DD202706A5 - PROCESS FOR THE PREPARATION OF NEW PHENYLIMINOTHIADIAZOLINES - Google Patents

Abstract

The invention relates to a process for the preparation of phenyliminothiadiazolines of the general structural formula I, wherein R is hydrogen or one to four substituents selected from Cl, nitro, lower alkyl and lower alkoxy, R is high hydrogen, lower alkyl, lower alkoxyalkyl, lower Alkenyl, lower haloalkyl, or an agriculturally acceptable cation, R3 is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, lower haloalkyl or benzyl, and R4 is hydrogen or at least one substituent selected from 3,4-trimethylene, nitro, F , Cl, Br, CF, deep 3, lower dialkylamino, lower alkylcarbonyl, lower alkyl and lower alkoxy with the further condition that at least one ortho site is unsubstituted. These compounds are effective as growth regulators in various crops.

Description

Process for the preparation of new phenyliminothiadiazolines

Field of application of the invention

The present invention relates to a process for the preparation of novel phenyliminothiadiazolines which are effective as regulators of plant growth.

Characteristic of the known technical - ^^ ⁵

It is known that many chemical compounds act on plant growth. Frequently, a change in plant form, curvature and folding of leaves, inhibition of growth, leaf decay, stimulation of rooting in cuttings, and other effects have been observed. It is usually necessary to apply the growth-regulating compounds in a relatively small amount in order to obtain very clear growth-regulating effects. At higher levels, selective vegetation destruction is usually obtained, which is greater in some plant species than others. In fact, growth regulators have been used more as selective herbicides than for other purposes, because in many cases the growth regulating effects achieved by these substances have found no other practical application. Such compounds are described, for example, in Ulimann's Encyklopadie der technischen Chemie / 4th Edition, Volume 12, page 614.

Object of the invention

It is an object of the invention to enrich the state of the art with new, valuable growth regulators. _v

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Explanation of the essence of the invention

It is an object of the present invention to provide novel growth regulators based on phenyliminothiadiazolines which exhibit a number of useful effects which are different from plant species to plant species. For example, some of these compounds promote spotting (branching at the foot of the plant) in oats and certain other grasses and increase fruit set with simultaneous destruction of Digitaria sanguineis (Crabgrass).

Thus, according to the invention there is provided a process for the preparation of novel phenyliminothiadiazolines of general structural formula I.

(I)

provided, in which mean

R is hydrogen or one to four substituents selected Cl, nitro, lower alkyl and lower alkoxy,

2 "

R is hydrogen, lower alkyl, lower alkoxyalkyl, shunned

res alkenyl, lower haloalkyl, or an agriculturally acceptable cation, R is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, lower haloalkyl or benzyl, and

R is hydrogen or at least one substituent selected from 3,4-trimethylene, F, Cl, Br, CF ₃ , nitro, lower dialkylamino, lower alkylcarbonyl, lower alkyl and lower alkoxy with the further condition that at least one ortho site is unsubstituted,

which is characterized in that one has a compound

the general formula II

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(ID

O H

12 3 4

in which the radicals R, R, R and R have the abovementioned meaning, subjected to an acid-promoted ring closure dehydration reaction.

The terms "lower alkyl", "lower alkoxy", etc., as used above mean C, -C, -alkyl, etc.

Synthesis of laundry Turns're'gül'ät or en

The novel compounds according to the invention can be prepared by procedures based on the following illustrative syntheses. All temperatures are in degrees C.

The thiadiazoline compounds of the present invention are conveniently prepared by ring closure of a class of thiosemicarbazides which can be prepared by methods which are illustrated below by the specific procedures.

1. Synthesis of Methylhydrogeriphthalate

300 ml of methanol are added all at once to 148 g (1.00 mol) of phthalic anhydride and heated the resulting suspension under reflux conditions and stirring for 36 hours; during heating occurs solution. The solvent is removed and the product is recrystallized from a mixture of ethyl acetate and hexane to give 114.6 g of the title compound. (Lit .: Beilstein, '9 797; F 82.5 °, 84 °).

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2. Synthesis of methylphthalovol chloride

110, Og (0.611 mol) of methyl hydrogen phthalate and 77.4 g (0.650 mol) of thionyl chloride are mixed in 200 ml of chloroform, keeping the temperature below 30 °. After two hours of stirring at room temperature, the system is heated under reflux for five hours. The solvent is distilled off at reduced pressure; the crude product (120.9 is used without further purification (Ref: Beilstein, 9., 797, no constants).

3. Synthesis of 1- (2-carbomethoxybenzoyl) -2-methyl-4-phenyl-3-thiosemicarbazide

A solution of 45.3 g (0.25 mol) of 2-methyl-4-phenyl-3-thiosemicarbazide and 19.8 g (0.25 mol) of pyridine in 800 ml of 1,2-dimethoxyethane is stirred at room temperature and added 49.8 g (0.25 M methylphthaloyl chloride in 100 ml of 1,2-Dirnethoxyäthan added dropwise over a period of two hours

 The resulting reaction mixture is stirred for 16 hours at room temperature. At the end of this time, pour the contents of the flask into ice-water. The resulting solid is collected to give 73.3 g (85%); F 153.5-154 ° C.

The general procedure for the preparation of the invention, according to Phenyliminothiadiazoline consists in the acid-promoted ring closure dehydration reaction of a compound of general formula II

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Concentrated sulfuric acid, trifluoroacetic anhydride and thionyl chloride have been found to be effective under the acidic reagents, it appears that the results obtained are strongly dependent on the nature of the substituents R, R

4 and R depend.

So far as has been stated, the best general ring closure reaction involves the use of concentrated sulfuric acid in conjunction with chloroform as a diluent, as demonstrated by the following preparation of 5- (2'-carboxyphenyl) -2- (3'-fluorophenylimino) -3- methyl-l, 3,4-thiadiazole-4-one is illustrated.

In a 3-liter three-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser and dropping funnel, which is immersed in an ice bath, stirred a solution of 84.3 g (0.243 mol) of 1- (2'-carboxybenzoyl) -4- (3'-fluorophenyl) -2-methyl-3-thiosemicarbazide (F 155-7 ° C) in 1750 ml of chloroform, while slowly adding 404 g of concentrated sulfuric acid over a period of 30 minutes, the temperature below 25 ° C. holds. A clear two-phase solution is obtained after adding about half of the sulfuric acid. Stirring is continued for a further 2 hours at room temperature and the contents are carefully poured into a mixture of 800 ml of concentrated ammonium hydroxide and 2 kg of ice. The resulting two-phase system is stirred for 15 minutes and separated. The organic phase is discarded and the aqueous phase is stirred, cooled to 20 ° C and acidified with 370 ml of glacial acetic acid to a pH of 3, to obtain a solid precipitate. The slurry is stirred for 30 minutes at 10 ° C and filtered. The filter cake is rinsed with two 300 ml portions of cold water, then re-slurried in 750 ml of cold water, filtered and dried in air to give 65 g (81% yield) of a product having a melting point of 207-8 ° C receives.

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In the following, two specific procedures are given which include a laboratory method on a small scale:

Preparation of 2-phenylimino-3-methyl-5- (2'-carboxyphenyl) 1,3,4-thiadiazole-4-one

To 25 ml of H ₃ SO _{4 are} added 5 g (0.015 mol) of 1- (2'-carboxybenzoyl) -2-methyl-4-phenyl-3-thiosemicarbazide. After stirring for 30 minutes at room temperature, crushed egg is added. The resulting acidic solution is washed with ethyl acetate and then adjusted to pH 8 with concentrated NH ₄ OH. Collect the precipitate, wash it with water and dry it to obtain 1.0 g (F 223-225).

Preparation of 2-phenylimino-3-methyl-5- (2'-carbomethoxyphenyl) -1,3,4-thiadiazole-4-yne

Using the same conditions as described above, 5.0 g of 1- (2'-carbomethoxybenzoyl) 2-methyl-4-phenyl-3-thiosemicarbazide give 1.3 g of the desired product, mp 96-98 ° C.

Compounds prepared by the procedures described above are listed in Table I below. As can be seen from formula I.

1 4, the radicals R and R can be any free position on the

Occupy ring; this applies in particular to R in the compounds Nos. 3804 and 4016 given below.

TABLE I

Compounds of the formula I

Verb no. R ¹ R ² R ³ R ⁴ F ° C 2812 H H CH ₃ H 223-225 3107 H H CH ₃ 3-F 2O8-2O9 3291 H CH ₃ CH ₃ H 96-98 3356 H H CH ₃ 4-F 195-200 3357 H CH ₃ CH ₃ 4-F 60-61 3373 H CH ₃ CH ₃ 4-OCH ₃ oil 3498 Ci ₄ CH ₃ CH ₃ H 142-146 3499 Ci ₄ allyl CH ₃ H 90-93 3801 H H CH ₃ 2-CH ₃ 141-143 3802 H H Il 2-F 201-202

Remarks on usability

promotes the sprouting of oats

promotes the sprouting of oats

increased fruit set

promotes the sprouting of oats

increased fruit set

promotes sprouting

Oat CO CD O CD CD

verb

 No.

3804 H 384O H 3841 H 3842 H 3902 H

39O3 Η

TABLE I (continued)

CH.

CH, CH. CH-CH. H

3904 H H 39O5 H H 39O6 3-NO ₂ H 3908 H H 3961 H H 3965 H C ₂ H ₅ 4O16 H H

CH.

^R i F ° C 2 ^ -F 119-121 4-CF ₃ 87-88 4-NO ₂ 101-102 3-Cl oil 4-CH ₃ 73-75 3-NO ₂ 178-180 3-CF ₃ - 4-Cl 157-158 2-CH, - 3-Cl 147-148 2-Cl 194-195 H 194 ^ 195 2-CH _0-6-Cl 183-185 2,5-dimethyl 164-165 H 83-85 4-COCFU 197-198

Remarks on usability

increased fruit set and oat sprouting

increased fruit set increased fruit set increased fruit set increased fruit set

increased sprouting of oats

increased fruit set

increased sprouting of oats

"at Oat

increased fruit set

increased sprouting of oats

TABLE I (continued)

Verb no. R ¹ R ² 3 R ⁴ F ⁰ C Remarks on usability 4O58 H allyl 'CH ₃ H oil increased fruit set and shoot formation 4059 H H M 4-N (C ₂ H ₅ ) ₂ 175-177 increased sprouting 41O4 H H » 2,4-dichloro 168-17O Il 'Il 4114 H H Il 3-CH ₃ 160-162 increased fruit set and shoot formation 4171 H H 3-Br 164-165 increased sprouting. 4175 H H » 4-CF ₃ 211-213 Il 4177 H CH ₃ Il 4- (CH ₂ ) ₃ CH ₃ oil increased fruit set and shoot formation 4266 H CH ₃ Il ₃ -CH ₃ semisolid increased fruit set and oat sprouting 4271 H H Il 3,4-tri- 180-182 increased fruit set

JSJ CO CD

methylene

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- ίο -

Application of growth regulators , _ _τ

In the case of highly active compounds, phytotoxic effects frequently occur during application before emergence and after emergence. These effects can with. Help the following exemplary methods are demonstrated.

Application before emergence

About 6.35 cm (2.5 in.) Deep paper scrapers are filled with soil, sprayed with aqueous spray mixtures at a rate of 5.61 kg of active ingredient per hectare (5 lbs / acre) of the sprayed area, seeded with six types of plant seed and then covered with about 6.35 mm (1/4 in.) of earth. The spray mixtures are prepared by dissolving the correct amount of growth regulator compound in 15 ml of acetone, adding 4 ml of a solvent / emulsifier mixture consisting of 60% by weight of a commercial polyoxyethylated vegetable oil emulsifier (96% by weight of active ingredient, Emulphor EL). 719), 20% by weight of xylene and 20% by weight of deodorized kerosene, and then bringing the total volume to 60 ml by adding warm water. 21 days after sowing and treatment the plants are tested and the plant damage is assessed according to the following scheme:

Degree of effect;

0 = no effect

1 = slight effect, plants recovered

2 = moderate effect, damage 26 to 75 %

3 = serious effect, damage 76 to 99 %

of the foliage

4 = maximum effect (all plants enter).

Application after emergence

Several types of plants are grown in potting soil within

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- li -

Polystyrene dishes are grown and tomatoes are grown in 10.16 cm (4 in.) Pots in the greenhouse. Aqueous spray formulations are prepared and the cultured plants are sprayed at a spray volume of 561.3 Ltr / ha (60 gallons / acre) and application rate of 5.61 kg / ha (5 lbs / acre). The spray mixtures are produced in the above-mentioned way. For comparison, plants are further sprayed at 561.3 Ltr / ha with a spray mixture containing no growth regulator. In turn, plant damage is assessed according to the scheme outlined above, and the following growth regulatory effects are obtained in trials both before and after emergence:

effect Abbreviation m the tables Shaping effect on new growth F epinasty e growth reduction G ' necrosis - ^N no emergence K Chlorosis C

Table II below reports the observations of pre- and post-emergence herbicidal and growth regulator effects which result from the use of the growth regulators of the invention according to the above procedures.

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TABLE II

Effects of compounds on plant species

Verb. No. Effect on leakage Digitaria sanguinalie Celosia plumosa i Bvomus ! i Setaria italioa Raphanus sativus beta vulgaris Effect after Auslaui Medioago sativa ö SJ 'ti Hi * ü »ö Raphanus sativus beta vuIgaris Lycopersiawn esculentum K4 K3G3 F3G3 F3G3 G3F1 K4 Setaria italioa F3G2 F2 F2 F3G1 F3G2 2812 K4 F2G2 F3G3 F3G.3 F3G3 F3G3 F2G1 NLGI NLGI N1G2 N3G3 F2G3 3107 F3G3 F2G2 F3G3 F3G3 Fl FLGL N2G2 F3G2 Fl NlFl F3G3 F2 3291 - - - - - - FLGL - - - - - 3356 K4 K4 F3G3 F3G2 F3G2 F3G2 - F2G3 Fl. F2G2 F3G2 F4 3357 Fl 0 F2G1 F2G1 0 Fl. F2G1 F2G1 Fl N1F2 F2G3 F2G1 3373 0 0 0 0 0 0 FLGL Fl gl 0 F2G1 Fl 3498 K2G1 K4 F2G2 Fl K4 K4 F2 F3G3 F3G3 Fl F3G3 F3G3 0 F3G3 F3G3 Fl F3G2 F3G3 0 Nl F2G2 F2 N1G2 0 N1G2 GlFl 0 F2 N1G2 F2G2 F2 Fl F2 NlFl 3499 3801 3802 Fl Fl FlGl FlGl F3G3 K4 F2G2 F3G2 F2G1 F2G1 F2G2 F2G1 0 F2G3 Fl N1G2 Fl N4 F2 Fl F 2Gl Eq F3G1 F2 N1G2 N-2-F1-F3 3803 3804 0 F2G2 0 F2G1 Fl F3G2 0 F3G2 0 F3G2 0 F2G1 0 G2 0 F3G2 0 F2G1 0 Fl C2G2 F2G1 F2G2 Fl F3N1 3840 3841 F3G2 F2G1 K4 F3G2 F3G2 F2G2 0 C1G2 F3G1 FLGL FLGL F2G1 F2 3842 FLGL F2G2 K4 F3G2 F3G3 F3G2 Fl F3G3 F2G1 F2G2 F3G3 F2G2 3902 0 Fl Fl 0 0 F2 Fl F2G1 0 Fl F3G1 F2 3903 Fl F2 F3G3 F3G2 F3G2 F2G2 0 F3G3 Fl F2G2 F3G3 F3G1 3904 Fl F2 F3G2 FLGL F2G2 F2G2 Fl F3G2 FLGL FLGL F3G3 F2G1 3905 Fl

239 06 6 5

TABLE II (continued)

Effects of compounds on plant species

Verb.

No effect before leaking 3906 0 ö « 0 0} 9 r · ¹ 0 <0 0 to effect 0 • 2 -S after running out 0 to 0 to Il ^ S ro 3907 Fl • ti (Q F2G1 CO * r ^ "  w α F2G2 3 to F3G2 * ti F2G2 * X3 -i-i FLGL 3 W F3G2 CO - + J " 3908 0 <0 O 0 11 ' Q) 4i 0 Si 3 gl JL 0 ca α 0 0 J ^ 3961 F2G2 * »» 2 F3G2 CO * ti F3G3 "Si * fi F3G3 α cn α e F2G2 § CO FLGL S a Ä ti F2 "Ö vj Ο} ti · * ^ ta t-i S, C • ti O. gl Fl 3965 F2G2 Co Cl, F2G2 CQ'ti F3G2 α α F2G1 Q) 3 FLCL Fl fl ' α α F2C1 0) '3 4016 F2G2 FLGL F2 F3G3 cc w F2G2 CQ => +> α G2F2 0 Q) H-i F2G2 ft; co F2G1 ca =. Si w   4058 F3G3 F2G2 F3G3 F3G3 F3G2 Fl F2G1 F3G3 »C F2G2 F2G1 F2G1 4059 0 Fl K2 0 0 F2G2 CO * fi F2G1 <ΐ co FLGL FLGL N4 Fl 4104 FLGL G2F1 K4 F2G1 F3G1 0 G2 F3G2 Fl N4 N2 F2 4114 F3G3 F3G2 F3G3 F3G3 F3G2 N2G1 F3G2 F2G2 N4 N4 0 4171 Fl F3G3 F3G3 F2G1 F2G2 F2G2 F3G2 F2 F2G1 F3G1 4175 F3G3 F3G3 F3G2 F3G3 F3G3 F2G1 F2G2 F3G1 F2 F2G2 F3G3 4177 F2G2 F2G2 F3G3 F2G1 FLGL FLGL Fl FLGL F2 F2 FLGL F3 4266 F3G3 F2G2 F2 F3G3 F2G2 F3G2 F2G2 F3G3 F2G2 F2G1 F3G2 F3 4271 F3G3 F3G3 F3G1 F3G2 F3G2 Fl FLGL F3G1 F2G1 FLGL F2G1 F2 F3G3 F3G1 F3G2 N4 F2 F3G2 K4 F2 N4 F 2 F3G3 F2G1 F3G3 F3G3 F3G2 F3G3 F3G2 F3G2 F3G2 F3 F3G3 FLGL F2 F3G1 F3G3 F3G2 F3G3 F2 F3G2 F3G2 F3G1 F3

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The use of numerous growth regulator compounds can be demonstrated by the treatment of soybean (soybean max) increasing the number of seed pods and by the treatment of tomato plants (Lycppersicum esculentum) increasing the fruit set. In an exemplary experiment, soy max (Evans-Abart) and Lycopersicum esculentum (Tiny Tim-Abart) are grown in 10.16 cm (4 in.) Pots (one plant per pot). The pots are fertilized with greenhouse soil (2 parts good top soil), 1 1/2 parts building sand, 1 1/2 parts peat with 2,97 kg (5 lbs.) 12-12-6 fertilizer and 2 , 97 kg / m (5 lbs./cu.yd.) Of finely ground limestone). Aqueous spray preparations are prepared and the plants placed in the pots are sprayed at a spray volume of 374.2 ltr./ha (40 gallons / acre) and application levels of .1120, 280 and 70 g / ha (16, 4 and 1 oz./ acre). The spray mixtures are prepared by mar; Dissolve the right amount of growth regulator compound in 15% acetone, add 2 ml of a solvent / emulsifier mixture consisting of 60% by weight of a commercial polyoxyethylated vegetable oil emulsifier (96% by weight of active ingredient, Emulphor EL-719), 20% by weight. % Xylene and 20 wt .-% of deodorized kerosene, and then the total volume by adding a 0.156 wt .-% aqueous solution of a liquid nonionic dispersant (90 wt .-% active ingredient trimethylnonyl polyethylene glycol ether, Tergitol TMN-IO) to 80 ml brings. For each application amount, two specimens are sprayed. For purposes of comparison, plants are also sprayed at 374.2 ltr./ha (40 gallons / acre) with water. The number of seed pods and fruits as a percentage of the arithmetic mean of the numbers of untreated plants is determined within about 3 weeks after the spray treatment. The results are shown in Table II. The sharpness of growth

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regulatory effect on plants is assessed using a scale ranging from 0 to 10; the rating numbers are also shown in Table III.

TABLE III Soy max. , Growth regulating effect (2) two plant species Wax turnover control effect (2) CD Number of patties (1) % compared to untreated plants 5.5 2.0 0 Lycopersicum esculentum 7,5 4,5 1 O Growth regulation effects 174 ^a 143 109 6.5 2.0 1 Fruit number (1) % compared to untreated plants 6 4 1 cn 138 ^a 112 93 3.5 1.0 0 ^400b 255 182 5.5 1.5 0 cn Connection no. Application rate g / ha (oz / acre) 143 115 110 7,5 5 4 136 ^C 245 218 4.5 2 0 υπ I Ι-ι 2812 1120 (16) 280 (4) 70 (1) 140 129 136 7 1.5 1 136 ^C 27 109 7 4.5 O C 1 31O7 112O (16) 280 (4) 7O (1) 105 136 1 99 700 900 200 3291 1120 (16) 280 (4) 70 (1) HOO 8OO 3801 1120 (16) 280 (4) 70 (1) 38O2 112O (16) 28O (4) m ( ι ^

112O 28O 7O (16) (4) (D 119 87 94 5 2 0,5 112O 280 7O (16) (4) (D 143 115 87 8 5.5 3.5 1120 280 7O (16) (4) (D 84 101 105 1.5 0.5 0 1120 28O 70 (16) (4) (D 119 108 1Ο5 7.5 5.5 1.5 112O 28O 7O (16) (4) (D 133 108 119 7.5 3.5 0.5 112Ο 28Ο 7Ο (16) (4) (D 138 121 125. 1.5 0 0 112Ο 280 7Ο (16) (4) (D 114 114 97 5.5 3 1.5

TABLE III (continued) CO CD CD

(1) control

(2) Greenhouse rating on scale from 0 (no effect) to IO (complete kill)

a smaller pods b malformed fruit c stimulated growth

800 3, 5 700 3 400 0 5 900 6 5 700 3 800 1 200 O 200 O 100 O 7OO 5 800 4 500 1 7OO 6 800 2 8 00. 1, 5 214 3, 5 182 2 118 1 175 4, 5 225 2 113 1

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The information given in the tables given here make it possible for a person skilled in the art to make a selection of the growth regulator compounds according to the invention and to get a certain idea of the application amounts depending on the desired effect. It can be seen, for example, that complete killings of certain plant species occur frequently at such high application rates as 5.61 to 11.22 kg / ha <(5 to 10 lbs./acre), while favorable effects on live plants at application levels of 1.12 kg / ha (1 lb./acre) or less.

The growth regulator compounds are usually applied in combination with inert carriers or diluents, such as in aqueous spray preparations, granules and dusts, in accordance with conventional practice. An aqueous spray preparation is usually prepared by mixing a wettable powder or an emulsifiable concentrate of a growth regulator with a relatively large amount of water to form a dispersion.

Wettable powders are intimate, finely divided mixtures of growth regulator compounds, inert solid supports and surfactants. The inert solid support is usually selected from the group consisting of attapulgite clays, kaolin clays, montmorillonite clays, diatomaceous earths, finely divided silica and purified silicates. Effective surfactants, which have wetting and dispersing penetration, are usually present in wettable powder formulations in proportions of from 0.5 to about 10 -.% Present. Surfactants commonly used for this purpose include the sulfonated lignins, naphthalenesulfonates and condensed ones

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Naphthalenesulfonates, alkylbenzenesulfonates, alkyl sulfates and nonionic surfactants such as ethylene oxide condensation products with alkylphenols.

Emulsifiable concentrates of the growth regulator compounds in each case comprise a solution of the growth regulator compound in a liquid carrier which is a mixture of a water-immiscible solvent and surfactants such as emulsifiers. Useful solvents include aromatic hydrocarbons such as xylenes, alkylnaphthalenes, petroleum distillates, terpene solvents, etherealcohols and organic ester solvents. Suitable emulsifiers, dispersants and wetting agents can be selected from the same classes of products as are used to formulate wettable powders.

In general, the growth regulator formulations advantageously contain from 0.1 to 95 wt -.% Of a compound of formula (I) and 0.1 to 75 wt .-% of a carrier · or surfactant. However, the direct application to plant seeds prior to planting may in some cases be made by mixing the powdered solid growth regulator with the seed to obtain a substantially uniform coating which is very thin and only 1 or 2% by weight (or less), based on the weight of the seed. In most cases, however, a non-phytotoxic solvent, such as methanol, is used as a carrier to facilitate uniform distribution of the growth regulator on the surface of the seed.

If a compound is to be applied to the soil, as is the case in a pre-emergence application, granular preparations are sometimes more convenient than spraying.

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Preparations. A typical granule comprises the growth regulator compound dispersed in an inert carrier, e.g. in coarsely ground clay or clay which has been converted to granules by treating a rolling bed of the powdered material with a small amount of liquid in a granulating drum. In the usual process for the preparation of granules, a solution of the active ingredient is sprayed onto the grains while they are agitated in a suitable mixing device, after which the grains are dried with constant air flow.

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Preferred compounds include those of general formula I in which the radicals have the meaning given below:

R ¹ TABLE IV R ² R ³ R ⁴ No. H H methyl H 1. , H H methyl 3-fluoro Second H methyl methyl H Third H H methyl 4-fluoro 4th H methyl methyl 4-fluoro 5th   H methyl methyl 4-methoxy ⁶ '' Λ ' 3,4,5,6-tetrachloro .Methyl methyl H 7.; 3,4,5,6-tetrachloro allyl methyl H. δ. H H methyl 2-methyl 9th H H methyl 2-fluoro 10th H methyl methyl 2-fluoro 11th H methyl methyl trifluoromethyl 12. " H methyl methyl 4-nitro 13th H methyl methyl 3-chloro 14th H methyl methyl   4-methyl 15th H H methyl 3-nitro 16th H H methyl 4-chloro-3-trifluoromethyl- 17th H H Methyl '" 3-chloro-2-methyl 18th H · H methyl 2-chloro 19th 3-nitro H methyl H 20th H . H methyl 2,5-dimethyl 21st H ethyl methyl H 22nd   H H methyl acetyl 23rd H allyl methyl H 24th H H methyl 4-diethylamino 25th H H methyl 2,4-dichloro 26th H H methyl 3-methyl 27th H H methyl 3-bromo 28th

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No. R ¹ R ² R ³ R ⁴ 29th H H methyl 4-Trif.luormeth 30th H methyl methyl 4-butyl 31st H Methyl. methyl 3-methyl 32nd H H methyl 3,4-Trimethyle

The use of the plant growth regulating compounds of the present invention, including the destruction of undesired vegetation, is to affect plants by applying an effective amount of a compound of the above class of compound to either the seed, the soil or directly to the plants.

Claims (4)

R is hydrogen or one to four substituents selected from Cl, nitro, lower alkyl and lower alkoxy, R is hydrogen, lower alkyl, lower alkoxyalkyl, lower alkenyl, lower alkyl, or an agriculturally acceptable cation, R is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, lower haloalkyl or benzyl, and R is hydrogen or at least one substituent selected from 3,4-trimethylene, nitro, F, Cl, Br, CF ₃ , lower dialkylamino, lower alkylcarbonyl, lower alkyl and lower alkoxy with the further condition that at least one ortho site is unsubstituted, characterized in that a compound of general formula II 239066 5 -Μ 1 2 3 4 in which the radicals R, R, R and R have the meaning given above, subjected to an acid-promoted ring closure dehydration reaction. 2. The method according to item 1, characterized in that one carries out the ring closure dehydration reaction in the presence of sulfuric acid, trifluoroacetic anhydride or thionyl chloride as acid promoter. 3. The method according to item 1 and 2, characterized in that one carries out the ring closure dehydration reaction in the presence of sulfuric acid as a promoter and in the presence of chloroform as non-reactive diluent. 4. The method according to item 1 to 4, characterized in that one carries out the ring closure dehydration reaction at room temperature.