| Identification | More | [Name]
5-Methyl-4-isoxazolecarboxylic acid | [CAS]
42831-50-5 | [Synonyms]
5-METHYL-4-ISOXASOLECARBOXYLIC ACID
5-METHYL-4-ISOXAZOLECARBOXYLIC ACID
5-METHYLISOXAZOLE-4-CARBOXYLIC ACID
TIMTEC-BB SBB005909
5-Methyl-4-Isooxazolecarboxylic Acid
5-METHYLISOXAZOLE-4-CARBOXYLIC
5-MethylIsoxazole-4-CarboxalicAcid,Leflunomide
4-Isoxazolecarboxylic acid,5-Methyl
5-METHYLISOXAZOLE-4-CARBOXYLIC ACID 98%
5-Methylisoxazole-4-carboxylic acid, 98+% | [EINECS(EC#)]
1312995-182-4 | [Molecular Formula]
C5H5NO3 | [MDL Number]
MFCD00955655 | [Molecular Weight]
127.1 | [MOL File]
42831-50-5.mol |
| Chemical Properties | Back Directory | [Appearance]
Cream to brown Solid | [Melting point ]
144-148 °C(lit.) | [Boiling point ]
308.3±22.0 °C(Predicted) | [density ]
1.348±0.06 g/cm3(Predicted) | [storage temp. ]
Sealed in dry,Room Temperature | [solubility ]
DMSO (Slightly), Methanol (Slightly) | [form ]
Solid | [pka]
2.85±0.25(Predicted) | [color ]
White to Pale Brown | [Usage]
Herbicidal activities towards Digitaria ciliaris | [BRN ]
116000 | [CAS DataBase Reference]
42831-50-5(CAS DataBase Reference) |
| Safety Data | Back Directory | [Hazard Codes ]
Xi,F | [Risk Statements ]
R36/37/38:Irritating to eyes, respiratory system and skin .
R37/38:Irritating to respiratory system and skin .
R36:Irritating to the eyes.
R10:Flammable. | [Safety Statements ]
S22:Do not breathe dust .
S26:In case of contact with eyes, rinse immediately with plenty of water and seek medical advice .
S36/37/39:Wear suitable protective clothing, gloves and eye/face protection .
S36:Wear suitable protective clothing .
S16:Keep away from sources of ignition-No smoking . | [WGK Germany ]
3
| [Hazard Note ]
Irritant | [HazardClass ]
IRRITANT | [HS Code ]
29349990 |
| Hazard Information | Back Directory | [Chemical Properties]
Cream to brown Solid | [Uses]
5-Methylisoxazole-4-carboxylic Acid (Leflunomide EP Impurity D) is an intermediate for synthesis of Leflunomide (L322750). Herbicidal activities towards Digitaria ciliaris. | [Uses]
An intermediate for synthesis of Leflunomide (L322750). Herbicidal activities towards Digitaria ciliaris | [Flammability and Explosibility]
Nonflammable | [Synthesis]
Example 4 Preparation of 5-methylisoxazole-4-carboxylic acid
To a two-necked flask equipped with a mechanical stirrer and a horizontal condenser for distillation were added 40.0 g of crude ethyl 5-methyl-4-isoxazolecarboxylate and 44 g of 60% sulfuric acid solution. The mixture was heated to 85°C while the ethanol generated from the reaction was continuously distilled. After 4 hours of reaction, thin layer chromatography (TLC) analysis showed complete disappearance of spots of ester compounds. After cooling the reaction mixture to room temperature, the solid product (16.5 g) was collected by filtration. The filtrate was retained for a second product collection at room temperature. The resulting crude acid was dissolved in 60 mL of 2% acetic acid-toluene mixed solvent and crystallized to give 5-methylisoxazole-4-carboxylic acid (9.5 g) of about 99.9% purity. The crystallized mother liquor was retained for subsequent batch processing. The crystallization process was performed as follows: the crude acid was added to 2% acetic acid-toluene solvent mixture and heated for 30 minutes until dissolved. Separate and remove the brown oil from the bottom of the flask. The upper clear organic phase was carefully transferred to another container and left to crystallize. | [References]
[1] Patent: US2003/139606, 2003, A1
[2] Letters in Drug Design and Discovery, 2016, vol. 13, # 9, p. 912 - 920
[3] Journal of Heterocyclic Chemistry, 1991, vol. 28, # 2, p. 453 - 457
[4] Yakugaku Zasshi, 1959, vol. 79, p. 836
[5] Chem.Abstr., 1960, p. 1493 |
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