4-Methylisothiazole-5-carboxylic acid CAS 15901-61-8

Purity 97%+In StockPharmaceutical Standards
CAS No.15901-61-8
Molecular FormulaC5H5NO2S
Molecular Weight143.16 g/mol
CategoryPharmaceutical Standards / API Standards
AvailabilityIn Stock

Chemical Structure

4-Methylisothiazole-5-carboxylic acid CAS 15901-61-8 chemical structure

Description

Owing to an amide group, a sulfone group, a carboxylic acid group, a hydroxyl group, an ether linkage, 4-Methylisothiazole-5-carboxylic acid is typically off-white to pale yellow liquid. Its solid-state physicochemical attributes — including a molecular weight of 143.16 g/mol — guide the selection of appropriate sample preparation and analytical techniques. Nitrogen-containing functional groups confer excellent ionization efficiency in positive-ion electrospray (ESI) mode, making the compound well suited to LC-MS/MS analysis.

4-Methylisothiazole-5-carboxylic acid (CAS 15901-61-8) is a high-purity analytical reference standard with the molecular formula C5H5NO2S and a molecular weight of 143.16 g/mol.

This reference standard is suitable for quantitative analysis on major chromatographic platforms including HPLC, GC, LC-MS/MS, and GC-MS, serving as an external calibration standard or a system suitability test reference material.

The assigned purity is verified by mass-balance and quantitative NMR (qNMR) approaches, with the expanded uncertainty reported at a 95% confidence level (k=2). Batch homogeneity and stability are independently assessed for every lot.

Physical & Chemical Properties

Molecular FormulaC5H5NO2S
Molecular Weight143.16 g/mol
Purity97%+
StorageStore at 2-8°C, protect from light
Solubility (reference)Soluble in methanol, acetonitrile, DMSO, water (slightly soluble)
StabilityMay oxidize slowly on prolonged air exposure; Light-sensitive; avoid direct strong light
Degree of Unsaturation (DBE)4.0
UV AbsorptionUV-absorbing
CAS Registry Year (est.)1961
Nitrogen Atoms1
Sulfur Atoms1

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