3-Methylisothiazole-5-carboxylic acid CAS 66975-83-5
| CAS No. | 66975-83-5 |
| Molecular Formula | C5H5NO2S |
| Molecular Weight | 143.16 g/mol |
| Category | Pharmaceutical Standards / API Standards |
| Availability | In Stock |
Chemical Structure
Description
As a certified reference material (CRM), 3-Methylisothiazole-5-carboxylic acid meets the metrological traceability requirements of ISO/IEC 17025 laboratories. Batch-to-batch consistency is monitored via control charts to guarantee comparable assigned values across lots.
3-Methylisothiazole-5-carboxylic acid (CAS 66975-83-5), molecular formula C5H5NO2S and molecular weight 143.16 g/mol, is a CATO reference standard with documented purity and traceability.
3-Methylisothiazole-5-carboxylic acid (C5H5NO2S) contains an amide group, a sulfone group, a carboxylic acid group, a hydroxyl group, an ether linkage. The carboxyl group imparts weak acidity; these physicochemical properties determine the optimal preparation and storage of its standard solutions. Nitrogen-containing functional groups confer excellent ionization efficiency in positive-ion electrospray (ESI) mode, making the compound well suited to LC-MS/MS analysis.
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.
Physical & Chemical Properties
| Molecular Formula | C5H5NO2S |
| Molecular Weight | 143.16 g/mol |
| Purity | 97%+ |
| Storage | Store at 2-8°C, protect from light |
| Solubility (reference) | Soluble in methanol, acetonitrile, DMSO, water (slightly soluble) |
| Stability | May oxidize slowly on prolonged air exposure; Light-sensitive; avoid direct strong light |
| Degree of Unsaturation (DBE) | 4.0 |
| UV Absorption | UV-absorbing |
| CAS Registry Year (est.) | 1976 |
| Nitrogen Atoms | 1 |
| Sulfur Atoms | 1 |
Related Methylisothiazole Standards
- 5-Methylisothiazole-3-carboxylic acid (CAS 110632-59-2)
- 5-Methylisothiazole-4-carboxylic acid (CAS 1125409-67-7)
- 4-Methylisothiazole-3-carboxylic acid (CAS 1507952-32-0)
- 4-Methylisothiazole-5-carboxylic acid (CAS 15901-61-8)
- Methylisothiazole-5-carboxylate (CAS 15901-66-3)
- 3-Methylisothiazole-4-carboxamide (CAS 1259065-61-6)
- Methyl 3-methylisothiazole-5-carboxylate (CAS 15901-54-9)
- Methyl 5-methylisothiazole-4-carboxylate (CAS 15901-70-9)
Recommended Standards
- 3-MEthyl-4-nitrothiophene (CAS 39920-22-4)
- 4-(Hydroxymethyl)-1,3-thiazole-2-carbaldehyde (CAS 466686-75-9)
- 3-Methyl-2-nitrothiophene (CAS 32059-75-9)
- 4-Aminothiophene-3-carboxylic acid (CAS 26112-64-1)
- 6-(3-Nitrophenyl)pyridazin-3-ol (CAS 54558-01-9)
- 1,5-Dichloro-2-difluoromethoxy-3-fluorobenzene (CAS 1806328-57-3)
- 3-(5-Bromofuran-2-yl)benzyl acetate (CAS 89929-91-9)
- 2,3-Dihydro-1H-pyrrolo[2,3-b]pyridine (Hydrochloride) (CAS 1415564-47-4)
- Dichloro(η6-p-cymene)ruthenium (CAS 100928-22-1)
- 2-Amino-4-(4-chlorophenyl)-6-(2-methylpropyl)pyridine-3-carbonitrile (CAS 331828-45-6)
- 3-BROMO-5-METHOXYPYRIDINE 1-OXIDE (CAS 78156-39-5)
- Methyl (R)-3-amino-3-(4-chloro-3-fluorophenyl)propanoate (CAS 1213402-97-1)
- Quinolin-6(8aH)-one (CAS 344796-83-4)
- (Glu1)-Fibrinopeptide B (human) (CAS 103213-49-6)
Why CATO?
- ISO 17034 accredited reference material producer (CNAS + ANAB dual accreditation)
- 130,000+ catalog items in stock, COA supplied with every batch
- Worldwide shipping with full export documentation (HS code guidance available)
- Technical support: +86 18665070610 / Nicole.chen@cato-chem.com