Table 3.

Scope of lignin β-O-4 model compounds and aminopyridine for the synthesis of imidazo[1,2-a]pyridines

Entrya	Sub.1	Sub.2		3 Yield (%)	4 Yield (%)	Entry	Sub.1	Sub.2	3 Yield (%)	4 Yield (%)
1						8	1a			4a 96%
2			2a			9	1a			4a 96%
3			2a			10	1a			4a 97%
4			2a			11	1a			4a 96%
5			2a			12	1a			4a 95%
6			2a			13	1a			4a 96%
7			2a			14	1a			4a 95%

^aReaction conditions: for step 1: 1a (0.2 mmol), 5 wt% Pd/C (5 mol%), NaBH₄ (10 mol%) in water (0.5 mL), toluene (1.5 mL), 140°C, t = 2 h. Forstep 2: 2a (0.8 mmol), I₂ (0.35 mmol), NH₄HCO₃ (0.4 mmol), 140°C, t = 15 h. Yield refers to isolated yield.