherein R'1 represents hydrogen, halogen, trifluoromethyl, acetoxy or lower alkyl, and m represents the number 0 or 1.

11. Process according to claim 8, the said process com-prising for the treatment of plants the use of the compound phenylacetic acid-(2'-iodoethyl)-ester.

12. Process according to claim 8, the said process compris-ing for the treatment of plants the use of the compound 3-acetoxybenzoic acid-(2'-iodoethyl) ester.