JPS5883652A - 4-fluoro-5-nitrophenol derivative and its preparation - Google Patents

Abstract

NEW MATERIAL:The 4-fluoro-5-nitrophenol derivative of formulaI(X is Cl or Br). EXAMPLE:2-Chloro-4-fluoro-5-nitrophenol. USE:Useful as a synthetic intermediate of a compound having strong herbicidal activity against weeds without affecting the important crops such as corn, wheat, rice plant, soybean, cotton, etc.[e.g. 2-(4-chloro-2-fluoro-5-isopropoxyphenyl)-5, 6,7,8-tetrahydrophthalimide]. PROCESS:The compound of formulaIcan be prepared by (1) converting the halophenol of formula II to an alkali metal salt with an aqueous solution of sodium hydroxide, etc., (2) reacting the salt with methyl chloroformate in an aqueous solvent preferably at 0-10 deg.C, (3) nitrating the resultant compound of formula III with concentrated sulfuric acid-concentrated nitric acid mixture, and (4) hydrolyzing the reaction product with an alkaline aqueous solution of e.g. sodium hydroxide.

Description

Detailed Description of the Invention The present invention provides a 4-fluoro w-5-nide a phenol haze conductor represented by the general formula (I[) ν O C, in which I represents a chlorine atom or a bromine atom] and its It concerns the manufacturing method.

The compound of the present invention represented by the general formula (on the side of the general formula) is useful as a synthetic intermediate for a compound represented by the following general formula (f) having a herbicidal action.

In the formula C, R represents an alkyl group, an alkenyl group, or an alkynyl group.The compound represented by the general formula (■) has little phytotoxicity with respect to important effects on corn, wheat, rice, soybean, wax, etc. It also has a strong herbicidal power against weeds, and typical compounds include 2-(4-chloro-2-fluoro-6-ituproI-kyrephenyl)-8,
@, 1,8-tetrahydro-7-talimide (compound 1 in IF5 table), 2-(4-chloro-2゛-fluoro-5-
Propargyl oxyphenylt! , 6.7.8-tetrahydroimide (compound 2 in Table 111), IC4
- Kuroro! -FluoW-6-allylokire7enyltho11.6.7.8-tetrahydro7thaluid (mu1
There are compounds 8) in the table, and their herbicidal activities are as exemplified below.

Table 1 In the following test examples as simple rhymes, all evaluations of efficacy against cultivated plants and weeds were expressed as evaluation values using integers from O to b, in accordance with the criteria described below. At the time of survey: At point 11, measure the fresh weight of the above-ground parts of the plants that remained withered, and calculate the ratio when compared to the fresh weight of the plants in the untreated pot area. Cultivated plants and weeds were evaluated for chemical damage and herbicidal efficacy using numbers from 0 to 6 based on the criteria shown in the table below. An evaluation value of 0 or 1 for cultivated plants or an evaluation value of 6 or 4 for weeds is generally considered to be an appropriate cultivated plant preservation effect or weed control effect.

In addition, only in the case of the paddy rice test, the evaluation value is calculated based on the dry weight of the plant.

Reference example Corn weeding test (stem and foliage treatment) Freshly harvested 8
6tm, - width 26em, height 1051 plastic tray asking for land destruction, corn, crocodile, sunflower, Ebisugusa, Malva morning glory, Noharagarare,
After sowing chickweed and foxtail grass and growing them in a greenhouse for two weeks, the height was 50 am, the width was 110 Ga, and the height was 4.
Two of these trays were arranged in a 0 m frame, and a predetermined amount of each chemical was applied to the entire surface of the frame from above the plants using a small shaking sprayer. After spraying the chemicals, the plants were grown in a greenhouse for 8 more days, and then each plant was examined for chemical damage or herbicidal efficacy. The results are shown in Table 112. An emulsion was used as the processing agent and was emulsified in water to which a spreading agent was added. The large red color of the plant when treated with chemicals varies depending on the species, but the ink on the plant leaves is t-s.
In the first season, the plant height was 2~Rotm-S! Compounds useful as herbicides represented by the general formula (1) of Ato9dine are:
It can be synthesized using the halophenol represented by the general formula (II) as a starting material and via the compound of the present invention represented by the general formula (III) according to the following reaction route.

(a) (Otori)
(■) (V) (I) In formula 1, x# and a are as described above. ) That is, the phenol derivative of the general formula (V) can be used under iIs such as dimethylformamide, dimethylsulfonate, etc., alkali metal carbonates such as potassium carbonate, alkali metal hydroxides such as potassium hydroxide, and alkalis such as water bulking sodium. In the presence of a base such as a metal hydroxide or an alkali metal alkoxide such as sodium alkoxide, preferably in the presence of an alkali metal carbonate, with an alkyl halide, alkynylpalite, or alkynylpalite at o-too°C, preferably 7°C.
M- of general formula (I) by reacting at 0 to 90°C
, is converted to enyltetrahydro-7-talimide derivative.

The heptanoyl derivative of the general formula (V) can be prepared by combining the aminophenol derivative of the general formula QV) and 8.4,5.6'-tetrahydro heptanol acid anhydride in an inert solvent such as acetic acid. 6
It can be produced by refluxing for a period of time, generally 2 to 4 hours. The aminophenol derivative of general formula (y) can be obtained by reducing the nitrophenol derivative of general formula (Ill).

Catalytic reduction is a common means of reducing nitro groups in aromatic fields;
Any method is possible, such as reduction using iron powder, reduction using sodium sulfide, reduction using sulfurized NaBH4, etc.
The aminophenol derivative of the general formula (■) obtained by this catalytic reduction, which is preferably reduced with hydrogen at normal pressure, can be converted to 31.4,5.6-tetrahydro7-threshold without any purification. Can be used in reactions with acid anhydrides. The nitrophenol derivative of general formula (Otori) is represented by general formula (II)
It can be produced by selectively nitrating halophenol according to the following reaction formula.

In the formula r, X is as described above. ) 8*7 of general formula (n)! Nord is G, C, Fin
Geru, J, A11. Ch@lk 800.8
194 (191S9)-Q is publicly known.

A halophenol of the general formula (VI ) can be obtained.Furthermore, by nitration using concentrated sulfuric acid and concentrated nitric acid at room temperature, a nitrobenzene derivative of general formula (■) can be obtained.This nitrobenzene haze conductor can be hydroxylated. It is converted into a nitrophenol flange conductor of the general formula (I[) by hydrolysis using an aqueous alkaline solution such as sodium, preferably at 40 to 80°C.

This selective nitration can be performed using many chloroformate esters to obtain almost the same results.

Confirmed example 1 Synthesis of 2-chloro-4-fluoro-5-nitrophenol - Add to the sodium hydroxide aqueous solution prepared from
Methyl chloroformate 119.2F was added dropwise below. The resulting crystals were washed with water one by one to obtain 184.8f of crude methyl (2-ria-4-fluorophenyl) formate. mp69-71C Methyl (2-chloro-4-fluorophenyl)formate 184.8f was suspended in concentrated sulfuric acid 50-1 and warm soap (concentrated sulfuric acid 50-1 concentrated sulfuric acid 50-1) was added to the suspension.
) was added dropwise at around 80°C and stirred at that temperature for an additional hour. The reaction solution was poured into ice, and the resulting crystals were repeatedly washed with water to give 14jlf of methyl (2-chloro-4-fluoro-
6-nitrophenyl) formate was obtained. mp68~5
The mixture was filtered at 6 DEG C., the solution was acidified with concentrated hydrochloric acid, and the resulting crystals were washed individually with water to obtain 76.8 f of 2-chloro-4-fluoro-6-nitrophenol.

mp108~107℃! MMR (CDC/i, Da-DM80) βpp
m7.25 (IH, l, J=10i1z), 7, 1$
4 (tn, a, J-4ag) Example 2 Synthesis of 2-bromo-4-fluoro-6-nitrophenol 2-bromo-4-fluorophenol 28f was added to an aqueous sodium hydroxide solution (7t of sodium hydroxide was added to 100m (dissolved in water), methyl chloroformate was added dropwise at below 10°C, and the resulting crystals were separated, washed with water, and
-Methyl-bromo-4-fluorophenyl formate was obtained. 1
1 m) 80.7℃ Suspend this in concentrated sulfuric acid of Higashi 8-, add 18 dl of concentrated sulfuric acid, *@
A mixed acid of acid 18 was added dropwise at around 80°C. Stir for a further 80 minutes, pour over ice and wash the formed crystals thoroughly with water.
8-Bromo-4-fluoro-5- as yellow crystals of 8F
0mp @ 39.5-64. tC
The mixture was refluxed for 8 hours with 6.2 f sodium hydroxide and 100 g water. Separate the insoluble matter, acidify the liquid with hydrochloric acid,
The resulting crystals are separated from each other and washed with water to form 26f 2-bromo-4.
-Fluoro-5-biblindness

Claims (1)

[Claims] (1) Selective nitration of herrophenol represented by the general formula (wherein, X represents a chlorine atom or a bromine atom) A method for producing a 44-fluoro-6-nito c1 phenol tsuba conductor represented by the general formula (wherein, X is as described above).