25057-89-0

Basic information

• Product Name: Bentazone
• Synonyms: 3,4-Dihydro-3-isopropyl-1H-2,1,3-benzothiadiazin-4-one 2,2-Dioxide;Basagran 480;BasaMais;Bazargan;Bentazone solution;Bentazon, Herbicide Mix;Bentazone,aqueous(25%);Basagran (BASF)
• CAS NO: 25057-89-0
• Molecular Formula: C₁₀H₁₂N₂O₃S
• Molecular Weight: 240.28
• EINECS: 246-585-8
• Product Categories: HERBICIDE;Alphabetic;BA - BH;BA - BHPesticides&Metabolites;A-BAlphabetic;Alpha sort;B;Herbicides;Others;Pesticides&Metabolites;Agro-Products;Aromatics;Application: A contact herbicide Selective contact herbicide
• Mol File: 25057-89-0.mol

Chemical Properties

• Melting Point: 137-139°C
• Boiling Point: 395.7 °C at 760 mmHg
• Flash Point: 2 °C
• Appearance: White/Solid
• Density: 1.3387 (rough estimate)
• Vapor Pressure: 1.8E-06mmHg at 25°C
• Refractive Index: 1.5650 (estimate)
• Storage Temp.: APPROX 4°C
• Solubility: Chloroform (Slightly), Methanol (Slightly)
• PKA: pKa (24°): 3.3
• Water Solubility: 0.5g/L(20 oC)
• Merck: 13,1051
• BRN: 530220
• CAS DataBase Reference: Bentazone(CAS DataBase Reference)
• NIST Chemistry Reference: Bentazone(25057-89-0)
• EPA Substance Registry System: Bentazone(25057-89-0)

Safety Data

• Hazard Codes: Xn,F
• Statements: 22-36-43-52/53-20/21/22-11
• Safety Statements: 2-24-37-61-36-26-16
• RIDADR: UN 1648 3/PG 2
• WGK Germany: 2
• RTECS: DK9900000
• Hazardous Substances Data: 25057-89-0(Hazardous Substances Data)

Usage

Uses

Used in Agricultural Industry:
Bentazone is used as a selective, contact, post-emergence herbicide for controlling a variety of annual and perennial broad-leaved weeds in most grass and legume crops. It is particularly effective in crops such as beans, corn, mint, soybeans, rice, and peanuts. The sodium salt of bentazon, referred to as sodium bentazon, is commonly used as the active ingredient in products formerly marketed in the U.S.
Additionally, bentazone is used in the selective post-emergent control of broadleaf weeds and sedges in various crops, including alfalfa, asparagus, cereals, clover, digitalis, dry peas, flax, garlic, grasses, green lima beans, onions, potatoes, snap beans for seed, sorghum, soybeans, and sugarcane. Although not currently registered in the U.S., it is reported to be used in most European countries.

Trade name

ASAGIO?; BAS 351-H?; BASAGRAN?; BENDIOXIDE?; BENTA?; BLAST?; ENTRY?; LADDOK?; LEADER?; PLEDGE?; STORM?

Safety Profile

Moderately toxic by ingestion and skin contact. An experimental teratogen. Other experimental reproductive effects. When heated to decomposition it emits very toxic fumes of SO, and NOx.

Potential Exposure

A potential danger to those involved in the manufacture, formulation or application of this selective postemergent thiadiazine herbicide.

Environmental Fate

Soil. Under aerobic conditions, bentazone was reported to degrade to 6- and 8-hydrox ybentazone compounds. In addition, anthranilic acid and isopropylamide were reported as soil hydrolysis products (Otto et al., 1978). Persistence in soil is less than 6 weeks (Hartley and Kidd, 1987). Bentazone is readily adsorbed onto organic carbon and therefore, is not expected to leach to groundwater (Abernathy and Wax, 1973). The dissipation half life of bentazone in field soil is 5 days (Ross et al., 1989).Plant. Undergoes hydroxylation of the aromatic ring and subsequent conju-gation in plants (Otto et al., 1978; Hartley and Kidd, 1987) forming 6- and 8-hydroxybentazone compounds (Otto et al., 1978). The half-life in and/or on plants is 2–3 days (Photolytic. Humburg et al. (1989) reported that 30% degradation of bentazone on glass plates occurred when exposed to UV light (λ = 200–400 nm); however, no photoproduct(s) were reported. The natural sunlight and simulated sunlight irradiation ofChiron et al. (1995) investigated the photodegradation of bentazone (20 μg/L) in distilled water and Ebro River water using an xenon arc irradiation. In distilled water, bentazone completely disappeared after 16 hours of irradiation. Photodegradation appeared to follow pseudo-first-order kinetics with a half-life of about 2.5 hours. The presence of humic substances (4 mg/L) increased the rate of photodegradation and the disappearance of bentazone was achieved in 8 hours. No significant breakdown photoproducts were identified.

Metabolic pathway

14C-Bentazon degrades in soils under conventional tillage and no-tillage (3-18 years) with varying histories of bentazon application. The half-life for bentazon degradation ranges from 4.6 to 49.5 days; half-lives for some no-tillage soils with the longest histories of application are lower than those of conventional tillage soils. Half-lives for soils with no bentazon history are 3-11 times higher than the half- lives of those previously exposed to bentazon. N- Methylbentazon is the most consistently observed metabolite. The other metabolites identified in soils result from hydroxylation on the phenyl ring and the cleavage of the benzothiadiazine ring, yielding 6- and 8-hydroxybentazons and anthranilic acid via 2-amino-N-isopropylbenzamide.

Incompatibilities

Keep away from flammable materials, heat and flame. Risk of fire and explosion if formulations contain flammable/explosive solvents.

Waste Disposal

In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office.

InChI:InChI=1/C10H12N2O3S/c1-7(2)12-10(13)8-5-3-4-6-9(8)11-16(12,14)15/h3-7,11H,1-2H3

Synthetic route

α-picoline (109-06-8) + 2-amino-N-isopropylbenzamide (30391-89-0) → Bentazon (25057-89-0)

Conditions	Yield
With chlorosulfonic acid; trichlorophosphate In water; 1,2-dichloro-ethane	96.7%
With chlorosulfonic acid; trichlorophosphate In water; 1,2-dichloro-ethane	96.8%
With sulfur trioxide; trichlorophosphate In water; 1,2-dichloro-ethane	94.1%

N-isopropyl-N'-o-carbomethoxy-phenyl-sulfamide (86071-21-8) → Bentazon (25057-89-0)

Conditions	Yield
With sodium methylate In methanol at 40℃; for 2h;

2-carbomethoxyaniline (134-20-3) → Bentazon (25057-89-0)

Conditions	Yield
Multi-step reaction with 2 steps 1: Et3N / toluene / 1 h / 80 °C 2: MeONa / methanol / 2 h / 40 °C View Scheme

N,N-dimethyl-cyclohexanamine (98-94-2) + 2-amino-N-isopropylbenzamide (30391-89-0) → Bentazon (25057-89-0)

Conditions	Yield
With sulfur trioxide; trichlorophosphate In 1,2-dichloro-ethane

2-amino-N-isopropylbenzamide (30391-89-0) → Bentazon (25057-89-0)

Conditions	Yield
With sulfur trioxide; triethylamine; trichlorophosphate In 1,2-dichloro-ethane
With sulfur trioxide; 2,3-Dimethylaniline; trichlorophosphate In 1,1-dichloroethane
With sulfur trioxide; trichlorophosphate In quinoline; 1,1-dichloroethane

Bentazon (25057-89-0) → mecoprop, potassium salt

Conditions	Yield
In isobutanolic potassium hydroxide	97.3%

2-biphenylmethanol (2928-43-0) + Bentazon (25057-89-0) → 1-biphenyl-2-ylmethyl-3-isopropyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	91%

Bentazon (25057-89-0) + 1-bromomethyl-4-nitro-benzene (100-11-8) → 3-Isopropyl-1-(4-nitro-benzyl)-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one (132575-80-5)

Conditions	Yield
With potassium carbonate In acetonitrile for 0.333333h; Heating;	89%

1-naphthalene methanol (4780-79-4) + Bentazon (25057-89-0) → 3-isopropyl-1-naphthalen-1-ylmethyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	88%

pyridine-4-methanol (586-95-8) + Bentazon (25057-89-0) → 3-isopropyl-2,2-dioxo-1-pyridin-4-ylmethyl-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	86%

3-Nitrobenzyl alcohol (619-25-0) + Bentazon (25057-89-0) → 3-isopropyl-1-(3-nitro-benzyl)-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	82%

methyl 5-(bromomethyl)-furan-2-carboxylate (70117-25-8) + Bentazon (25057-89-0) → 5-(3-Isopropyl-2,2,4-trioxo-3,4-dihydro-2H-2λ6-benzo[1,2,6]thiadiazin-1-ylmethyl)-furan-2-carboxylic acid methyl ester (132575-81-6)

Conditions	Yield
With potassium carbonate In acetonitrile for 0.333333h; Heating;	79%

2-Naphthalenemethanol (1592-38-7) + Bentazon (25057-89-0) → 3-isopropyl-1-naphthalen-2-ylmethyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	76%

biphenyl-4-yl methanol (3597-91-9) + Bentazon (25057-89-0) → 1-biphenyl-4-ylmethyl-3-isopropyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	76%

Bentazon (25057-89-0) + α-bromoacetophenone (70-11-1) → 3-Isopropyl-2,2-dioxo-1-(2-oxo-2-phenyl-ethyl)-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one (132575-79-2)

Conditions	Yield
With potassium carbonate In acetonitrile for 0.333333h; Heating;	75%

3-(bromomethyl)-1,1'-biphenyl (14704-31-5) + Bentazon (25057-89-0) → 1-biphenyl-3-ylmethyl-3-isopropyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With sodium hydride In N,N-dimethyl-formamide at 70℃; for 3h;	74%

zinc(II) nitrate (10196-18-6) + Bentazon (25057-89-0) → zinc(II) 1-dehydro-3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxidate trihydrate

Conditions	Yield
With sodium hydroxide In water Bazagran is added to a soln. of NaOH, filtn., a soln. of the metal salt is added to the filtrate with stirring.; The ppt. is left under the mother soln. for 1 day, concg., filtn. under reduced pressure, washing with cold water, drying in air, elem. anal.;	71%

1-bromo-butane (109-65-9) + Bentazon (25057-89-0) → 1-Butyl-3-isopropyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one (132575-78-1)

Conditions	Yield
With potassium carbonate In acetonitrile for 0.333333h; Heating;	69%

3,5-bis(1,1-dimethylethyl)benzenemethanol (77387-57-6) + Bentazon (25057-89-0) → 1-(3,5-di-tert-butyl-benzyl)-3-isopropyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	68%

3-iodobenzylalcohol (57455-06-8) + Bentazon (25057-89-0) → 1-(3-iodo-benzyl)-3-isopropyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	67%

manganese(II) nitrate + Bentazon (25057-89-0) → manganese(II) 1-dehydro-3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxidate trihydrate

Conditions	Yield
With sodium hydroxide In water Bazagran is added to a soln. of NaOH, filtn., a soln. of the metal salt is added dropwise to the filtrate with stirring.; The ppt. is left under the mother soln. for 1 day, filtn. under reduced pressure, washing with cold water, drying in air, elem. anal.;	65%

1,1-Diphenylmethanol (91-01-0) + Bentazon (25057-89-0) → 1-benzhydryl-3-isopropyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	63%

benzoyl chloride (98-88-4) + Bentazon (25057-89-0) → 1-benzyl-3-isopropyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one (67594-07-4)

Conditions	Yield
With potassium carbonate In acetonitrile for 0.333333h; Heating;	52%

3,5-di-tert-butyl-4-hydroxybenzyl alcohol (88-26-6) + Bentazon (25057-89-0) → 1-(3,5-di-tert-butyl-4-hydroxy-benzyl)-3-isopropyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	45%
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;

2-(2-Hydroxyethyl)pyridine (103-74-2) + Bentazon (25057-89-0) → 3-isopropyl-2,2-dioxo-1-(2-pyridin-2-yl-ethyl)-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	39%

(4-hydroxyphenyl)methanol (623-05-2) + Bentazon (25057-89-0) → 1-(4-hydroxy-benzyl)-3-isopropyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	21%

1-(2-Hydroxy-ethyl)-pyrrolidine-2,5-dione (18190-44-8) + Bentazon (25057-89-0) → 1-[2-(3-isopropyl-2,2,4-trioxo-3,4-dihydro-2H-2λ6-benzo[1,2,6]thiadiazin-1-yl)-ethyl]-pyrrolidine-2,5-dione

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	20%

Bentazon (25057-89-0) + cyclohexanol (108-93-0) → 1-cyclohexyl-3-isopropyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one

Conditions	Yield
With di-isopropyl azodicarboxylate; triphenylphosphine In tetrahydrofuran at 20℃; Mitsunobu reaction;	12%

Bentazon (25057-89-0) → 2-isopropyl-3-oxo-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide (17507-67-4)

Conditions	Yield
In hexane Irradiation;

benzene-1,2-diol (120-80-9) + Bentazon (25057-89-0) → 1-(3,4-dihydroxy-phenyl)-3-isopropyl-2,2-dioxo-2,3-dihydro-1H-2λ6-benzo[1,2,6]thiadiazin-4-one + C26H26N4O8S2

Conditions	Yield
laccase from Polyporus pinsitus at 25℃; for 4h; pH=3.0 - 7.0; Substitution; Enzymatic reaction;

[14C]methyl iodide (16170-82-4) + Bentazon (25057-89-0) → N-<14C>methylbentazon

Conditions	Yield
With tetra(n-butyl)ammonium hydrogensulfate In dichloromethane for 12h; Methylation;

Upstream product

• 86071-21-8 N-isopropyl-N'-o-carbomethoxy-phenyl-sulfamide 
• 134-20-3 2-carbomethoxyaniline 
• 98-94-2 N,N-dimethyl-cyclohexanamine 
• 30391-89-0 2-amino-N-isopropylbenzamide 
• 109-06-8 α-picoline 

Downstream Products

• 132575-79-2 3-Isopropyl-2,2-dioxo-1-(2-oxo-2-phenyl-ethyl)-2,3-dihydro-1H-2λ⁶-benzo[1,2,6]thiadiazin-4-one 
• 132575-80-5 3-Isopropyl-1-(4-nitro-benzyl)-2,2-dioxo-2,3-dihydro-1H-2λ⁶-benzo[1,2,6]thiadiazin-4-one 
• 67594-07-4 1-benzyl-3-isopropyl-2,2-dioxo-2,3-dihydro-1H-2λ⁶-benzo[1,2,6]thiadiazin-4-one 

Relevant articles and documents

2,1,3-Benzothiadiazine derivatives: Synthesis and screening versus PDE4 enzyme

A series of N-1,3 disubstituted 2,1,3-benzothiadiazine derivatives (BTDs) were synthesized and evaluated for their inhibitory activity versus enzymatic isoform PDE4 extracted from U937 cell line. Some of the tested compounds showed a high PDE4 inhibitory activity at 100:μM and the IC50 value of the most interesting terms were evaluated. The structure-activity relationships of these compounds showed that the 3,5-di-tert-butyl-4-hydroxybenzyl moiety at N-1 position is important to obtain activity at micromolar level as previously reported. For the same compounds the antioxidant activity were evaluated highlighting 14 as the most significative one. The introduction of other bulky substituents in N-1 position is detrimental.

Solid mixtures based on sulfonylureas and adjuvants

Solid mixtures comprising a) an active compound from the group consisting of the sulfonylureas, and b) an alkylpolyglucoside.

Method for the production of 3-isopropyl-1H-2, 1,3-benzothiadiazine-4 (3H)-one-2,2-dioxide

A process for preparing 3-isopropyl-1H-2,1,3-benzothiadiazin-4 (3H)-one 2,2-dioxide (I) or a salt of I which comprises reacting anthranilic isopropylamide II simultaneously with sulfur trioxide or chlorosulfonic acid in the presence of an organic base or with adducts of sulfur trioxide and organic bases and phosphorus oxychloride at from 50° C. to the reflux temperature, followed, if appropriate, by conversion into its salts, is described.

Solid mixtures based on sulfonylureas and adjuvants

A solid ixture comprising a) an active ingredient from the group of the sulfonylureas and b) an alkyl ether of a copolymer of C2-C4-alkylene oxides.

Herbicidal mixtures having a synergistic effect

PCT No. PCT/EP96/03996 Sec. 371 Date Feb. 17, 1998 Sec. 102(e) Date Feb. 17, 1998 PCT Filed Sep. 12, 1996 PCT Pub. No. WO97/10714 PCT Pub. Date Mar. 27, 1997A composition comprising at least one sulfonylurea of the formula I wherein R1 is substituted alkyl; halogen; a group ER6 (E=O, S or NR7); COOR8; NO2; S(O)oR9; SO2NR10R11; or CONR10R11; R2 is hydrogen, alkyl, alkenyl, alkynyl, halogen, alkoxy, haloalkoxy, haloalkyl, alkylsulfonyl, nitro, cyano or alkylthio; R3 is F, CF3, CF2Cl, CF2H, OCF3, OCF2Cl, or, if R1 is CO2CH3 and R2 is simultaneously fluorine, R3 is Cl, or, if R1 is CH2CF3 or CF2CF3, R3 is methyl, or, if R4 is OCF3 or OCF2Cl, R3 is OCF2H or OCF2Br; R4 is alkoxy, alkyl, alkylthio, alkylamino, dialkylamino, halogen, haloalkyl or haloalkoxy; and R5 is hydrogen, alkoxy or alkyl; or an enviromentally compatible salt of I, and an aryloxyalkanoic acid selected from the group consisting of 2,4-D, 2,4-DB, clomeprop, dichlorprop, dichlorprop-P, dichlorprop-P (2,4-DP-P), fenoprop (2,4,5-TP), fluoroxypyr, MCPA, MCPB, mecoprop, mecoprop-P, napropamide, napropanilide, triclopyr, and an enviromentally compatible salt thereof exhibits a synergistic herbicidal effect.

Substituted pyridinesulfonamide compound or its salt, process for preparing the same, and herbicide containing the same

A substituted pyridinesulfonamide compound or its salt represented by the following general formula (I): STR1 wherein A is CH or N; when A is CH, R1 and R2 may be either each independently a member selected from the group consisting of unsubstituted or substituted alkyl groups, unsubstituted or substituted alkenyl groups, unsubstituted or substituted cycloalkyl groups, and unsubstituted or substituted phenyl groups; when A is N, R1 is an unsubstituted or substituted alkyl group, R2 is an unsubstituted or substituted alkyl group, or an unsubstituted or substituted alkoxy group; and X and Y are each independently a member selected from the group consisting of alkyl groups and alkoxy groups, is disclosed. This compound is useful as the effective ingredient of a herbicide showing a wide weed-control spectrum even if used in a small amount.

Substituted pyridinesulfonamide compounds or their salts, process for preparing the same, and herbicides containing the same

A substituted pyridinesulfonamide compound or its salt represented by the following general formula (I): wherein R1 is an unsubstituted or substituted alkyl group; R2 is an unsubstituted or substituted alkyl group, or an unsubstituted or substituted alkoxy group; and X and Y are each independently a member selected from the group consisting of alkyl groups and alkoxy groups, is disclosed. This compound is useful as the effective ingredient of a herbicide showing a wide weed-control spectrum even if used in a small amount.

Preparation of N-phenyl(pyridyl) sulfonyldiamides

A process for the preparation of N-phenyl(pyridyl)sulfonyldiamides by reacting a 2-aminobenzoic acid (nicotinic acid) derivative with sulfur trioxide, chlorosulfonic acid or an adduct of sulfur trioxide with a tertiary amine in the presence of a diluent and of a tertiary amine, and reacting the resulting sulfamate with a primary amine and a phosphorus halide, or by reacting a 2-aminobenzoic acid (nicotinic acid) derivatives with an N-alkyl(cycloalkyl)sulfamic acid or a salt of this acid in the presence of a diluent and of a phosphorus halide.

Manufacture of 2,1,3-thiadiazin-4-one-2,2-dioxide derivatives

New and valuable process for the manufacture of 2,1,3-thiadiazin-4-one-2,2-dioxide derivatives by reaction of anthranilic acid amide or aminopyridine carboxamide derivatives with sulfur trioxide derivatives to give the sulfamic acid salts, followed by cyclization of these salts.

Production of 2,1,3-benzothiadiazin-4-one-2,2-dioxides

2,1,3-Benzothiadiazin-4-one-2,2-dioxides are produced by the reaction of esters of anthranilic acid with a sulfamic acid halide in the presence of a solvent and a base at a temperature of from 20° to 100°C. The products are starting materials for the production of dyes and plant protection agents.