Table 1 Optimizing of different parameters for the model reaction in the synthesis of 6a catalyzed by the CS-g-PAN/Fe3O4 nanoparticles (1)a.

From: Preparation of magnetic decorated polyacrylonitrile-grafted chitosan as a new bio-inspired nanocatalyst for the synthesis of dihydropyrano[2,3-c]pyrazole and 2-amino-3-cyano-4H-pyran derivatives

scheme a

Entry

Catalyst

Catalyst loading (mg)

Solvent

Temp (oC)

Time (min)

Yieldb(%)

1

-

-

-

r.t.

120

Trace

2

-

-

-

80

120

Trace

3

-

-

CH3CN

Reflux

120

Trace

4

CS-g-PAN/Fe3O4

10

-

r.t.

30

< 50

5

CS-g-PAN/Fe3O4

10

EtOH

r.t.

20

72

6

CS-g-PAN/Fe3O4

10

EtOH

80

20

88

7

CS-g-PAN/Fe3O4

10

H2O

Reflux

20

< 60

8

CS-g-PAN/Fe3O4

10

EtOH/H2O (1:1)

80

10

97

9

CS-g-PAN/Fe3O4

5

EtOH/H2O (1:1)

80

15

85

10

CS-g-PAN/Fe3O4

8

EtOH/H2O (1:1)

80

10

92

11

CS-g-PAN/Fe3O4

10

EtOH/H2O (1:1)

r.t.

10

74

12

CS-g-PAN/Fe3O4

10

EtOH/H2O (1:1)

Reflux

10

90

13

Fe3O4

10

EtOH/H2O (1:1)

80

20

N.R.

14

Chitosan

10

EtOH/H2O (1:1)

80

20

48

15

CS-g-PAN/Fe3O4

40

EtOH

Reflux

10

94

  1. Significant values are in [bold].
  2. aReaction conditions: ethyl acetoacetate (2, 1.0 mmol), hydrazine hydrate (3, 1.0 mmol), aldehyde (5a, 1.0 mmol) and malononirile (4, 1.0 mmol), in the presence of CS-g-PAN/Fe3O4 nanomaterial (1) were added to the solvent (2.0 ml) unless otherwise stated. bIsolated yields.
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