42831-50-5

Basic information

• Product Name: 5-Methyl-4-isoxazolecarboxylic acid
• Synonyms: TIMTEC-BB SBB005909;5-METHYLISOXAZOLE-4-CARBOXYLIC ACID;5-METHYL-4-ISOXASOLECARBOXYLIC ACID;5-METHYL-4-ISOXAZOLECARBOXYLIC ACID;5-Methyl-4-Isooxazolecarboxylic Acid;5-METHYLISOXAZOLE-4-CARBOXYLIC;5-MethylIsoxazole-4-CarboxalicAcid,Leflunomide;4-Isoxazolecarboxylic acid,5-Methyl
• CAS NO: 42831-50-5
• Molecular Formula: C₅H₅NO₃
• Molecular Weight: 127.1
• EINECS: 1312995-182-4
• Product Categories: Acids and Derivatives;Heterocycles;Isoxazoles, Oxadiazoles, Oxazoles;Carboxylic Acids;Oxazoles, Isoxazoles & Benzoxazoles;Oxazole&Isoxazole;Organic acids;(intermediate of leflunomide);Heterocyclic Compounds;Carboxylic Acids;Oxazoles, Isoxazoles & Benzoxazoles;Building Blocks;Heterocyclic Building Blocks;Isoxazoles;Intermediates;Intermediates & Fine Chemicals;Pharmaceuticals
• Mol File: 42831-50-5.mol
• Article Data: 11

Chemical Properties

• Melting Point: 144-148 °C(lit.)
• Boiling Point: 308.3 °C at 760 mmHg
• Flash Point: 140.3 °C
• Appearance: cream to brown solid
• Density: 1.348 g/cm³
• Vapor Pressure: 0.000297mmHg at 25°C
• Storage Temp.: Sealed in dry,Room Temperature
• Solubility: DMSO (Slightly), Methanol (Slightly)
• PKA: 2.85±0.25(Predicted)
• BRN: 116000
• CAS DataBase Reference: 5-Methyl-4-isoxazolecarboxylic acid(CAS DataBase Reference)
• NIST Chemistry Reference: 5-Methyl-4-isoxazolecarboxylic acid(42831-50-5)
• EPA Substance Registry System: 5-Methyl-4-isoxazolecarboxylic acid(42831-50-5)

Safety Data

• Hazard Codes: Xi,F
• Statements: 36/37/38-37/38-36-10
• Safety Statements: 22-26-36/37/39-36-16
• WGK Germany: 3
• HazardClass: IRRITANT
• Hazardous Substances Data: 42831-50-5(Hazardous Substances Data)

Usage

Uses

Different sources of media describe the Uses of 42831-50-5 differently. You can refer to the following data:
1. An intermediate for synthesis of Leflunomide (L322750). Herbicidal activities towards Digitaria ciliaris
2. 5-Methylisoxazole-4-carboxylic Acid (Leflunomide EP Impurity D) is an intermediate for synthesis of Leflunomide (L322750). Herbicidal activities towards Digitaria ciliaris.

Flammability and Explosibility

Nonflammable

InChI:InChI=1/C5H5NO3/c1-3-4(5(7)8)2-6-9-3/h2H,1H3,(H,7,8)/p-1

Upstream product

• 100367-49-5 (5-methylisoxazol-4-yl)methanol 
• 51135-73-0 5-methylisoxazole-4-carboxylic acid ethyl ester 
• 3788-94-1 2-ethoxymethylene-3-oxobutanoic acid ethyl ester 
• 134653-70-6 ethyl 2-[(dimethylamino)methylene]-3-oxobutanoate 
• 33142-24-4 2-formyl-3-oxo-butyric acid ethyl ester 

Downstream Products

• 67305-24-2 5-methylisoxazole-4-carbonyl chloride 
• 803684-84-6 N-[2-(4-bromobenzoyl)-7-methoxybenzofuran-3-yl]-5-methylisoxazole-4-carboxamide 
• 688757-65-5 5-bromo-2-(4-chlorobenzoyl)-3-(5-methylisoxazole-4-carbonyl)aminobenzo[b]furan 
• 803684-82-4 N-[5-bromo-2-(4-cyanobenzoyl)benzofuran-3-yl]-5-methylisoxazole-4-carboxamide 
• 688757-01-9 (E)-N-{2-acetyl-5-[1-methyl-3-oxo-3-(4-phenylpiperazin-1-yl)-1-propenyl]benzofuran-3-yl}-5-methylisoxazole-4-carboxamide 
• 803684-91-5 (E)-N-[2-(4-cyanobenzoyl)-5-(2-diethylcarbamoyl-1-methylvinyl)benzofuran-3-yl]-5-methylisoxazole-4-carboxamide 
• 803684-81-3 (E)-N-(2-acetyl-5-{2-[2-(3,4-dimethoxyphenyl)ethylcarbamoyl]-1-methylvinyl}benzofuran-3-yl)-5-methylisoxazole-4-carboxamide 
• 688757-69-9 (E)-N-[2-(4-{2-[2-(3,4-dimethoxyphenyl)ethylcarbamoyl]-1-methylvinyl}benzoyl)-7-methoxybenzofuran-3-yl]-5-methylisoxazole-4-carboxamide 
• 93276-75-6 (4-Cyano-5-methylisoxazol-3-yl)acetic acid 
• 93276-74-5 3-(5-methylisoxazol-4-yl)isoxazol-5(4H)-one 
• 75706-12-6 Leflunomide 
• 99803-72-2 N-(5-Methyl-4-isoxazolylcarbonyl)-piperidine 

Relevant articles and documents

Preparation method of (by machine translation)

The invention relates to a novel process for preparing flutamipide by using a pharmaceutical active pharmaceutical ingredient, wherein ethyl acetoacetate is taken as a raw material and mixed with hydroxylamine hydrochloride to obtain fluticide. The process not only can better control the content of 3 - methyl isomers and 4 - trifluoromethylaniline in the baflunomide product, and is higher in yield and more concise. The industrial wastewater generated by the process is less in waste gas, environmentally friendly, capable of effectively reducing production cost and corrosion to equipment. (by machine translation)

Synthesis and in vivo antifibrotic activity of novel leflunomide analogues

Novel Leflunomide analogues were synthesized and evaluated in vivo against thioacetamide (TAA) induced liver fibrosis in rats. All the animals which were treated with the new analogues showed improved or comparable survival rates to those treated with Leflunomide. Animals which were treated with compounds 8d, 8e, 9 and 11 have shown improved liver parameters than Leflunomide treated animals. Histopathology of the liver has shown that compound 8a is the most active compound, which decreases fibrosis to a minimal level and compounds 8c, 8e and 11 are active compounds with fibrosis score 2-3 which is better than that of Leflunomide.

AN IMPROVED PROCESS FOR PREPARATION OF LEFLUNOMIDE

This invention describes a process for the preparation of N-(4-trifluoromethyl)-5-methylisoxazole-4-carboxamide commonly known as leflunomide comprising : (a) reacting ethylaceto acetate, triethylorthoformate, and acetic anhydride with simultaneous distillation to form ethyl ethoxymethyleneacetoacetic ester; (b) reacting the ethyl ethoxymethyleneacetoacetic ester with aqueous hydroxylamine without using any external base and without any distillation to form ethyl-5-methylisoxazole-4-carboxylate; (c) reacting the ethyl-5-methylisoxazole-4-carboxylate with strong acid to form -5-methylisoxazole-4-carboxylic acid; (d) 5-methylisoxazole-4-carboxylic acid is reacted with thionyl chloride in presence of N, N-Dimethylformamide and equimolar of 4-trifluoromethylaniline without any external base to obtain highly pure Leflunomide.