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Methyl 5-bromo-1H-pyrazole-3-carboxylate
Methyl 5-bromo-1H-pyrazole-3-carboxylate (CAS 1328893-17-9) is a strategically brominated pyrazole ester engineered for regioselective cross-coupling applications in medicinal chemistry and agrochemical development. This molecule integrates three orthogonal functional elements: a C5-bromo substituent serving as a privileged handle for Pd-catalyzed transformations (Suzuki, Buchwald-Hartwig, Sonogashira), a C3-methyl ester enabling hydrolysis to the free acid or amide coupling, and a 1H-pyrazole core that provides dual hydrogen-bond donor/acceptor capability for enhanced target binding. The electron-deficient bromine at C5—activated by the adjacent ring nitrogens—facilitates efficient nucleophilic displacement or metal-catalyzed functionalization, while the ester moiety offers modular access to diverse carboxylate derivatives. This intermediate is particularly valuable for constructing fused heterocyclic systems (pyrazolo[1,5-a]pyrimidines), kinase inhibitor cores targeting ATP-binding pockets, and agrochemical actives where the 5-bromopyrazole motif enables rapid SAR exploration. Manufactured with purity ≥98% under controlled conditions, it supports drug discovery programs requiring modular diversification of nitrogen-rich heterocyclic architectures.
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| Product Name | Methyl 5-bromo-1H-pyrazole-3-carboxylate |
| CAS Number | 1328893-17-9 |
| MDL Number | MFCD23701497 |
| EINECS Number | 814-396-5 |
| Chinese Name | 5-溴-1H-吡唑-3-羧酸甲酯 |
| Synonyms | Methyl 5-bromopyrazole-3-carboxylate; 1H-Pyrazole-3-carboxylic acid, 5-bromo-, methyl ester; 5-Bromo-3-methoxycarbonylpyrazole; Methyl 3-bromo-1H-pyrazole-5-carboxylate |
| Chinese Synonyms | 5-溴吡唑-3-羧酸甲酯; 5-溴-3-甲氧羰基吡唑; 5-溴-1H-吡唑-3-甲酸甲酯; 5-溴-1H-吡唑-3-羧酸甲酯 |
| IUPAC Name | methyl 5-bromo-1H-pyrazole-3-carboxylate |
| Molecular Formula | C₅H₅BrN₂O₂ |
| Molecular Weight | 205.01 g/mol |
| Exact Mass | 203.95344 Da |
| Purity | ≥95% – 98% (HPLC) |
| Appearance | White to Off-white Solid |
| Melting Point | 90 – 92 °C |
| Boiling Point | 329.5 ± 22.0 °C at 760 mmHg (Predicted) |
| Density | 1.781 ± 0.06 g/cm³ (Predicted) |
| Flash Point | 153.1 ± 22.3 °C (Predicted) |
| pKa | 7.92 ± 0.10 (Predicted) |
| LogP | 1.4 (XLogP3-AA) |
| Storage Conditions | Store under inert atmosphere (nitrogen or argon) at 2-8°C recommended for long-term stability. Keep container tightly closed and protected from light and moisture . |
| Shelf Life | 24 months under recommended storage conditions |
| Packaging | 100 mg, 250 mg, 500 mg, 1 g, 5 g, 10 g, 25 g, 100 g, or customized upon request |
| GHS Classification | Warning. H302 (Harmful if swallowed), H315 (Causes skin irritation), H319 (Causes serious eye irritation), H332 (Harmful if inhaled), H335 (May cause respiratory irritation) |
| Product Category | Pharmaceutical Intermediates; Pyrazole Derivatives; Brominated Heterocycles; Building Blocks; Cross-Coupling Reagents |
