Synthesis of [ChCl][ZnCl2] 2 ionic liquid
1 mmol of choline chloride salt and 2 mmol of ZnCl2 were poured into a 10 ml flask and the flask was put into
the oil bath over 100 °C temperature and mixture was allowed to melt, then a magnetic stirrer was placed into the
flask and the mixture stirred gently till a transparent [ChCl][ZnCl 2]2 ionic liquid was formed. IR (KBr): 3550,
3500, 1600, 1500, 1100, 980, 970, 900 cm-1. Anal. Calcd. for [ChCl][ZnCl2]2: C, 14.57; H, 3.42; N, 3.40. Found:
C, 14.70; H, 3.55; N, 3.48.
Synthesis of [H-NMP]HSO4 ionic liquid
Dry dichloromethane (10 ml) and 0.96 ml (10 mmol) of N-methyl-2-Pyrrolidone (NMP) were added to a 25
ml flask and the flask was placed in an ice bath on a magnetic stirrer and at the same time 0.53 ml (10 mmol) of
concentrated sulfuric acid, was gradually added to the mixture. After adding the acid, the resulting mixture stirred
for three hours at ambient temperature and then CH2Cl2 was removed by evaporation and the product was
completely dried by vacuum pumps. This acidic ionic liquid could be recycled after using in different reactions.
In each reaction after filtering the product, to retrieve the ionic liquid, the aqueous phase containing ionic liquid
was washed three times (each time 10 ml) with dichloromethane to be separated from the organic impurities. Next,
the water was evaporated and the recycled ionic liquid was dried under the vacuum at 65 °C for 2 hours and was
reused. IR (KBr): 2700-3600, 1693, 1671, 1483, 1287, 1229, 1175, 1064, 1016, 881, 845, 591 cm -1. 1H NMR (400
MHz, DMSO-d6): δ= 1.86 (m, 2H, CH2), 2.16 (t, 2H, CH2), 2.66 (s, 3H, CH3), 3.27 (t, 2H, CH2), 9.15 (s, 4H).
The general method for the preparation of pyrano[2,3-c]pyrazoles in the presence of [ChCl][ZnCl2] 2 ionic liquid
under solvent-free conditions
1.25 mmol of hydrazine hydrate, 1 mmol of ethyl acetoacetate, 1 mmol of malononitrile, 1 mmol of the
required aldehyde and 0.15 mmol of [ChCl][ZnCl2]2 ionic liquid were added to a flask. The reaction mixture was
put in 90 °C temperature and stirred by a magnetic stirrer. Progress of the reaction was followed by TLC with a
mixture of cyclohexane and ethyl acetate, by 3 to 1 ratio, respectively. In most cases, the reaction was performed
in about 10 minutes. For some cases, products were obtained with high purity and did not require further
purification. If necessary, products were further purified by column chromatography using silica gel or
recrystallization of ethanol was done.
The general method for the preparation of pyrano[2,3-c]pyrazoles in the presence of [H-NMP]HSO4 ionic liquid
under solvent-free conditions
1.25 mmol of hydrazine hydrate, 1 mmol of ethyl acetoacetate, 1 mmol of malononitrile, 1 mmol of the
required aldehyde and 0.12 mmol of [H-NMP]HSO4 ionic liquid were added into a flask. The reaction mixture
was put in 90 °C temperature and stirred by a magnetic stirrer. Progress of reaction was followed by TLC using a
mixture of cyclohexane and ethyl acetate solvents by 3 to 1 ratio, respectively. In most cases, the reaction was
performed in about 4 minutes. In some cases, products were obtained with high purity and did not require further
purification. If necessary, products were further purified by column chromatography using silica gel.
Spectroscopic data for several compounds
5b Melting point: 174-176 °C. IR (KBr, cm-1): 3469, 3239, 2968, 2928, 2188, 1639, 1624, 1595, 1509, 1490,
1428, 1395, 1170, 1065 cm-1. 1H NMR (400 MHz, DMSO-d6): δ= 1.87 (s, 3H, CH3), 4.92 (s, 1H, CH), 7.04 (s,
2H, NH2), 7.18-7.20 (d, J = 8.4 Hz, 2H, ArH), 7.36-7.38 (d, J = 8.4 Hz, 2H, ArH), 12.35 (s, 1H, NH).
5c Melting point: 173-175 °C. IR (KBr, cm-1): 3477, 3235, 2970, 2925, 2191, 1644, 1626, 1592, 1512, 1488,
1433, 1398, 1175, 1067 cm-1. 1H NMR (400 MHz, DMSO-d6): δ= 1.79 (s, 3H, CH3), 4.64 (s, 1H, CH), 6.94 (s,
2H, NH2), 7.58-7.60 (d, J= 8.4 Hz, 2H, ArH), 7.90-7.92 (d, J = 8.4 Hz, 2H, ArH), 12.15 (s, 1H, NH).
5d Melting point: 191-193 °C. IR (KBr, cm-1): 3482, 3235, 3114, 2227, 2187, 1641, 1593, 1493, 1408, 1159, 1053
cm-1. 1H NMR (400 MHz, DMSO-d6): δ= 1.79 (s, 3H, CH3), 4.75 (s, 1H, CH), 7.03 (s, 2H, NH2), 7.38-7.40 (d, J
= 8.0 Hz, 2H, ArH), 7.79-7.81 (d, J = 8.0 Hz, 2H, ArH), 12.19 (s, 1H, NH). 13C NMR (400 MHz, DMSO-d6): δ=
12.89, 20.97, 59.98, 109.58, 115.65, 116.80, 117.29, 129.83, 132.12, 135.20, 139.22, 139.39, 176.23.
5g Melting point: 225-227 °C. IR (KBr, cm-1): 3465, 3229, 2935, 2203, 1616, 1509, 1454, 1215, 1121 cm -1. 1H
NMR (400 MHz, DMSO-d6): δ= 1.91 (s, 3H, CH3), 4.81 (s, 1H, CH), 6.33 (d, J= 2.0 Hz, 1H , ArH), 6.39-6.41
(dd, J= 8.4 Hz, J= 2.0 Hz, 1H , ArH), 6.93 (s, 2H , NH2), 7.41-7.43 (d, J= 8.4 Hz, 1H , ArH), 8.78 (s, 1H, OH),
10.23 (s, 1H, OH), 11.41 (s, 1H, NH).
5i Melting point: 214-216 °C. IR (KBr, cm-1): 3375, 3306, 3163, 2184, 1648, 1610, 1592, 1488, 1402, 1153, 1078
cm-1. 1H NMR (400 MHz, DMSO-d6): δ= 2.11 (s, 3H, CH3), 4.92 (s, 1H, CH), 6.35 (s, 2H, NH2), 7.30-7.65 (m,
2H, ArH), 7.80-7.95 (m, 2H, ArH) 10.25 (s, 1H, OH), 11.43 (s, 1H, NH).