JP2002220381A - Manufacturing method of 3,4-dihydro-1,2,3-oxathiazines or salts thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method by which 3,4-dihydro-1,2,3-oxathiazines or salts thereof are manufactured industrially advantageously. SOLUTION: A sulfonic acid represented by formula (1) (wherein R1 and R2 are each independently hydrogen atom or an organic group which is inert to the reaction; R3 is hydrogen atom, an organic group which is inert to the reaction, an organic group which combines with nitrogen atom to form a salt or an inorganic metal atom; and X is hydrogen atom or an organic or inorganic salt which forms a salt with a sulfonate group) is subjected to the cyclized dehydration reaction in the presence of an acid hydride to obtain a 3,4- dihydro-1,2,3-oxathiazine represented by formula (2) or a salt thereof. An acid hydride which is composed of at least an acid selected from the group consisting of a sulfonic acid, a halogenated sulfuric acid, pyrophosphoric acid, nitric acid and boric acid is used as this acid hydride.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a 3,4-dihydro-1,1 useful for obtaining a sweetener or the like in the food industry.
The present invention relates to a method for producing 2,3-oxathiazines or a salt thereof.

[0002]

2. Description of the Related Art A compound having a 3,4-dihydro-1,2,3-oxathiazine ring has an acidic hydrogen atom bonded to a nitrogen atom in the molecule, and thus can form a salt with a base. Among the salts formed, non-toxic salts (eg, Na
Some of the salts (eg, salts, K salts, Ca salts) have a strong sweetness, and such salts are used as sweeteners in the food industry.

As a method for producing the aforementioned 3,4-dihydro-1,2,3-oxathiazines, for example, Angevante Chemie International Edition, Vol. 12, No. 10, (1973), No. 86
9-876 (or DE-A-245 306)
3), acetoacetamido-N-sulfonic acid halide (fluoride or chloride) is allowed to act on a base (methanolic KOH or the like) to open the ring to give 3,4-dihydro-1,2,3-oxathiazines ( 6-methyl-3,
4-dihydro-1,2,3-oxathiazin-4-one-2,2-dioxide or a salt thereof). On the other hand, the acetoacetamide-N-
Sulfonic halides are obtained by reacting halosulfonyl isocyanates with a suitable acetoacetylating agent. However, in such a method, halosulfonyl isocyanate or amide sulfo halide used as a starting material is a special compound and is not easy to handle, so that it is not suitable as an industrial method.

[0004] As another method, Japanese Patent Laid-Open Publication No.
No. 48, Japanese Patent Publication No. 5-70627 and Japanese Patent Publication No. 6-25189 disclose a method of reacting acetoacetamido-N-sulfonic acid or a salt thereof with SO ₃ in an inert organic solvent to carry out a cyclization dehydration reaction. By subjecting it to ring closure,
A method for producing 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one-2,2-dioxide or a salt thereof is disclosed. However, even in such a method, attention must be paid to the handling of SO _{3 to be} used.
Liquid SO ₂ , methylene chloride and the like are used as inert solvents for SO ₃ . SO ₂ is a liquefied gas and is not easy to handle in terms of odor and toxicity.

[0005] In such a production method, no effective cyclizing dehydrating agent has been found as a substitute for SO ₃ , and there is no other means than using the above-mentioned solvent.

[0006]

Accordingly, an object of the present invention is to use a cyclized dehydrating agent which is relatively easy to handle, and
An object of the present invention is to provide a method for industrially and advantageously producing dihydro-1,2,3-oxathiazines or salts thereof.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, cyclization and dehydration of acetoacetamido-N-sulfonic acids or salts thereof have been carried out.
In the method for producing -dihydro-1,2,3-oxathiazines, it has been found that by using a specific acid anhydride as a cyclizing dehydrating agent, the target compound can be obtained even with a non-halogen solvent, The present invention has been completed.

That is, in the present invention, the following formula (1)

[0009]

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Wherein R ¹ and R ² are the same or different and each represent a hydrogen atom or a reaction-inactive organic group, and R ³ is a hydrogen atom, a reaction-inactive organic group, or a nitrogen atom; X represents a hydrogen atom or a sulfonate group and an organic or inorganic base which forms a salt with a sulfonic acid represented by the following formula: It is subjected to a cyclization dehydration reaction and the following formula (2)

[0011]

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(Wherein R ¹ , R ² and R ³ are as defined above)
To produce 3,4-dihydro-1,2,3-oxathiazines or a salt thereof. As the acid anhydride,
An acid anhydride composed of at least one selected from sulfonic acid, halogenated sulfuric acid, pyrophosphoric acid, nitric acid and boric acid is used. The acid anhydride may be a sulfonic anhydride or a mixed acid anhydride containing at least sulfonic acid. R ¹ and R ² may be a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an acyl group, an aralkyl group, an aryl group, or the like;
³ may be a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an acyl group, an aralkyl group, an aryl group, an organic group or an inorganic metal atom which forms a salt by binding to a nitrogen atom. The acid anhydride may be used in a ratio of about 1 to 20 mol per 1 mol of the sulfonic acids. The sulfonic acids are acetoacetamide-N-
It may be a sulfonate. 3,4-dihydro-1,
Examples of the 2,3-oxathiazines or salts thereof include 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one-2,2-dioxide and salts thereof.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the sulfonic acids of the formula (1) are subjected to a cyclization reaction (particularly a cyclization dehydration reaction) in the presence of an acid anhydride. -Dihydro-
Produce 1,2,3-oxathiazines or salts thereof.

In the above formula (1), R ¹ , R ² and R ³
The organic group inert to the reaction represented by is not particularly limited as long as it is inert to the reaction, and may be an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an acyl group, an aralkyl group, and an aryl group. And the like.

The alkyl group includes a linear or branched C
_1-10Alkyl group (for example, methyl group, ethyl group,
Butyl, isobutyl, tert-butyl, etc.
C_{1- 6}Alkyl group, etc.). Alkenyl group
Is a linear or branched C_2-10Alkenyl groups (eg, bi
Nil, allyl, isopropenyl, 1-butenyl
Group such as a group or a 2-butenyl group_2-5Alkenyl group)
included. Alkynyl groups include linear or branched C_2-10
Alkynyl group (for example, ethynyl group, propynyl group, 1
-Butynyl group, 2-butynyl group, etc._2-5Alkynyl
Groups). Examples of cycloalkyl groups include
For example, cyclopropyl, cyclobutyl, cyclopent
C, such as_3-10Cycloalkyl group
(Preferably C_4-8Cycloalkyl group). A
The sil group includes a linear or branched C_2-10Aliphatic acyl group
(E.g., acetyl, propionyl, butyryl,
Isobutyryl group, valeryl group, etc.) or C_7-11Good
Aromatic acyl groups (eg, benzoyl, toluyl,
Etc.). Aralkyl groups include:
C _6-10Aryl-C_1-4Alkyl groups (eg, benzyl
And the like, and the aryl group is phenyl
C such as a group_6-10And an aryl group.

In the above formula (1), the organic group forming a salt by bonding to the nitrogen atom represented by R ³ includes an organic group forming an ammonium salt or an amine salt, for example, an alkyl group (for example, C Examples thereof include a _1-10 alkyl group), a cycloalkyl group (eg, a C _3-12 cycloalkyl group), an aryl group (eg, a C _6-10 aryl group), and an aralkyl group (eg, a benzyl group).

In R ³ , the inorganic metal atoms forming a salt include alkali metals (Group 1A metals in the periodic table) such as Na, K and Li, and alkaline earth metals (Group 2A metals in the periodic table) such as Mg, Ca and Sr. Periodic table 3B of metals, Al, Ga, etc.
Group metal, transition metal (eg, group 3A metal of the periodic table, group 4A metal of the periodic table, group 5A metal of the periodic table, group 6A metal of the periodic table, M
Periodic Table 7A metals such as n, Periodic Table 8 metals such as Fe, Periodic Table 1B metals such as Cu, Ag, and Au; Periodic Table 2B metals such as Zn; Periodic Table 4B metals; and Periodic Table 5B
Group metals). Preferred inorganic metal atoms include
Examples thereof include 1-3 valent metals, for example, alkali metals (such as Na and K), alkaline earth metals (such as Mg and Ca), Al, and transition metals (such as Mn and Fe). In consideration of economy, safety, and the like, alkali metals such as Na and K are often used.

The organic base which forms a salt with the sulfonate group represented by X in the above formula (1) includes amines corresponding to amine salts, for example, aliphatic amines [primary amines (eg, methylamine, Ethylamine), second
Tertiary amines (eg, dimethylamine, ethylmethylamine, etc.), tertiary amines (eg, trimethylamine,
Alicyclic amines (eg, cyclopentylamine, cyclohexylamine, etc.), aromatic amines (eg, monoarylamines such as aniline and dimethylaniline, diarylamines such as diphenylamine, and triarylamines such as triphenylamine) And cyclic amines (for example, pyridine, quinoline, piperidine and derivatives thereof). Preferred amines are aliphatic amines, among which tertiary amines are preferred.

In X, examples of the inorganic base which forms a salt with a sulfonate group include ammonia, alkali metal hydroxides (eg, sodium hydroxide, potassium hydroxide, etc.) and alkali metal carbonates (eg, sodium carbonate,
Potassium carbonate, etc.), alkali metal bicarbonates (eg, sodium bicarbonate, potassium bicarbonate, etc.), hydroxides of alkaline earth metals (eg, calcium hydroxide, magnesium hydroxide, etc.), carbonic acid of alkaline earth metals Hydrogen salts (eg, calcium bicarbonate, magnesium bicarbonate, etc.) and the like can be mentioned.

In the above formulas (1) and (2), R ¹ to
R ³ and X can be appropriately combined, and for example, the following combinations are preferred.

R ¹ and R ² : hydrogen atom, C _1-4 alkyl group R ³ : hydrogen atom, C _1-4 alkyl group, alkali metal, alkaline earth metal X: aliphatic amine (particularly tertiary amine) , Ammonium, alkali metals and alkaline earth metals Preferred sulfonic acids of the formula (1) include acylacetamide-N-sulfonates wherein R ¹ is an alkyl group and R ² and R ³ are hydrogen atoms. Among them, acetoacetamide-N-sulfonate wherein R ¹ is a methyl group,
In particular, acetoacetamide-N wherein X is ammonium
-Ammonium sulfonates (particularly tertiary ammonium salts) are preferred.

In the present invention, the acid anhydride acts as a cyclizing agent (such as a cyclizing dehydrating agent) for the sulfonic acids (1). Such acid anhydrides include halogenated sulfuric acid (fluorosulfuric acid, chlorosulfuric acid, etc.), pyrophosphoric acid (pyrophosphoric acid; halogenated pyrophosphoric acid such as fluoropyrophosphoric acid, etc.), nitric acid, boric acid (orthoboric acid, metaboric acid, etc.) )
Inorganic acid such as sulfonic acid, organic phosphoric acid (C _1-4 alkyl phosphoric acid such as methyl phosphoric acid; mono C _1-4 phosphoric acid such as monomethyl phosphate and monoethyl phosphate)
Acid anhydrides composed of organic acids such as alkyl esters). The acids (inorganic acids and organic acids) may be used alone or in combination of two or more. The acid anhydride may be a mixed acid anhydride containing at least the above acid, or may be a mixture of a plurality of acid anhydrides. Preferred acid anhydrides are sulfonic anhydrides and acid anhydrides composed of acids containing at least sulfonic acid.

Examples of the sulfonic acid include alkanesulfonic acids (eg, methanesulfonic acid, ethanesulfonic acid, etc.).
_1-6 alkanesulfonic acid, preferably C _1-4, such as alkanesulfonic acid), haloalkane sulfonic acid (trifluoromethanesulfonic acid, trifluoromethanesulfonic acid, fluoro sulfonic acid, trihalo mono- to such chloromethane sulfonic acid C _1- Aliphatic sulfonic acids such as ₆ alkanesulfonic acids, preferably halo C _1-4 alkanesulfonic acids, and the like; and aromatic sulfonic acids [benzenesulfonic acid,
and C _6-10 aromatic sulfonic acid which may have a substituent (C _1-4 alkyl group, halogen atom, etc.) such as p-toluenesulfonic acid]. Preferred sulfonic acids, haloalkane sulfonic acid (di- or tri-C _1-2 alkanesulfonic acids), and the like, especially trihalomethane acid. Halogen atoms in haloalkanesulfonic acids include fluorine, chlorine, bromine and iodine atoms,
Particularly, fluorine and chlorine atoms are preferred.

The acid anhydride composed of the sulfonic acid or the like may be used alone, or may be an anhydride of a mixed acid of an acid such as the sulfonic acid and another acid (mixed acid anhydride). . Examples of the acid constituting the other acid or another acid anhydride include sulfuric acid (orthosulfuric acid, pyrosulfuric acid, etc.), phosphoric acid (phosphoric acid such as orthophosphoric acid, metaphosphoric acid, etc .; halogenated orthophosphoric acid such as fluoroorthophosphoric acid, etc.) ), Chloric acid (chloric acid, chlorous acid, etc.), inorganic acids such as chromic acid and antimonic acid (especially oxyacids); carboxylic acids (aliphatic C _1-10 monocarboxylic acids such as acetic acid and propionic acid; maleic acid) , Aliphatic _C4-10 dicarboxylic acids such as fumaric acid; aromatic _C7-12 carboxylic acids such as benzoic acid and phthalic acid; halogenated carboxylic acids (halides of the carboxylic acids, for example, fluoroacetic acid, triacetic acid) Examples thereof include organic acids such as halo C _1-6 aliphatic carboxylic acids such as fluoroacetic acid, chloroacetic acid, and dichloroacetic acid, and preferably trihalo C _1-4 aliphatic carboxylic acids.

Examples of the mixed acid include combinations of the above-mentioned acids such as haloaliphatic carboxylic acids-haloalkanesulfonic acids such as trifluoroacetic acid-trifluoromethanesulfonic acid. Trimethylsilyltrifluoromethanesulfonate (trifluoromethylsulfonic acid and trimethylsilyl acid) Condensates containing haloalkanesulfonic acids, such as condensates with chlorides and the like.

The acid anhydride is usually used in an amount of at least 1 mol (for example, 1 to 20 mol) per 1 mol of the sulfonic acid,
It is preferably used at a ratio of about 1 to 10 mol, particularly about 1 to 5 mol.

The cyclodehydration of the sulfonic acid (1) as a substrate can be carried out in the presence or absence of a solvent. As the solvent, various inorganic or organic solvents inert to the reaction (particularly, acid anhydride) can be used.
Usually, an organic solvent inert to the reaction is used. As the solvent, a substantially anhydrous solvent is usually used.
As such an organic solvent, a halogen-based organic solvent (e.g., a haloalkane such as dichloromethane, dichloroethane, and chloroform) may be used. However, when the acid anhydride is used, a non-halogen-based organic solvent may be used. The reaction can proceed.

Examples of such non-halogen organic solvents include ketones (for example, aliphatic ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; alicyclic ketones such as cyclohexanone) and ethers (for example, diethyl ether). Chain ethers such as diisopropyl ether, 1,2-dimethoxyethane, cellosolve, carbitol, diglyme, diethylene glycol dimethyl ether; aromatic ethers such as anisole, 1,2-dimethoxybenzene, diphenyl ether; cyclic such as tetrahydrofuran, dioxolan, dioxane Ethers), lower carboxylic acids (eg,
Formic acid, acetic acid, propionic acid, butyric acid, etc.), nitriles (eg, acetonitrile, propionitrile, butyronitrile, benzonitrile, etc.), sulfoxides (eg, dimethylsulfoxide, sulfolane, 2-methylsulfolane, 3-methylsulfolane, etc.) Alcohols (e.g., aliphatic alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol and t-butanol; alicyclic alcohols such as cyclopentanol and cyclohexanol; benzyl alcohol Such as aromatic alcohols), aliphatic hydrocarbons (eg, pentane, hexane,
Octane), alicyclic hydrocarbon (eg, cyclohexane, etc.), aromatic hydrocarbon (eg, benzene, toluene, xylene, ethylbenzene, etc.), esters (eg, methyl acetate, ethyl acetate, butyl acetate, methyl propionate) And amides (formamide, acetamide, dimethylformamide (DMF), dimethylacetamide, etc.). These solvents may be used alone or in combination of two or more. Particularly preferred solvents are ethers (such as chain ethers such as diethyl ether), nitrites (such as acetonitrile), and the like.

The ratio of the solvent is not particularly limited, and is, for example, 1 to 100 parts by weight of the sulfonic acid (1) as the substrate.
It can be selected from a wide range of about 2000 parts by weight, preferably about 100 to 2000 parts by weight. The substrate concentration in the reaction mixture is not particularly limited, and is, for example, about 0.1 to 50% by weight, preferably about 0.5 to 30% by weight, and more preferably about 1 to 15% by weight.

The reaction is usually carried out under normal pressure, but may be carried out under reduced pressure or under increased pressure. In addition, the reaction is carried out at an appropriate temperature (for example, a temperature higher than the melting point of the reaction system and lower than the boiling point), for example, about -70 to 200 ° C, preferably -4.
It can be carried out at a temperature of about 0 to 70 ° C, and at room temperature (15 to
(About 30 ° C.). The reaction time is not particularly limited, and is, for example, 0.1 to 10 hours, preferably 0.1 to 10 hours.
To 5 hours, more preferably about 0.1 to 2 hours.

In the reaction, the order of adding or mixing the raw materials,
The form of addition is not particularly limited. For example, an acid anhydride may be added to the sulfonic acid (1) as the substrate, or the sulfonic acid (1) may be added to the acid anhydride. Further, the sulfonic acid (1) and the acid anhydride may be simultaneously introduced into the reaction system. Each of the sulfonic acids (1) and the acid anhydride may be used without being diluted with a solvent or the like, or may be used as a solution diluted with a solvent.

The above reaction can be carried out either in a batch system or a continuous system.

The thus obtained 3,4-dihydro
Xy-1,2,3-oxathiazines or salts thereof (2)
For example, 6-methyl-3,4-dihydro-
1,2,3-oxathiazin-4-one-2,2-di
Oxide, 6-ethyl-3,4-dihydro-1,2,3
-Oxathiazin-4-one-2,2-dioxide,
6-n-propyl-3,4-dihydro-1,2,3-o
Xiathiazin-4-one-2,2-dioxide, 6-
i-propyl-3,4-dihydro-1,2,3-oxa
6- such as thiazin-4-one-2,2-dioxide
C_1-4Alkyl-3,4-dihydro-1,2,3-oxo
Satiazin-4-one-2,2-dioxide; 6-f
Enyl-3,4-dihydro-1,2,3-oxathiazi
6-ary such as n-4-one-2,2-dioxide
-3,4-dihydro-1,2,3-oxathiazine-
4-one-2,2-dioxide; 5-methyl-6-methyl
Tyl-3,4-dihydro-1,2,3-oxathiazine
-4-one-2,2-dioxide, 5-methyl-6
Ethyl-3,4-dihydro-1,2,3-oxathiazi
5,6-di, such as n-4-one-2,2-dioxide
C_1-4Alkyl-3,4-dihydro-1,2,3-oxo
Satiazin-4-one-2,2-dioxide;
Enyl-6-methyl-3,4-dihydro-1,2,3-
Oxathiazin-4-one-2,2-dioxide and the like
5-aryl-6-C_1-4Alkyl-3,4-dihydride
B-1,2,3-oxathiazin-4-one-2,2-
Dioxide; 5-methyl-6-phenyl-3,4-di
Hydro-1,2,3-oxathiazin-4-one-2,
5-C such as 2-dioxide_1-4Alkyl-6-ali
-3,4-dihydro-1,2,3-oxathiazine
-4-one-2,2-dioxide; 6-cyclopentene
-3,4-dihydro-1,2,3-oxathiazine-
4-one-2,2-dioxide, 6-cyclohexyl
-3,4-dihydro-1,2,3-oxathiazine-4
6-C such as -on-2,2-dioxide _3-8Cyclo
Alkyl-3,4-dihydro-1,2,3-oxathia
Zin-4-one-2,2-dioxide; 5-cyclope
Nthyl-6-methyl-3,4-dihydro-1,2,3-
Oxathiazin-4-one-2,2-dioxide, 5
-Cyclohexyl-6-methyl-3,4-dihydro-
1,2,3-oxathiazin-4-one-2,2-di
5-C such as quiside_3-8Cycloalkyl-6-C_1-4A
Alkyl-3,4-dihydro-1,2,3-oxathiazi
N-4-one-2,2-dioxide; 5-methyl-6
-Cyclopentyl-3,4-dihydro-1,2,3-o
Xiathiazin-4-one-2,2-dioxide, 5-
Methyl-6-cyclohexyl-3,4-dihydro-1,
2,3-oxathiazin-4-one-2,2-dioxa
5-C such as id_1-4Alkyl-6-C_3-8Cycloalkyl
-3,4-dihydro-1,2,3-oxathiazine-
4-one-2,2-dioxide; 6-vinyl-3,4
-Dihydro-1,2,3-oxathiazin-4-one-
6-C such as 2,2-dioxide_2-4Alkenyl-
3,4-dihydro-1,2,3-oxathiazine-4-
On-2,2-dioxide; 6-acetyl-3,4-
Dihydro-1,2,3-oxathiazin-4-one-
6-C such as 2,2-dioxide_2-6Acyl-3,4
-Dihydro-1,2,3-oxathiazin-4-one-
2,2-dioxide and salts thereof.
You.

In particular, oxathiazines wherein R ¹ is a methyl group in the above formula (2) (for example, 6-methyl-3,
4-Dihydro-1,2,3-oxathiazin-4-one-2,2-dioxide) is part of its physiologically acceptable salts (eg, salts with Na, K, Ca, etc.). It is preferred because it is used as a sweetener in the food industry.
Among them, a salt with potassium is particularly useful as acesulfame (acesulfame K).

After completion of the reaction, the resulting 3,4-dihydro-
The 1,2,3-oxathiazines or salts thereof can be easily separated and purified by conventional separation and purification means, for example, distillation, concentration, extraction, recrystallization, chromatography and the like.
For example, ice or water (eg,
About 1 to 10 times the amount of acid anhydride, ice or water), and the mixture is separated into an organic layer and an aqueous layer, and a suitable water-insoluble (or immiscible) solvent [ In particular, a non-halogen solvent, for example, an organic mono- or dicarboxylic acid ester (eg, esters exemplified in the above-mentioned reaction solvent) and the like] are added, and the 3,4-dihydro-1,2,2,2 remaining in the aqueous layer is added. You may extract and collect 3-oxathiazine. Further, the organic layer containing 3,4-dihydro-1,2,3-oxathiazine (including the extract from the above-mentioned aqueous layer) may be concentrated by drying with a conventional drying agent (eg, sodium sulfate). It may be concentrated without drying. After the concentration, if necessary, the product may be further purified by recrystallization or the like.

The 3,4-dihydro-1,2,3-oxathiazines thus obtained, whose physiologically acceptable salts (such as potassium salts) are useful as sweeteners in the food industry. .

[0037]

According to the present invention, since a specific acid anhydride is used as the cyclizing dehydrating agent, the handling is relatively easy.
3,4-Dihydro-1,2,3-oxathiazines or salts thereof can be industrially advantageously produced. Further, since the specific acid anhydride is used, the reaction can proceed even in a non-halogen solvent, and the environmental load can be reduced.

[0038]

EXAMPLES The present invention will be described below in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 2.2 ml of trifluoromethanesulfonic anhydride (10 mm) was placed in 10 ml of dichloromethane cooled to -30 ° C.
ol), and 1.4 g (5 mmol) of acetoacetamido-N-triethylammonium sulfonate was further added.
Was dissolved in 10 ml of dichloromethane dropwise over about 10 minutes. After 2 hours, 10 ml of water and 10 ml of ethyl acetate were added. After separating the organic layer, the aqueous layer was extracted twice with ethyl acetate. The organic layer was dried over sodium sulfate (anhydrous) and concentrated under reduced pressure to give 6-methyl-
3,4-dihydro-1,2,3-oxathiazine-4-
On-2,2-dioxide was obtained in a yield of 20%.

Example 2 In 10 ml of acetonitrile cooled to -30 ° C., 2.2 ml (10 mm) of trifluoromethanesulfonic anhydride was added.
ol), and 1.4 g (5 mmol) of acetoacetamido-N-triethylammonium sulfonate was further added.
Was dissolved in 10 ml of acetonitrile and added dropwise over about 10 minutes. After 2 hours, 10 ml of water and 10 ml of ethyl acetate were added. After separating the organic layer, the aqueous layer was extracted twice with ethyl acetate. The organic layer was dried over sodium sulfate (anhydrous) and concentrated under reduced pressure to give 6-methyl-
3,4-dihydro-1,2,3-oxathiazine-4-
On-2,2-dioxide was obtained in a yield of 5%.

Claims (9)

[Claims] [Claim 1] The following formula (1) (Wherein R ¹ and R ² are the same or different and each represent a hydrogen atom or a reaction-inactive organic group, and R ³ binds to a hydrogen atom, a reaction-inactive organic group or a nitrogen atom to form X represents an organic group or an inorganic metal atom to be formed, X represents a hydrogen atom or a base which forms a salt with a sulfonate group), and subjected to a cyclization dehydration reaction in the presence of an acid anhydride; The following formula (2) (Wherein R ¹ , R ² and R ³ are the same as described above), which is a method for producing 3,4-dihydro-1,2,3-oxathiazines or a salt thereof, wherein As
A process for producing 3,4-dihydro-1,2,3-oxathiazine or a salt thereof using an acid anhydride composed of at least one selected from sulfonic acid, halogenated sulfuric acid, pyrophosphoric acid, nitric acid and boric acid. 2. In the formulas (1) and (2), R ¹ and R ² represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an acyl group, an aralkyl group,
Or an aryl group, wherein R ³ is a hydrogen atom, an alkyl group,
The production method according to claim 1, wherein the production method is an alkenyl group, an alkynyl group, a cycloalkyl group, an acyl group, an aralkyl group, an aryl group, or an organic group or an inorganic metal atom which forms a salt by binding to a nitrogen atom. 3. The method according to claim 1, wherein the acid anhydride is a sulfonic anhydride or a mixed acid anhydride containing at least sulfonic acid. 4. The method according to claim 1, wherein the acid anhydride is an anhydride of halo C _1-4 alkanesulfonic acid or a mixed acid anhydride containing at least halo C _1-4 alkanesulfonic acid. 5. The method according to claim 1, wherein the acid anhydride is an anhydride of trihalomethanesulfonic acid or an anhydride of a mixed acid containing at least trihalomethanesulfonic acid. 6. The method according to claim 1, wherein the acid anhydride is used in a ratio of 1 to 20 mol per 1 mol of the sulfonic acids of the formula (1). 7. The method according to claim 1, wherein the sulfonic acid of the formula (1) is acetoacetamide-N-sulfonic acid salt. 8. The production method according to claim 1, wherein the sulfonic acid of the formula (1) is a tertiary ammonium salt of acetoacetamido-N-sulfonic acid. 9. The method according to claim 9, wherein the 3,4-dihydro-1,2,3-oxathiazine or a salt thereof is 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one-2,2-
The production method according to claim 1, which is a dioxide or a salt thereof.