JPS61140572A - 4-substituted nitrobenzoxazine derivative and preparation thereof - Google Patents

Abstract

NEW MATERIAL:The 4-substituted nirobenzoxazine derivative of formula I (R<1> is alkyl, alkenyl, alkynyl, alkoxyalkyl or alkoxyalkoxyalkyl; R<2> is H or CH3). EXAMPLE:7-Fluoro-6-nitro-4-propargyl-2H-1,4-benzoxazin-3(4H)-one. USE:Intermediate of herbicide. PREPARATION:The compound of formula I can be prepared by reacting the compound of formula II with the compound of formula R<1>-X (X is Cl, Br ir I). The compound of formula I can be converted to the compound of formula III useful as a herbicide by reacting with 3,4,5,6-tetrahydrophthalic anhydride after reduction. The starting compound of formula II can be produced by reducing and cyclizing the compound of formula IV (R<3> is lower alkyl) with iron powder, and selectively nitrating the resultant compound of formula V with a mixture of sulfuric acid and nitric acid.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on the general formula [wherein R represents an alkyl group, an alkenyl group, an alkynyl group, an alkoxyalkyl group, or an alkoxyalkoxyalkyl group, and R2 represents a hydrogen atom or a methyl group] . The present invention relates to a 4-substituted nitrobenzoxazine derivative (hereinafter referred to as the compound of the present invention) represented by the following formula and a method for producing the same.

The compound of the present invention can be prepared by reducing the compound and then reacting it with 8,4,5,6-titrahydrophthalic anhydride to produce a compound of the general formula [wherein R and R have the same meanings as above]. ] The tetrahydrophthal derivative shown does not cause any problematic phytotoxicity to major crops such as corn, wheat, rice, soybean, and cotton, and has sufficient herbicidal efficacy against many weeds (patent application). (Sho 59-198245).

The compound of the present invention typically has the general formula: [wherein R1 represents the same meaning as above]. ] A nitrobenzoxazine derivative represented by the general formula % [wherein R represents the same meaning as above and X represents a halogen atom. ] in a solvent in the presence of a base,
It can be produced by reacting at θ°C to 80°C, preferably 10°C to 80°C.

The amounts of reagents used in this reaction are 1.0 to 1.5 equivalents of the halide [ff] and 1.0 to 1.5 equivalents of the base, relative to the nitrobenzoxazine derivative [11 equivalents]. .

Examples of the solvent include aromatic hydrocarbons such as toluene and benzene, amides such as N,N-dimethylformamide, sulfur compounds such as dimethylsulfoxide, nitriles such as acetonitrile, water, etc., or mixtures thereof.

Examples of the base include sodium hydride, potassium carbonate, sodium hydroxide, potassium hydroxide, and the like.

After the completion of the reaction, the reaction solution is added with water and then subjected to post-treatments such as organic solvent extraction and concentration, or if necessary, purified by operations such as recrystallization and chromatography. A compound is obtained.

Note that nitrobenzoxazine [111], which is a raw material compound in the above method, can be produced by the following method. That is, in the general formula, R1 represents a lower alkyl group, and R2 represents the same meaning as above. ] − for phenoxyacetic acid nitrides represented by 8
~ 80 equivalents, preferably 5 to 20 equivalents of iron powder, in acetic acid water, preferably in the presence of a co-solvent such as ethyl acetate, at 60°C to 120°C [by reductive cyclization] Formula [wherein R2 represents the same meaning as above]. ] was obtained, and then the benzoxazine derivative [M] and a sulfuric acid-nitric acid mixture were mixed to -10''0 to 1
It can be produced by reacting at 0°C and selectively nitrating the 6-position of the benzoxazine ring.

In addition, this raw material compound phenoxyacetic acid varnish f/l
/ [V] is J= Am, Chem, Soc,
8194 (1959).

Hereinafter, the present invention will be explained in more detail with reference to production examples and reference examples.

Production Example 0.06 f of sodium hydride was suspended in 8-N,N-dimethylformamide and cooled to 0°C. To this, 0.57 F of 7-fluoro-6-nitro-2H-1,4-benzoxazin-8(4H)-one was added at 0°C to 5°C,
Stirred for 80 minutes. Next, 0.85 f of propargyl bromide was added to this reaction solution, the temperature was gradually raised to room temperature, and the mixture was reacted for 6 hours. Water was added, extracted with ethyl acetate, the extract was washed with water, dried, and concentrated, and the resulting residue was purified by silica gel thin layer chromatography (developing solvent: ethyl acetate: n-hexane = 1:1), 7-Fluoro-6-nitro-4-propargyl-2H-1,4-benzoxazine-
0.471 of 3(4H)-one was obtained. m, p, 10
Table 1 shows some of the compounds of the invention that can be prepared by a method such as 9.1°.

Table 1 General formula iron powder 86.421 was suspended in 5% fraudulent acid water 691Rt,
Heated to 80°C. To this was added a solution of 15.861 ethyl 5-fluoro-2-nitrophenoxacetate dissolved in 65m acetic acid and 65m ethyl acetate, and
The mixture was heated under reflux at C for 8 hours. The residue was filtered and the P solution was extracted with ethyl acetate. The extract was washed with water and then with aqueous sodium bicarbonate, dried, and concentrated to give pale yellow crystals of 7-fluoro-2, 1, and 7-fluoro-2.
6.82f of 4-benzoxazin-8(4H)-one was obtained.

m, p, 186.7 "C Similarly, α-methyl-5-fluoro-2-nitrophenoxyethyl acetate,!, t), 7-fluoro-2-methyl-2H-1,4-benzoxazine-8 (4f()-
Got it on.

m, p, 151.8"C Reference example 2 7-fluoro-2H-1,4-benzoxazine-8 (
4) 2.0 g of ()-one was dissolved in 80% sulfuric acid water 801. This was cooled to 0°C to 6°C, and 60% nitric acid 1.6
1 was gradually added dropwise at θ°C to 5°C, and the mixture was stirred at the same temperature for 80 minutes.

Claims (2)

[Claims] (1) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R^1 represents an alkyl group, alkenyl group, alkynyl group, alkoxyalkyl group, or alkoxyalkoxyalkyl group, and R^2 is a hydrogen atom or Represents a methyl group. ] A 4-substituted nitrobenzoxazine derivative. (2) General formula ▲ Numerical formula, chemical formula, table, etc. are available ▼ [In the formula, R^2 represents a hydrogen atom or a methyl group. ] A nitrobenzoxazine derivative represented by the general formula R^1-X [wherein R^1 represents an alkyl group, an alkenyl group, an alkynyl group, an alkoxyalkyl group, or an alkoxyalkoxyalkyl group, and R^2 is a hydrogen atom or represents a methyl group, and X represents a chlorine atom, a bromine atom or an iodine atom. ] There are general formulas ▲ mathematical formulas, chemical formulas, tables, etc. ▼ which are characterized by reacting with a halide represented by ▼ [In the formula, R^1 and R^2 represent the same meanings as above. ] A method for producing a 4-substituted nitrobenzoxazine derivative.