5-Isoquinolinesulfonic acid synthesis

Yield:27655-40-9 85%

Reaction Conditions:

with thionyl chloride in N,N-dimethyl-formamide for 2 h;Reflux;

Steps:

4.1.2 General procedure for synthesis of compound 6o-6p
The synthetic procedure of compound 3i was conducted according to the reported procedures.^56,57 To a 100mL round-bottomed flask add 5-isoquinoline sulfonic acid (2.10g, 10mmol), 25mL thionyl chloride, 1mL dimethylformamide, the resulting mixture was refluxed for 2h. After that, SOCl₂ was removed by rotary evaporation, the residue was suspended in CH₂Cl₂, filtered, and washed with CH₂Cl₂ (2×25mL). The precipitate was collected and dried in vacuum to give crude crystalline isoquinoline-5-sulfonyl chloride hydrochloride, yield 85% (2.25g). To a 100mL round-bottomed flask add isoquinoline-5-sulfonyl chloride hydrochloride (2.0g, 7.6mmol) and 20mL ice-cold deionized water. The mixture was added slowly equimolar NaHCO₃ (0.64g), the resulting solution was extracted twice with CH₂Cl₂ (2×20mL). Organic layer was dried over anhydrous sodium sulfate and added dropwise to a 25mL CH₂Cl₂ solution of ethylenediamine (1.37g, 22.8mmol) at 0°C. The reaction continued for 1h at room temperature, washed with deionized water to remove the excess ethylenediamine, and evaporated off. The residue was recrystallized from ethanol to give pure 3i, yield 55%,

References:

Jin, Feng;Gao, Dan;Wu, Qin;Liu, Feng;Chen, Yuzong;Tan, Chunyan;Jiang, Yuyang [Bioorganic and Medicinal Chemistry,2013,vol. 21,# 18,p. 5694 - 5706]

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