The 5-Methyl-4-isoxazolecarboxylic acid, with the CAS registry number 42831-50-5, is also known as 5-Methylisoxazole-4-carboxylic acid. It belongs to the product categories of 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. This chemical's molecular formula is C₅H₅NO₃ and molecular weight is 127.0981. Its IUPAC name is called 5-methyl-1,2-oxazole-4-carboxylic acid. This chemical can be used as medicine intermediates of Leflunomide. The product should be sealed and stored in cool and dry place.

Physical properties of 5-Methyl-4-isoxazolecarboxylic acid: (1)ACD/LogP: 0.22; (2)ACD/LogD (pH 5.5): -2.32; (3)ACD/LogD (pH 7.4): -2.92; (4)ACD/BCF (pH 5.5): 1; (5)ACD/BCF (pH 7.4): 1; (6)ACD/KOC (pH 5.5): 1; (7)ACD/KOC (pH 7.4): 1; (8)#H bond acceptors: 4; (9)#H bond donors: 1; (10)#Freely Rotating Bonds: 1 ; (11)Index of Refraction: 1.514; (12)Molar Refractivity: 28.39 cm³; (13)Molar Volume: 94.2 cm³; (14)Surface Tension: 53.7 dyne/cm; (15)Density: 1.348 g/cm³; (16)Flash Point: 140.3 °C; (17)Enthalpy of Vaporization: 57.97 kJ/mol; (18)Boiling Point: 308.3 °C at 760 mmHg; (19)Vapour Pressure: 0.000297 mmHg at 25°C.

Preparation: this chemical can be prepared by 5-methyl-isoxazole-4-carboxylic acid ethyl ester. This reaction will need reagent aqueous H₂SO₄.

Uses of 5-Methyl-4-isoxazolecarboxylic acid: it can be used to produce 5-methyl-isoxazole-4-carbonyl chloride at temperature of 70 °C. This reaction will need reagent SOCl₂ with reaction time of 1 hour. The yield is about 96%.

When you are using this chemical, please be cautious about it as the following:
This chemical may cause inflammation to the skin or other mucous membranes. It is irritating to eyes, respiratory system and skin. In case of contact with eyes, you should rinse immediately with plenty of water and seek medical advice. Whenever you will contact it, please wear suitable protective clothing, gloves and eye/face protection.

You can still convert the following datas into molecular structure:
(1)Canonical SMILES: CC1=C(C=NO1)C(=O)O
(2)InChI: InChI=1S/C5H5NO3/c1-3-4(5(7)8)2-6-9-3/h2H,1H3,(H,7,8)
(3)InChIKey: VQBXUKGMJCPBMF-UHFFFAOYSA-N