CA1068709A - Pyridine-n-oxide compounds - Google Patents

Abstract

Abstract of the disclosure Compounds of the formula I
wherein one of R1 and/or R3 are substituted carbamoyl and the other is preferably hydrogen or methyl, R2 is a variety of substituents among which is hydrogen and acetyl, and R3 and R4 preferably form together a saturated or unsaturated C4-chain which may be substituted, are valuable aphicides.

Description

~06870g This invention relates to compounds of the formula I

R4 ~ R2 R5 N Rl o in which one of the radicals Rl or R3 represents a radical or the formula II

-O-C-N \ II

and the other one is hydrogen, (Cl-C3)alkyl or phenyl; R2 is hydrogen or acetyl,R4 is hydrogen, and R5 is hydrogen or (Cl-C4)alkyl, or R4 and R5 together re-present tetramethylene or a group of the formula -CH-CH-CH=CH-, these radicals optionally being substituted by halogen, ~Cl-C4)alkyl, ~Cl-C3)alkoxy, CF3 or phenoxy.
Preferably one of the radicals Rl and R3 represents dimethylamino-carbonyl and the other one is methyl or hydrogen.
This invention also relates to a process for the manufacture of compounds of formula I, which comprises oxidizing compounds of formula III

R4 ~ R2 III

in known manner.
Suitable oxidizing agents are, besides hydrogen peroxide, peracids, for example performic acid, peracetic acid, halogenated peracetic acids such as pertrifluoroacetic acid, perpropionic acid, perlactic acid, monopermaleic acid, monopersuccinic acid, perbenzoic acid, substituted perbenzoic acids

-2-q~

1~;)68709 such as 3-chloroperbenzoic acid, monoperphthalic acid, diperphthalic acid, percamphoric acid, or mixtures thereof. Performic acid, peracetic acid, monpermaleic acid, perbenzoic acid, monoperphthalic acid, 3-chloroperbenzoic acid and hydrogen peroxide are preferred.
If a~ailable, the aforesaid peracids can be used as such, or they can be prepared i~ situ, for example by reacting an excess of the basic car-boxylic acid or the anhydride thereof with hydrogen peroxide, the excess of the carboxylic acid or the anhydride serving as solvent.
Suitable solvents for hydrogen peroxide or the peracid are also those which are inert under the reaction conditions, such as water, ether, benzene, or halogenated hydrocarbons, for example chloroform, dichloroethane, and chlorobenzene The oxidation agent is generally used in an amount of from one to several molar equivalents, calculated on the starting compound Qf formula III. Higher amounts may also be used without disadvantage. The reaction proceeds smoothly at a temperature in the range of from -5~C to 150C. In general, the reaction is carried out at room temperature or under ~ooling.
The starting compound$ of farmula III are a~tained, for example, by~reacting correspondingly substituted 2- or 4-hydroxypyridines or quino-lines with a) corresponding carbamoyl halides or b~ with phosgene or chloro-formic acid esters with subsequent further reaction with a suitable secondary amine (cf. German Offenlegungsschrift P 23 61 438). The compounds according to the invention have a considerably higher melting point than the starting compounds of formula III and, therefore, can be readily separated therefrom, for example by recrystallization.
The compounds of formula I have a very good selectivè insecticidal activity, especially against aphids, and furthermore possess excellent system-ic properties. They exert their activity not only via the plant foliage but also via the root system. Therefore, aphids living hidden in~ide of plant 10687C~9 parts can be combated with good results. The compounds are likewise active against aphids which have become resistant to phosphoric acid esters.
Examples of aphids which can be combated successfully by the new campounds are Brevico~yne brassicae, Myzaphis rosarium, Aphis schneideri;
Eriosomatidae such as Eriosoma lanigerum; gall-forming aphids such as Pemphi~s sEec. as well as Myzodes persicae.
On the other hand, useful coleopters (such as lady bugs) J butter-1ies, orthopterae, dipterae, hymenopterae ~such as ichneumon 1ies), and predator~ mites feeding on insect pests are not affected even by high concentrations of the active ingredients~ The action on aquatic organisms is insignificant, the compounds having an action on fish only at high concen-trations.
The compounds of the present invention or the preparations contain-ing them may be applied in widely varied manners. They may be applied to the f~cllage and/or affected parts of it or, on the other hand, to the earth surrounding the plant.
Marketable compositions containing these compounds may be in the form of dusting formulations, powders or granules, wherein the active ingre-dient is present in admixture with solid extenders or carrier materials such as inert substances in powder or granular form. Generally, these composi-tions contain from 3 - 75% of these compounds. Suitable solid extenders or carrier materials are, for example, kaolin, bentonite, kieselguhr, dolomite, calcium carbonate, talcum, ground magnosia ~chalk?, fuller's earther, plaster, diatomaceous or agrillaceous earth. The CQmpositions may also be used as wettable powders containing-in addition to the active ingredient -known wetting agents andlor dispersing agents and optionally fillers and/or emulsifiers as further additives.
The compositions may further be used as liquid preparations such as --emulsion concentrates for spray liquors which normally contain the active ingredient together with one or several wetting agents, dispersion auxiliariesJ
or emulsifiers. For liquid preparation organic solvents may also be used.
Before application these emulsion concentrates are normally further diluted to concentrations down to 0.0005%.
The wettable dispersion and emulsify.ing agents may be of either one of the cationic, anionic, or non-ionic type.
The compounds of formula I may also be used as active ingredients in fumigants.
The following examples illustrate the invention.
EXAMPLES OF PREPARATION
Example 1:
2,6-Dimethyl-4-dimethylaminocarbonyloxy-pyridine-1 oxide OCON(CH3)2 ,~
o 1~.4 g (0.1 mole) of 2,6-dimethyl-4-dimethylaminocarbonyloxy-pyridine were dissolved in 150 ml of anhydrous chloroform free of alcohol and, while externally cooling with icewater and stirring, a solution of 25 g of

3-chloroperbenzoic acid ~70% strength) in 400 ml of chloroform was added dropwise.
After standing for 4 days at room temperature the chloroformic solution was shaken three times with 100 ml each of 2N soda solution and one time with distilled water and the aqueous extracts were discarded.
After drying of the chloroform phase over calcium chloride the chloroform was distilled off in vacuo at a bath temperature not exceeding 40C. ~he oily residue was crystallized from n-hexane yielding 13.2 g of a 10687C~9 product that still contained a small proportion of initial carbamate as ascer-tained b~ thin layer chromatography. The crude product was therefore re-crystallized twice from acetonitrile, yielding 5.9 g of a product which was substantially free of initial carbamate and melted at 189 - 190C ( the initial carbamate melted at 75 - 76C).
Example 2:
2-Methyl-4-dimethylaminocarbonyloxy-quinoline-1 oxide OCON(CH3)2 o 23 g (0.1 mole) of 2-methyl-4-dimethylaminocarbonyloxyquinoline were dissolved in 150 ml of dry chloroform free of alcohol and, while stirring and externally cooling with ice-water, 25 g 3-chloroperbenzoic acid ~7q% strength) dissolved in 400 ml chloroform were added dropwise.
After standing for 5 days at room temperature the chloroformic solution was shaken three times with 100 ml each of 2N soda solution and one time with 100 ml distilled water and the aqueous phases were discarded.
After drying over calcium chloride the chloroform was distilled of in a rotary evaporator. The crystalline residue which contained traces of initial carbamate was recrystallized from n-hexane/toluene with addition of a small amount of charcoal. 14.5 g of pure crystalline N-oxide melting at 152 C uere obtained (the initial carbamate is liquid at room temperature) Example 3:
2-Methyl-4-dimethylaminocarbonyloxy-5,6,7~8-tetrahydroquinoline-10687~9 l oxide OCON (CH3)2 ~0 \CH3 Under the conditions specified in Examples l and 2, 18 g (0.077mole) of 2-methyl-4-dimethyl-5,6,7,8-tetrahydroquinoline were oxidized in chloroform with 13.5 g 3-chloroperbenzoic acid (70% strength).
After removal of chloroform and recrystallization of the residue from n-hexane/benzene, 9.5 g of pure N-oxide melting at 197 - 198C
were obtained. (Melting point of initial carbamate 89C).
Example 4:
10 2-Meth~1-6-methoxy-4-dimethylaminocarbonyloxyquinoline-l oxide OCON (CH3)2 o 33.5 g (0.13 mole) of 2-methyl-6-methoxy-4-dimethylaminocarbony-loxyquinoline were dissolved in 280 ml glacial acetic acid and 30 ml of a 30% solution of hydrogen peroxide were added dropwise at about 0 to 8C.
After standing for 40 days at room temperature, 2N soda solution was added with external cooling until the reaction mixture had a pH of 5.
T~e separating crystals of the oxidation product were filtered off, washed with cold water and dried. 37 g of crude product were obtained which were freed from traces of initial carbamate by recrystallization, first from 20 ethanol, then from acetonitrile and finally from benzene. 8 g of pure N-oxide 106t~709 melting at 172 - 173C were finally obtained (melting point of initial carbamate 80 - 81C).
EXAMPLE 5:
2-Methyl-6-methoxy-4-dimethylaminocarbonyloxy-5,6,7,8-tetra-hydroquinoline-l oxide OCON(CH3)2 C~13~

O

25.5 g ~0.096 mole) of 2-methyl-6-methoxy-4-dimethylaminocarbonyloxy-5,6,7,8-tetrahydroquinoline were dissolved in 75 ml dry, alcohol-free chloroform and oxidized as described in Examples 1 and 2 with a solution of 30 g 3-chloro-perbenzoic acid in 230 ml chloroform.
After working up under the conditions specified in the foregoin~
examples an oily crude product ~31 g) was obtained from which 13 g of crystal-line product were obtained by crystallization with n-hexane. The product was recrystallized from n-hexane/benzene yielding 6 g of uniform N-oxide melting at 121 - 122C, Imelting point of the starting compound 49 - 51C).
The following N-oxides of pyridine and quinoline carbamates wer~
prepared in analogous manner:
Example structural formulamelting point 6 OCON(CH3)2141 - 142C
C6HSO ~

~ CH3 ' ` 1068 7(~9 Ex~ple structural ormula melting ~oint 7 OCON tCH3) 2 Ol CON (CH3)2 8 ~ 1 CH 164 - 166C

g OCON ~CH3) 2 165 - 167C
CH3 ~ CH3 OCON (CH3) 2 ` HCF2~

OCON ~CH3) 2 OC6H3 o Example structural formula melting point OCON(CH3)2 12 ~ ~ N 1 CH3 ~CH~ o OCON~CH3)2 13 ~ ~ CH 165 14 ~ N OCON(CH3)2 130-131C

Jo/
ocoN~cH3)2 ~ CH3 123 - 124C

Q
O-C-N(CH3)2 16 ~ C6H5 140 - 150C

17 ~ 115 - 122C
N ~ -C-N(CH3)2 O O

_ 10 -106~709 EXAMPLE structural formula melting point ¢~
0-C-N(CH3)2 O-C-N(CH3)2 I
19 Br ~ ~ 195 N ~ CH (decomposi~ion) C.

o EXAMPLES OF FORMULATION
Example A
A ~ettable po~der readily dispersable in water is obtained by grinding 12 parts by weight of 2-methyl-4-dimethylaminocarbonyloxyquinoline-1 oxide as active ingredient with 3 parts by ~eight of calcium-magnesium-aluminum silicate and mixing the product obtained with 45 parts by weight of a mixture prepared from 10 parts by weight of cellulose pitch (potassium salt of lignin-sulfonic acid) 49 parts by weight of silica (quartz and kaolinite) 8 parts by weight of colloidal silicic acid 7 parts by ~eight of polypropylene oxide/colloidal silicic acid 1 : 1 l part by weight of sodiumoleylmethyl taurate.
Example B

An emulsifiable concentrate consists of . 1068709 1.5 parts by weight of 2-methyl-4-dimethylaminocarbonyloxy-5,6,7,8-tetrahydroquinoline-l oxide 6.5 parts by weight of cyclohexane as solvent and 2.0 parts by weight of ethoxylated nonyl phenol as emulsifier BIOLOGICAL EXAMPLES
Example I
Potted horse beans ~Vicia faba~ infested ~ith a stabilized popu-lation of bean aphids ~Doralis fabae) were sprayed to the drip off with an aqueous dilution of the emulsion concentrate containing the compound of Example 2 as active ingredient in decreasing concentrations. 3 days later the percentage of killed aphids was determined by caun*ing the surviving and killed animals.
The result is indicated in the following Table I in comparison with two compounds of similar structure and comparable efficiency. The compounds of Example 1 to 6, 8, 10, and 13 to 19 had practically the same efficiency, Table I
Formula % active compound per % mortality liter spray liquor OCON(CH3)2 0 000375 100 0.00019 75 H 0.000095 -from Netherlands 0.006 100 Spec. 6,606,695 N~ 0.0006 20 OCON(CH3)2 1068~709 Table I

Formula % active compound per % mortality liter spray liquor Isolan 0.005 100 CH(CH3)2 0.0025 96 ~ 0.0012 60 (CH3)2-N-c-o ~ ~ 0.0006 20 .
Example II
The root systems of potted horse beans infested with a population of bean aphids ~Doralis fabae) were wrapped in sheets and a glass funnel was inserted into the center of each system. By means of the glass funnels aqueous dilutions of an emulsion concentrate of the compound of Example 2 in decreasing concentration were uniformly distributed in the root area of the test plants. After 8 days the percentage of mortality was determined by counting the dead and surviving aphids on the plants.
mg of active compound 0.5 0.25 0.125 0.06 per root system % mortality 100 100 92 45 Practically the same results were obtained with the other compounds listed in Example I.
Example III
Populations of Myzodes persicae on potted paprika plants (Capsicum anuum) were sprayed to the drip off with aqueous dilutions of an emulsion concentrate containing the compound of ~xample 2 in decreasing concentrations.
2 days later the mortality rate was determined by counting the surviving and the dead animals.

~068709 % active substance per 0.003 0.0015 0.00075 0.000375 liter spray liquor % mortality 100 100 92 50 The results Qbtained ~ith the other comp~unds listed in Example 1 ~ere practically identical.

Claims (8)

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

1. Compounds of the formula I

in which one of the radicals R1 or R3 represents a radical of the formula II

II

and the other one is hydrogen, (C1-C3)alkyl or phenyl; R2 is hydrogen or ace-tyl, R4 is hydrogen, and R5 is hydrogen or (C1-C4)alkyl, or R4 and R5 together represent tetramethylene or a group of the formula -CH=CH-CH=CH-, these radi-cals optionally being substituted by halogen, (C1-C4)alkyl, (C1-C3)alkoxy, CF3 or phenoxy.

2. A process for the manufacture of a compound of formula I which com-prises oxidizing a compound of formula III

III

3. Method of combatting noxious aphids which comprises treating the infested plants with an effective amount of a compound as claimed in claim 1.

4. The compound of claim 1 which is

5. The compound of claim 1 which is

6. The compound of claim 1 which is

7. The compound of claim 1 which is

8. The compound of claim 1 which is