Yield:642459-26-5 35 %

Reaction Conditions:

Stage #1: cyclohexylaminewith potassium carbonate in N,N-dimethyl-formamide at 20;
Stage #2: 2,6-dichloropyrazine in N,N-dimethyl-formamide at 20;

Steps:

2-2-3 6-chloro-N-cyclohexylpyrazine-2-amine [6-chloro-N-cyclohexylpyrazin-2-amine] Synthesis: compound (2c)

cyclohexylamine (5.0 mmol, 0.58 mL) and K2CO3 (6.7 mmol, 0.93 g) were added to 5.0 mL of DMF and the mixture was stirred at room temperature for 30 minutes. 2,6-dichloropyrazine (3.4 mmol, 0.50 g) was added and the reaction mixture was stirred overnight at room temperature and then the solvent was removed from the vacuum. The residue was treated with DCM and filtered using cellite, then the filtrate was collected and the solvent was removed from the vacuum. The final residue was purified by silica gel chromatography using 40: 1 DCM / EA to obtain 0.25 g (35%) of the title compound (2c).

References:

WO2023/17937,2023,A1 Location in patent:Paragraph 91-93; 111-114