SI7911704A8 - Process for preparing 2-chloro-6-nitroanilines - Google Patents

Description

The invention relates to the preparation of novel 2-chloro-6-nitroanilines that affect plant growth.

A technical problem

There was a need for a technologically advanced process to prepare new 2-chloro-6-nitroanilines that affect plant growth, in good yields and in satisfactory purity.

The state of the art

The compounds defined by the formula (I) below are novel, and the process for their preparation has not yet been described.

Description of solution to a technical problem with implementation examples

According to the invention, we propose a process for preparing new ones

2-Chloro-6-nitroanilines of general formula

in which they stand

R for hydrogen, fluorine, chlorine, bromine, trifluoromethyl, methyl or methoxy and

X for oxygen or sulfur.

The residue R may be in position 2, 3 or 4.

Some nitro groups are known to have substituted diphenylether herbicidal properties (cf. K.H. Buchel, Pflanzenschutz und Schadlingsbekampfung, Georg Thieme Verlag, Stuttgart 1977 »p. 166).

As we have now found, the amino group substituted compounds of formula I are distinguished by their excellent herbicidal effect against many grasses and other weeds.

In addition, novel compounds can also be used selectively in many crops of useful plants.

New compounds are prepared:

by metabolizing phenols or thiophenols of the formula

wherein R and X have the above meaning, in the presence of an acid-binding agent, or - preferably - in the form of the corresponding phenolate or. of thiophenolate, in particular sodium or potassium salts, with 2,3-dichloro-6-nitroaniline of the formula

at a temperature between room temperature and about 120 ° C, preferably between 50 ° and 100 ° C.

The solvent used is the reaction medium, inert to the reaction conditions, in particular acetonitrile or dimethylformamide, e.g. methylethylketone, dimethylsulfoxide, N-methylpyrrolidone.

The starting materials of formulas II and III are obtained in the usual manner. For the preparation of anilines III, which are partially novel, 2,3,4-trichloronitrobenzene can be reacted with 2 moles of NH 4 in a suitable solvent. In general, aniline II can be used without further purification for further metabolism. However, it is sometimes convenient to purify compound III by distillation, recrystallization or column chromatography. The use of purified aniline of Formula III generally leads to better overall yields and produces a direct enough pure Pure End Product.

The starting materials can be obtained by mode 1).

The new compounds of Formula I are also valuable intermediates for plant protection products and medicines because they can be converted in various ways based on amine and nitro groups.

For use as herbicides, compounds of Formula I may in a known manner be converted by conventional excipients and / or carriers into conventional preparations, e.g. into emulsion concentrates or suspension powders, in which the content of the active substance is between about 10 and 95% by weight. % and adjust the concentration of the active substance suitable for application with water. However, we can also prepare preparations that are used undiluted, e.g. powders or granules. For these, the content of the active substance is between 0.2 and 20% by weight, preferably between 0.5 and 5% by weight. %.

Preparation of starting materials of formula III.

EXAMPLE

2,3-Dichloro-6-nitro-N-isobutylaniline

75.5 g of 2,3,4-trichloronitrobenzene and 48 g of isobutylamine are dissolved in 200 ml of toluene and maintained at room temperature for 3 days. An additional 5 g of isobutylamine are then added and heated to 60 ° C for 4 hours. The toluene solution is shaken off with water, dried and evaporated. 86 g (98% of theory) of the title compound are obtained as a brownish oil.

B

-6 H

CH, <^ 5 ^C A

CHj

C ^ H? iC ^ ^n_ ^ 4 ^ 9 “” ^ 3 ^ 7 (CH ₃ ) ₂ CHCH. H _c C _o CHCHhoch ₂ ch ₂

H

H

H c ₂ h ₅ ch ₃

H

H

H n-C ^

H

H

H (ch ₂ ) ₅ (ch ₂ ) ₄

- (ch ₂ ) ₂ -n- (ch ₂ ) ₂ CH ₃

- (ch ₂ ) ₂ -o- (ch ₂ ) ₂ H ⁿ “ ^C 6 ^H 13 nC ^ H ^

0CH ₂ = CH-CH ₂ -

Tal.ali 20 Solvent Reaction volume D peratuia Cas 166 ° C DMSO 50 ° 24 ^hours 60 ° C DMSO 10 ° 3 hours 51 ° C DMSO ST 4 hours 1,564 th most common DMSO s 5 hours 1,590 th most common DMF ST 5 hours 1,627 th most common DMSO ST 3 hours 1,615 th most common DMSO ST 26 hours 1,613 th most common DMSO ST 2 days 1,557 th most common without 00 o o 9 hours 1,605 th most common toluene ST 3 days 1,603 th most common toluene 80 ° 8 hours 94-5 ° C DMSO ST 16 hours 73-4 ° C dioxane ST 3 days 1,600 toluene ST 2 days 93-4 ° C dioxane 100 ° 10 hours 107-8 ° C dioxane 100 ° 10 hours 1,591 th most common i toluene ST 2 days 1,593 th most common i toluols 1 ST 2 days 1,615 th most common toluene ST 3 days 1,636 th most common toluene ST 3 days

DMSO: dimethylsulfoxide ST: room temperature

DMF: dimethylformamide

EXAMPLE 1

a) 2,5-Dichloro-6-nitroaniline

4-55 E 2,5 "4-tricks of oily trobenzoyl (2 moles) are dissolved in 2 l of dimethylsulfoxide and filled into an autoclave with volume 5 1. Add 200 ml of liquid ammonia (8 moles). After closing the autoclave, heat the nozzle with stirring or shaking to 50 ° C and maintain at that temperature for 24 hours.

After cooling and aeration of the autoclave, pour the resulting solution with the extracted NH 4 Cl into 8 l of water. The recovered product is filtered off with suction, washed with water and dried overnight at 50 ° C. 400 g (96.5% of theory) of a yellow crystalline product are obtained which melt at 161 to 164 ° C. The product is pure enough for further metabolism. However, it can also be purified by recrystallization, e.g. from methylisobutyl ketone; the gain is 77% of theory, m.p. 166 to 167 ° C.

b) 2-chloro-5-phenoxy-6-nitroaniline h 1) from crude 2,5-dichloro-6-nitroaniline

A solution of 105.5 g of 2,5-dichloro-6-nitroaniline (0.5 mol) and 65 "8 g of sodium phenolate (0.55 mol) in 1000 ml of acetonitrile was refluxed for 5 hours and then evaporated. Dissolve the residue in 750 ml of chloroform and shake the solution twice with 200 ml of water each. After drying the chloroform solution, it was evaporated. The residue, 150 g of brown oil, is hot dissolved

- 8 in about 700 ml of isopropanol and cool the solution with stirring. The title compound was precipitated and aspirated. 98 g of yellow crystals (74% of theory) were obtained from m.p. 85 ° C.

The NMR spectrum confirms the structure.

b 2) From purified 2,5-dichloro-6-nitroaniline _; Dissolve 15.5 g of purified 2,3-dichloro-6-nitroaniline in 75 ml of dimethylsulfoxide, add 7.8 g of phenol and 11.5 g of ground potassium carbonate and stir for 8 hours at 50 ° C. The product is then acidified with ice, the product is precipitated with ice water, sucked off and dried. 19.5 g of the final product are obtained (98% yield with respect to the 2,3-dichloro-6-nitroaniline used). Yellow crystals, m.p. 80 to 82 ° C.

EXAMPLE 2

2-Chloro-5-phenoxy-6-nitroaniline

A solution of 911 g (4 moles) of 2,3,4-trichloronitrobenzene was dissolved in 4 l of dimethylsulfoxide and 400 ml of liquid ammonia was added to a 10 l autoclave. The autoclave is closed and maintained at 50 ° C for 24 hours, with a pressure of 5.3 bar.

After cooling of the nozzle and ventilation of the pressure vessel, the precipitate is removed and mixed with 400 g of 40% (wt.%) Sodium hydroxide solution in 15 l vessels. In doing so, the ammonia we leak is escaping. Then 416 g of phenol (4.4 moles) were added to the solution, heated to

50 ° C and. 440 g of 40% (wt.%) sodium hydroxide are added dropwise and the nozzle is stirred for 7 hours at 50 to 60 ° C. To complete the reaction, 41 g of phenol and 44 g of 4-0% (wt.%) Sodium hydroxide were added again and maintained at 60 ° C for a further 3 hours. Then allow the nozzle to cool, acidify it with 100 ml of ice, then precipitate the product with ice water when shaken. The yellow-brown, solid crude product is filtered off with suction, washed with water and dried. The crude product (980 g, mp 70 to 78 ° C) was recrystallized from 2.5 l of isopropanol. Yield: 800 g (75.5% of theory) of a tan solid. Tal. 81.5 to 83.5 ° C ·

EXAMPLE 3

2-Chloro-3-phenylthio-6-nitro-N-methylaniline

To a solution of 4-4 g (0.02 mol) of 2,3-dichloro-6-nitroN-methylaniline dissolved in 50 ml of acetonitrile was added

2.9 g of sodium thiophenolate. The nozzle was heated at reflux for half an hour, then evaporated and the residue was taken up with chloroform and water. The chloroform layer is separated, dried and evaporated. 6 g of a brown oil are obtained which crystallizes with isopropanol.

4 g of yellow crystals, m.p. 79 ° C (67.5% of theory) Analysis: C H N Cl S Calc .: 52,7% 5.72% 9Λ7% 12.05% 10.9% Found: 52,75% 5.75% 9.55% 12,00% 10,82%

EXAMPLE 4

2-Chloro-3- (3-chlorophenoxy) -6-nitro-trifluoroacetanilide g 2-chloro-3- (3-chlorophenoxy) -6-nitroaniline was partially dissolved in 500 ml of toluene. With stirring, 70 6 trifluoro acetanhydride were added dropwise over 15 minutes. The attachment was stirred overnight.

The solvent is then distilled off, the residue is dissolved in 3θ0 ml of ether and the product is precipitated by the addition of gasoline by scraping, suction and drying. 101 g of a pale white-yellowish colored, crystalline solid, m.p. 99 to 101 ° C (85% of theory).

EXAMPLE 5

1,1-dimethyl-3- (2-chloro-5-phenoxy-6-nitrophenyl) -formamidine

7.9 g of 2-chloro-3-phenoxy-6-nitroaniline was heated with 10 ml of dimethylformamide and 10 ml of dimethylformamidimethylacetal for 8 hours at 100-110 ° C. The nozzle was then evaporated in vacuo at 90 ° C. A reddish, tough mass is obtained which solidifies at about 0 ° C. The analysis confirms the above formula.

Analysis: 0 H N Cl Calc .: 56,54% 4,41% 13,14% 11.09 Found: 56,54% 4.39% 13,17% 11.09

EXAMPLE 6

2-chloro-3- (4-chlorophenoxy) -6-nitro-N-2-chloroethylaniline

4.5 g of 2-chloro-3- (4-chlorophenoxy) -6-nitro-N-2-hydroxy-ethylaniline were dissolved in 40 ml of toluene and 2.9 g of PCl2 was added, resulting in spontaneous heating and gas evolution.

After 30 minutes, shake off the nozzle with water and Nabicarbonate solution and evaporate. 3 »6 g of a yellowish oil are obtained (76% of theory).

EXAMPLE 7

2-Chloro-3-phenylthio-6-nitroaniline dO3.5 g of 2,3-dichloro-6-nitroaniline (0.5 mol) and 72.5 g of sodium thiophenolate (0.55 mol) are dissolved in 800 ml of acetonitrile and 5 ur is heated at reflux. We process the attachment in accordance with example 1 bd). D08 g of a crystalline colored crystalline product (77% of theory), m.p. 144 to d46 ° C.

EXAMPLE 8

2-chloro-3- (3-chlorophenoxy) -6-nitroaniline dO3.5 g of 2,3-dichloro-6-nitroaniline (0.5 mol) and

82.8 g of sodium 3-chlorophenolate was heated in 500 ml of dimethylformamide for one hour at dOO ° C. After evaporation of the solution, the residue is taken up in chloroform, washed with water and the dried chloroform solution is evaporated.

The oily residue was warmly dissolved in about 700 ml of isopropanol. On cooling, the title compound crystallizes. 90 g of a circularly colored, crystalline solid are obtained from the soil. 101 to 102 ° C.

EXAMPLE 9

2-chloro-3- (4-fluorophenoxy) -6-nitro-N-ethylaniline

23.5 6 (0.1 µol) of N-ethyl-2,3-dichloro-6 ~ nitroaniline was dissolved in 150 ml of dimethyl sulfoxide in a 250 ml three-necked flask.

After the addition of 12.3 6 (0.11 moles) of 4-fluorophenol and 15.2 g (0.11 moles) of potassium carbonate, the product was stirred for 5 hours at 80 ° C. The product was slowly precipitated from the cooled solution by slow addition of ice water and recrystallized from isopropanol after suction to give 17 g of a color-coated crystalline product, m.p.

to 70 ° C (54.7% of theory).

Analysis: C H H Gl F Calc .: 50,90% 2.85% 9.92% 12.55 % 6.72% Found: 51,17% 3,01% 9.92% 12,35 % 6.54%. Properly the above by example we get also . next

compounds

R X A B l f i— ' • 4-C1 0 H I H 108 4-CHj 0 H I H 97-98 4-0CH ₃ '0 H H i 113-115 3-CH ₃ 0 H iH I 112-114 4-C1 S H jH 136-138 4-F 0 H and ^H 111-113 2-C1 0 H 'H 85-86 4-Nr 0 H H 118 3-CF ₃ 0 r H h < 92-93 3-F 0 H H l 58-60 2-F 0 H H 104-105 4-C1 0 cocf ₃ ^H ! 135-137 4-CHj 0 cocf ₃ H i 155 H 0 CH ₃ H! i 76 4-C1 0 cb ₃ , I H i I 75-77 3-Cl 0 CH ₃ H i oil 4 — CH 2 O 0 ch ₃ h: 100-101 4-F 0 ch ₃ H ^: 103 H 0 ^C 2 ^H 5 H oil

HFs (a) (b)

R X A ------------------ RF values B [° cj (a) (b) 4-F 0 ^C A H 71-72 4-C1 0 ^C A H 72-74 • 4-CHj 0 ^C A H 51-52 H s ^C 2 ^H 5 H oil 0.6 0 45 3-CH ₃ 0 ^C A H oil 0.61 . 0.445 3-C1 0 ^C A H oil 0.60 0.48 4-CH ^ C 0 ^C 2 ^H 5 H 47-48 1 4-Nr 0 ^C 2 ^H 5 H 57-59 2-C1 0 ^C A H oil 0.58 1 0.045 3-CF ₅ 0 ^C A H oil 0.60 0.49 H 0 n-C ^ Hy H oil 0.615 0.47 H 0 -ch (ch ₃ ) ₂ H oil 0.61 0.45 H 0 ch ₃ ch ₃ 69-72 t 4-F 0 CH ₃ ch ₃ 43-44 H 0 ^C A ^C A oil 4-C1 0 n-C ^ H? H oil 0.63 0.525 4-C1 0 -ch (ch ₃ ) ₂ » oil 0.63 0.50 H 0 n-C ^ Hg H oil 0.625 0.50 4-F 0 n-C ^ H? H oil 0.61 0.48 4-F 0 ch (ch ₃ ) ₂ H oil 0.62 0.46 4-CH ^ 0 n-C ^ H? H oil 0.64 0.47 H 0 n-C ^ H? nC ^ H oil 4-F 0 nC ₄ Hg oil 0.63 0,505 th most common 4-C1 0 nC ₄ Hg H oil 0.64 0.55 4-CHj 0 nC ₄ Hg H oil 0.64 0,495 th most common

St. R X A B Tal. [° c] RF value (a) (b) 54 4-CH ^ O 0 η-Ο ^ Ηγ H oil 0.59 0.29 55 4-ch ₃ o 0 -CH (CH ₂ ) ₂ H oil 0.57 0.28 56 4-ch ₃ o 0 nC ₄ Hg H oil 0,555 th most common 0.32 57 4-Nr 0 η-Ο ^ Ηγ H oil 0.59 0.52 58 4-Nr 0 n-C ^ Hg H oil 0.61 0,555 th most common 59 3-CF ₃ 0 ^nC 3H7 H oil 0.59 0.53 60 H 0 ch ₂ ch (ch ₅ ) ₂ H oil 0.60 0.51 61 H 0 -CHC ^ H oil 0.61 0.50 ch ₃ 62 4-F 0 ch ₂ ch (ch ₃ ) ₂ H oil 0.60 0.525 63 4-F 0 H oil 0.62 0,515 th most common 64 4-CI 0 CH ₂ CH (CH ₂ ) ₂ H oil 0.63 0.56 65 H 0 C ^ OH H oil 0.445 0.01 66 H S ⁿ “ ^C 3 ^ 7 H oil 0.62 0.49 67 H S -CH (CH ₂ ) ₂ H 56-57 68 H s n-C ^ Hg H oil 0.63 0.52 69 H s ch ₂ ch (ch ₃ ) ₂ H oil 0.78 0.52 70 H 0 -C ₂ H ₄ OH H oil 0.44 0.01 71 4-CH ^ O 0 ch ₂ ch (ch ₅ ) ₂ ^H oil 0.58 0.35 72 H 0 - (ch ₂ ) ₄ - 106-107 73 H 0 - (CH-) e- 98-99 74 H 0 - (ch ₂ ) ₂ -n- (ch ₂ ) ₂ - CH, 99-101 75 H 0 109-110 76 H s ch ₃ H 128-130 77 4-F 0 ^nC 6 ^H 13 H oil 0.63 0.57

No. R X A B Tal. [° cl RF value (a) (h) .. 78 H 0 ^nC 5 ^H ll H oil 0.62 0.54 79 4-C1 0 - (CH ₂ ) ₅ - 105 80 4-F 0 ^nC 5 ^H ll H oil 0.62 0.56 81 » 0 / - \ - <H> \ _ / H . oil 0.61 0.52 82 H s -CH ₂ -CH = CH ₂ H oil 0.72 0.48

Claims (2)

A process for the preparation of 2-chloro-6-nitroanilines of the formula in which they stand R for hydrogen, fluorine, chlorine, bromine, iodine, trifluoromethyl, methyl, methoxyl and nitro, X for oxygen or sulfur, characterized in that the phenol or thiophenol of the formula, optionally in the form of a salt, in particular an alkali salt, or in the presence of an acid-binding agent, is reacted with dichloronitroaniline of formula no ₂ (III) 18 at a temperature between room temperature and 120 ° C, in an inert solvent. A process according to claim 1, characterized in that acetonitrile or dimethylformamide is used as the inert solvent.