5-CHLORO-PYRAZINE-2-CARBOXYLIC ACID

5-Chloropyrazine-2-carboxylic acid (CAS 36070-80-1) is a strategically bifunctional pyrazine scaffold engineered for heterocyclic diversification, pharmaceutical intermediate synthesis, and agrochemical development. This molecule integrates an electron-deficient pyrazine core—a six-membered aromatic diazine ring with nitrogen atoms at para positions (1,4)—with a chlorine substituent at the C5 position and a carboxylic acid group at the C2 position. The C2-carboxylic acid moiety serves as a versatile handle for amide coupling, esterification, or salt formation, while the C5-chloro handle is activated by the adjacent ring nitrogen, enabling efficient nucleophilic aromatic substitution (SNAr) or Pd-catalyzed cross-coupling (Suzuki, Buchwald-Hartwig). This dual-functionality architecture enables orthogonal derivatization strategies, making it particularly valuable for constructing fused heterocycles (pyrazino-fused systems), kinase inhibitor cores, and agrochemical actives where the chloroacid-pyrazine motif balances electron-deficient character with synthetic flexibility. Compared to its amino analog (CAS 40155-43-9), the chloro substituent offers enhanced metabolic stability and distinct reactivity for late-stage functionalization. Manufactured with purity ≥98% under controlled conditions, it supports drug discovery programs requiring modular access to differentially functionalized electron-deficient heterocycles.

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Product Name	5-Chloropyrazine-2-carboxylic acid
CAS Number	36070-80-1
Chinese Name	5-氯吡嗪 -2-羧酸
Synonyms	5-Chloro-2-pyrazinecarboxylic acid; Pyrazine-2-carboxylic acid, 5-chloro-; C₅H₃ClN₂O₂ heterocycle; 5-CPA
Chinese Synonyms	5-氯 -2-吡嗪羧酸; 5-氯吡嗪 -2-甲酸; 氯吡嗪羧酸; 5-位氯 -2-位羧酸吡嗪
Molecular Formula	C₅H₃ClN₂O₂
Molecular Weight	158.54 g/mol
Purity	≥ 98% (HPLC area normalization)
Product Category	Pharmaceutical Intermediates / Pyrazine Derivatives / Halogenated Carboxylic Acids
Appearance	White to Light Yellow to Light Tan Crystalline Powder
Melting Point	206-210°C (decomposition, literature reference recommended)
pKa	~2.0-3.0 (carboxylic acid, estimated)
Storage Conditions	Store in a cool, dry, well-ventilated area away from light and moisture. Keep container tightly closed under inert atmosphere (nitrogen). Protect from strong bases to avoid premature chloride displacement or decarboxylation.
Shelf Life	24 months under recommended storage conditions
Packaging	100mg/vial, 500mg/vial, 1g/bottle, 5g/bottle, or customized according to customer requirements
Applications	Kinase inhibitor synthesis, heterocyclic library construction (pyrazino-fused systems), agrochemical intermediate synthesis, amide coupling for drug conjugates, ligand synthesis for coordination chemistry, sequential functionalization via orthogonal Cl/COOH reactivity
Reactivity	Suitable for nucleophilic aromatic substitution (C5-Cl displacement), carboxylic acid activation (EDC/HATU), esterification, heterocyclic fusion, electrophilic aromatic substitution at C3/C6, and Pd-catalyzed cross-coupling
Special Note	✅ Bifunctional Chloroacid Scaffold—C2-COOH for coupling, C5-Cl for substitution/cross-coupling. Electron-deficient pyrazine core provides unique binding geometry vs. phenyl analogs. Distinct from amino analog (CAS 40155-43-9) by metabolic stability. Part of our pyrazine building block series.