Synthesis and Application of Nanocrystalline-Cellulose-Supported Acid Ionic Liquid Catalyst in Pechmann Reaction

Table 4

Preparation of coumarins using NCC-supported sulfonic acid ionic liquid^a.

Entry	Reactant	Product	Time	Yield (%)^b	m.p (°C)	Lit.^c
1			24 (h)	trace	77–79	79–81 [15]
2			20 (min)	95	185	182–184 [14]
3			6.5 (h)	60	244	241-242 [15]
4			6 (h)	20	130–132	130-131 [16]
5			5 (h)	80	161-162	158–160 [14]
6			1.5 (h)	75	221–224	220–224 [17]
7			20 (min)	85	230–233	234-235 [14]
8			5 (h)	94	154–156	153–155 [14]
9			10 (h)	40	180–182	182-183 [18]
10			24 (h)	N.R	—	—
11			18 (min)	98	172–175	170–172 [16]

aThe reactions were performed in the absence of solvent at 80°C. ^bIsolated yields. ^cThe products were characterized by comparison of their spectroscopic and physical data with reference samples synthesized by the reported procedure.