DE4101380A1 - PROCESS FOR THE PREPARATION OF 4H-3,1-BENZOXAZINE-4-ONEN - Google Patents

Abstract

Production of 4H-3,1-benzoxazine-4-ones of formula (I) in which: R<1> is hydrogen, C1-C4-alkyl, C1-C4-alkoxy, carboxyl, sulpho, nitro or halogen; R<2> is C1-C20-alkyl, phenyl or phenylalkyl with 1 to 4 C atoms in the alkyl group, whereby a phenyl nucleus may be substituted by one or two C1-C4-alkyl groups, C1-C3-halogen alkyl groups, C1-C4-alkoxy groups, C1-C3-halogen alkoxy groups, C1-C4-alkyl mercapto groups, C1-C3-halogen alkyl mercapto groups, carboxyl groups, sulpho groups, C1-C4-alkyl sulphonyl groups, C1-C3-halogen alkyl sulphonyl groups, nitro groups or halogen atoms; and n is 1 or 2; by the reaction of isato acid anhydrides of formula (II) with acyl halides of formula (III) in which X is chlorine or bromine, by conducting the reaction at an outside temperature of 215 to 280 DEG C and causing the reaction components (II and III) to react together for at least 4 hours at this temperature.

Description

The present invention relates to an improved method for Preparation of 4H-3,1-benzoxazin-4-ones of the general formula I

in the
R ¹ denotes hydrogen, C ₁ -C ₄ -alkyl, C ₁ -C ₄ -alkoxy, carboxyl, sulfo, nitro or halogen,
R ^{2 is} C ₁ -C₂₀-alkyl, phenyl or phenylalkyl having 1 to 4 carbon atoms in the alkyl group, wherein a present phenyl nucleus by one or two C ₁ -C ₄ alkyl groups, C ₁ -C ₃ -haloalkyl, C ₁ -C ₄ alkoxy groups, C ₁ -C ₃ haloalkoxy, C ₁ -C ₄ -Alkylmercaptogruppen, C ₁ -C ₃ -Halogenalkylmercaptogruppen, carboxyl groups, sulfo groups, C ₁ -C ₄ alkylsulfonyl, C ₁ -C ₃ -Halogenalkylsulfonylgruppen , Nitro groups or halogen atoms, and
n is 1 or 2,
by reaction of isatoic anhydrides of the general formula II

with acyl halides of the general formula III

in which X denotes chlorine or bromine.

In the references J. prakt. Chemistry, Vol. 30 (1884), pp 484-487, and Vol. 33 (1886), p. 18-31, describe E. v. Meyer and Th. Bellmann Process for the preparation of "benzoylanthranil" (2-phenyl-4H-3,1 benzoxazin-4-one) by heating unsubstituted isatoic anhydride  (mistakenly referred to as isatoic acid) with excess Benzoyl chloride to boiling or "in a closed tube" at 210 ° C. The Implementation is characterized as incomplete ("leaves the solution much unchanged isatoic acid, which Benzoylanthranil added Further information on reaction time, batch size, stoichiometry of the Feedstocks or yield are not made.

DE-A 35 14 183 relates to a process for the preparation of given if substituted 2-phenyl-4H-3,1-benzoxazin-4-ones by reaction a corresponding anthranilic acid with a corresponding benzoyl halide in the presence of a base (acylation) and ring closure Dehydration (cyclization).

In DE-AS 25 56 590 a process for the preparation of Benzoxazines, especially of 2-alkyl- or 2-aryl-4H-3,1-benzoxazin-4-ones, described in which an isatoic anhydride with an acylating agent in Form of a carboxylic acid anhydride or an acid halide in the presence effective proportions of a tertiary amine is implemented.

However, all of these methods are still economically viable unsatisfactory, whether the yields are still too low, or whether it is that cumbersome multistep reaction paths are trodden or expensive Auxiliary chemicals must be used with.

Object of the present invention, therefore, it was a simple, effi Aient and economical process for the preparation of 4H-3,1-Benz to provide oxazine-4-one I.

Accordingly, the method defined above was found, which thereby characterized in that the reaction at an outside temperature of 215 to 280 ° C and reactants II and III at least 4 hours at this temperature react with each other.

In a preferred embodiment, the outside temperature for the Reaction at 220 to 250 ° C. Under outside temperature, the temperature is the Sheath of the reaction vessel, in particular in this sheath located heating fluid to understand.

The internal temperature, d. H. the temperature of the reaction mixture itself, should ideally be the same as the outside temperature; in practice However, the internal temperature is usually a few degrees lower than the Outside temperature. It should also be noted that when using a Acyl halide III, whose boiling point is lower than that for the  According to the invention claimed temperature range, against At the beginning of the reaction, the internal temperature is equal to the boiling point of III is (eg 197 ° C when benzoyl chloride is used), when the Concentration of free acyl halide III in the reaction mixture but the Indoor temperature rapidly towards the value of the set Outside temperature rises.

The reaction time is at least for the temperature range mentioned 4 hours, then normally a turnover of 80 to 95% is reached. It is more favorable, however, to run the reaction for at least 5 hours leave, because after this time the turnover is usually at 95% or higher lies. After 6 hours reaction time, the reaction is usually practically complete.

The reaction is conveniently carried out at atmospheric pressure. On Working in closed reaction vessels under autogenous pressure or in Autoclave at elevated pressures is not required; this is already out safety issues, because in the implementation of gases (Hydrogen chloride and carbon dioxide) are released, which are dissipated Need to become.

1.0 to 1.5 mol of acyl halide III are added per mole of isatoic anhydride II on. A larger excess of III often causes the Reaction mixture not necessary for rapid Abreagieren temperature reached. Particularly favorable is an amount of 1.0 to 1.3 mol III, in particular from 1.05 to 1.2 mol III per mole II.

As acyl halides III come acyl bromides (X = Br) and especially Acyl chlorides (X = Cl) into consideration.

As radicals R¹, which are attached to the benzene nucleus of the heterocyclic system in 5, 6, 7- and / or 8-position, come next to hydrogen in consideration:

• C ₁ -C ₄ -alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl,
• C ₁ - to C ₄ -alkoxy groups such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy and methylenedioxy,
• - Carboxyl groups, which are suitably present as free acids should,  
• - Sulfo groups which suitably exist as free acids should,
• - nitro groups and
• - Halogen atoms such as fluorine, chlorine and bromine.

For R ¹ , preference is given to methyl groups, methoxy groups, halogen atoms and in particular hydrogen alone.

The number n of radicals R ¹ is 2 or preferably 1.

Suitable radicals R ² in the 2-position of the benzoxazin-4-one system are:

• - straight or branched C ₁ -C₂₀ alkyl, z. For example, methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, iso-nonyl , n-decyl, n-undecyl, n-dodecyl, n-tridecyl, iso-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl or n-eicosyl,
• - phenyl and
• - Phenylalkyl having 1 to 4 carbon atoms in the alkyl group, z. Benzyl, 2-phenylethyl, 3-phenylpropyl or 4-phenylbutyl.

A present phenyl nucleus in the radical R ² may be substituted by two or preferably one of the following radicals in the o-, m- or p-position:

• C ₁ -C ₄ -alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl,
• C ₁ -C ₃ -haloalkyl, such as chloromethyl, dichloromethyl, trichloromethyl or trifluoromethyl,
• C ₁ -C ₄ -alkoxy, such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy or methylenedioxy,
• C ₁ -C ₃ -haloalkoxy, such as difluoromethoxy, trifluoromethoxy, chlorodifluoromethoxy, 1,1,2,2-tetrafluoroethoxy or 1,1,2-trifluoro-2-chloroethoxy,
• C ₁ -C ₄ -alkylmercapto, such as methylmercapto, ethylmercapto, n-propylmercapto or n-butylmercapto,
• C ₁ -C ₃ -haloalkylmercapto, such as difluoromethylmercapto, trifluoromethylmercapto, chlorodifluoromethylmercapto or 1,1,2,2-tetrafluoroethyl mercapto,
• Carboxy, suitably as free acid,
• Sulfo, suitably as free acid,
• C ₁ -C ₄ -alkylsulfonyl, such as methylsulfonyl, ethylsulfonyl, n-propylsulfonyl or n-butylsulfonyl,
• C ₁ -C ₃ -haloalkylsulfonyl, such as chloromethylsulfonyl or trifluoromethylsulfonyl,
• - Nitro or
• - Halogen such as fluorine, chlorine or bromine.

The following radicals are preferred for R ² :

• straight-chain or branched C ₁ -C ₄ -alkyl, in particular methyl,
• unsubstituted phenyl,
• C ₁ -C ₄ -alkyl, in particular methyl-substituted phenyl,
• C ₁ -C ₃ -haloalkyl-substituted phenyl,
• phenyl substituted by C ₁ -C ₄ -alkoxy, in particular by methoxy,
• C ₁ -C ₃ -haloalkoxy-substituted phenyl,
• C ₁ -C ₃ -haloalkylmercapto-substituted phenyl,
• C ₁ -C ₄ -alkylsulfonyl, in particular methylsulfonyl-substituted phenyl,
• C ₁ -C ₃ -haloalkylsulfonyl-substituted phenyl,
• nitro substituted phenyl and
• - Halogen substituted phenyl.

After the reaction, the compounds I obtained according to the purified by conventional methods, for example by recrystallization or Distillation, and / or if desired by the usual methods be made up, for example by granulation from the melt before or after a cleaning step.

The process according to the invention allows 4H-3,1-benzoxazin-4-ones I in simple way efficient, d. H. in high yields, and economically cheap to produce. You do not need any auxiliary chemicals like this Solvents or catalysts. The implementation is in a short time almost completely expired, resulting in a high space-time Yield is reflected. The product is usually in sufficiently pure Form, since the reaction takes place without appreciable side reactions, so that for many applications further cleaning operations unnecessary.

The 4H-3,1-benzoxazin-4-ones I are important compounds for various uses, eg. B. as a plant protection agent, remedy, detergent additives or UV stabilizers. Thus, compounds I with halogen, methyl or methoxy for R ¹ and halophenyl, haloalkylphenyl, haloalkoxyphenyl, haloalkylmercaptophenyl or haloalkylsulfonylphenyl having in each case 1 to 3 C atoms in the alkyl group for R ^{2 can be used} as selectively acting herbicides. Certain 2-substituted 4H-3,1-benzoxazin-4-ones are useful as cold bleach activators in detergents.

example Preparation of 2-phenyl-4H-3,1-benzoxazin-4-one

163.1 g (1.0 mol) of isatoic anhydride and 154.7 g (1.1 mol) of benzoyl chloride were at a heating jacket temperature of the reaction vessel from 220 to C. with stirring, with hydrogen chloride and Carbon dioxide escaped. The internal temperature in the reaction mixture increased during the reaction from 197 ° C to 215 ° C. Out of the reaction Released gas volume could change the sales depending on the Reaction time can be determined:  

Reaction time (h) Sales (%) 1 8th 2 32 3 72 4 93 5 99 6 100

After completion of gas evolution after 6 hours, the crude product was at 160 ° C / l mbar purified by distillation. There were 227 g of the title compound (corresponding to a yield of 94%) in the form of a colorless oil, which crystallized on cooling, obtained.

Claims (3)

1. A process for the preparation of 4H-3,1-benzoxazin-4-ones of the general formula I. in the
R ¹ denotes hydrogen, C ₁ -C ₄ -alkyl, C ₁ -C ₄ -alkoxy, carboxyl, sulfo, nitro or halogen,
R ^{2 is} C ₁ -C ₂₀ alkyl, phenyl or phenylalkyl having 1 to 4 carbon atoms in the alkyl group, wherein a present phenyl nucleus is represented by one or two C ₁ -C ₄ alkyl groups, C ₁ -C ₃ haloalkyl groups, C ₁ -C ₄ alkoxy, C ₁ -C ₃ haloalkoxy, C ₁ -C ₄ captogruppen -Alkylmer, C ₁ -C ₃ -Halogenalkylmercaptogruppen, carboxyl groups, sulfo groups, C ₁ -C ₄ alkylsulfonyl, C ₁ -C ₃ - Haloalkyl substituted haloalkyl, nitro groups or halogen atoms may be substituted, and
n is 1 or 2,
by reaction of isatoic anhydrides of the general formula II with acyl halides of the general formula III in which X denotes chlorine or bromine,
characterized in that the reaction is carried out at an external temperature of from 215 to 280 ° C and the reactants II and III react for at least 4 hours at this temperature. 2. A process for the preparation of 4H-3,1-benzoxazin-4-ones I after Claim 1, characterized in that the reaction at a Outside temperature of 220 to 250 ° C makes. 3. A process for the preparation of 4H-3,1-benzoxazin-4-ones I after Claim 1 or 2, characterized in that per mole Isatoic anhydride II 1.0 to 1.5 mol of acyl halide III is used.