5H-Pyrazolo[4,3-c]pyridine-5-carboxylic acid, 3-amino-2-(4-fluoro-3,5-dimethylphenyl)-2,4,6,7-tetrahydro-4-methyl-, 1,1-dimethylethyl ester, (4S)-

China [CN]

Formal Chinese Name: (4S)-3-Amino-2-(4-fluoro-3,5-dimethylphenyl)-4-methyl-2,4,6,7-tetrahydro-5H-pyrazolo[4,3-c]pyridine-5-carboxylic acid tert-butyl ester

Molecular Formula (Derived): C₂₁H₂₇FN₄O₂ (Derived from the structure: heterocyclic core + fluorinated aryl group + methyl group + tert-butyl ester, containing 1 F, 4 N, and 2 O)

Molecular Weight (Derived): 386.47 (Used for molar concentration calculations and product quantification; the tert-butyl ester protecting group increases the molecular weight)

Core Use: A key intermediate in the synthesis of heterocyclic drug active pharmaceutical ingredients, mainly used in the preparation of kinase inhibitors, antiepileptic drugs, or central nervous system drugs containing the pyrazolo[4,3-c]pyridine core.

Key Structural Features: 1. Contains a 5H-pyrazolo[4,3-c]pyridine double nitrogen heterocycle (the drug active core); 2. Has a **(4S) chiral center** + fluorinated aryl group, resulting in a highly customized structure; 3. The carboxylic acid is protected by a tert-butyl ester, and the amino group is a free active site; 4. The core is in a tetrahydro-reduced state, which is more stable than the aromatic state.

Key Physicochemical Properties (Derived): 1. Appearance: White to off-white crystalline powder (common form for heterocyclic ester intermediates); 2. Solubility: Slightly soluble in water, readily soluble in organic solvents such as dichloromethane, tetrahydrofuran, and ethyl acetate (tert-butyl ester and fluorinated aryl group reduce water solubility); 3. Stability: Stable under normal temperature, sealed, and dry storage conditions; avoid strong acids (tert-butyl ester is easily deprotected), strong bases, and oxidizing agents (amino group is easily oxidized); 4. Melting Point: Expected 160~180℃ (heterocycle + ester group + chiral center, moderate melting point)

Core Quality Indicators (Suggested): 1. Chiral Purity (ee value): ≥99% ((4S) 1. Configuration (key indicator affecting the optical activity of downstream drugs); 2. Chemical purity (HPLC): ≥98.5%; 3. Moisture content: ≤0.5%; 4. Tert-butyl ester protection rate: ≥99% (to avoid deprotection impurities)