76508-35-5

Basic information

• Product Name: Isopropyl 4-Hydroxy-2H-1,2-benzothiazine-3-carboxylate 1,1-Dioxide (Piroxicam Impurity I)
• Synonyms: Isopropyl 4-Hydroxy-2H-1,2-benzothiazine-3-carboxylate 1,1-Dioxide (Piroxicam Impurity I);Isopropyl 4-Hydroxy-;Isopropyl 4-Hydroxy- (Piroxicam Impurity I);4-Hydroxy-2H-1,2-benzothiazine-3-carboxylic acid 1-methylethyl ester 1,1-dioxide;NSC 642708;4-Hydroxy-1,1-dioxo-1,2-dihydro-1lambda*6*-benzo[e][1,2]thiazine-3-carboxylic acid isopropyl ester
• CAS NO: 76508-35-5
• Molecular Formula: C₁₂H₁₃NO₅S
• Molecular Weight: 283.30032
• Product Categories: Aromatics;Impurities;Intermediates & Fine Chemicals;Pharmaceuticals;Sulfur & Selenium Compounds
• Mol File: 76508-35-5.mol

Chemical Properties

• Melting Point: 170℃ (ethanol )
• Boiling Point: 453.09°C at 760 mmHg
• Flash Point: 227.821°C
• Appearance: /
• Density: 1.444g/cm³
• Vapor Pressure: 0mmHg at 25°C
• Refractive Index: 1.608
• CAS DataBase Reference: Isopropyl 4-Hydroxy-2H-1,2-benzothiazine-3-carboxylate 1,1-Dioxide (Piroxicam Impurity I)(CAS DataBase Reference)
• NIST Chemistry Reference: Isopropyl 4-Hydroxy-2H-1,2-benzothiazine-3-carboxylate 1,1-Dioxide (Piroxicam Impurity I)(76508-35-5)
• EPA Substance Registry System: Isopropyl 4-Hydroxy-2H-1,2-benzothiazine-3-carboxylate 1,1-Dioxide (Piroxicam Impurity I)(76508-35-5)

Safety Data

• Hazardous Substances Data: 76508-35-5(Hazardous Substances Data)

Usage

Uses

Piroxicam impurity I.

InChI:InChI=1/C12H13NO5S/c1-7(2)18-12(15)10-11(14)8-5-3-4-6-9(8)19(16,17)13-10/h3-7,13-14H,1-2H3

Upstream product

• 6639-62-9 methyl 3-oxo-2,3-dihydrobenzo[d][1,2]thiazol-2-acetate 1,1-dioxide 
• 683-60-3 sodium isopropylate 
• 76524-15-7 2-(Isopropoxycarbonylmethyl-sulfamoyl)-benzoic acid isopropyl ester 
• 76508-37-7 (1,1,3-Trioxo-1,3-dihydro-1λ⁶-benzo[d]isothiazol-2-yl)-acetic acid isopropyl ester 
• 128-44-9 saccharin sodium salt 

Downstream Products

• 118854-48-1 isopropyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide 
• 15448-99-4 N-methylsaccharin 
• 5510-09-8 1,1-dioxo-2,3-dihydro-1H-1λ⁶-benzo[e][1,2]thiazin-4-one 

Relevant articles and documents

Process for obtaining 4-hydroxy-2-methyl-N-(2-pyridyl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide

A process for obtaining 4-hydroxy-2-methyl-N-(2-pyridyl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide, which may be used as a non-steroidal analgesic and anti-inflammatory drug. The process comprises reacting saccharin sodium with isopropyl chloroacetate in dimethylformamide, reacting the resultant isopropyl 3-oxo-1,2-benzoisothiazoline-2-acetate 1,1-dioxide with sodium isopropylate in isopropanol to produce an intermediate which, when methylated in an aqueous-alcoholic basic medium with dimethyl sulfate, gives an intermediate compound which when condensed with 2-aminopyridine in xylene, yields 4-hydroxy-2-methyl-N-(2-pyridyl)-2H-1,2-benzothiazone-3-carboxamide 1,1-dioxide.

3-Oxo-1,2-benzoisothiazoline-2-acetic Acid 1,1-Dioxide Derivatives. I. Reaction of Esters with Alkoxides

Reaction of 3-oxo-1,2-benzoisothiazoline-2-acetic acid alkyl esters 1,1-dioxide (1a-d) with alkaline alkoxides was carried out under various conditions.Under mild conditions, o-(N-carboxymethylsulfamyl)benzoic acids dialkyl esters (2a-d) were obtained with good yields.Reaction of 1a-d or 2a-d with sodium alkoxide under drastic conditions afforded 4-hydroxy-2H-1,2-benzothiazine-3-carboxylic acid alkyl esters 1,1-dioxide (3a-d).Transesterification was observed when esters 1b-d were treated with sodium methoxide in methanol.Esters 3a-d were hydrolyzed in concentrated aqueous sodium hydroxide affording the acid 6.Attempts to recrystallize 6 from water resulted in its decarboxylation to give 2H-1,2-benzothiazine-4-(3H)one 1,1-dioxide (7).Compound 6 could not be obtained by acid hydrolysis of esters 3a-d or by rearrangement of 3-oxo-1,2-benzoisothiazoline-2-acetic acid 1,1-dioxide (8).Different experimental evidence supports the suggestion that rearrangement took place by ethanolysis of the carboxamide linkage affording the open sulfonamides (fast step) followed by a Dieckmann cyclization (slow step).It was demonstrated that transesterification took place in the open sulfonamides 2.