Table 2 The scope of synthesis of DHPP 6a-p derivatives under optimized conditions using the CS-g-PAN/Fe3O4 nanocatalyst (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 b

Entry

R

Productb

Time (min)

Yieldc (%)

M.p. (oC)

M.p. (oC) (Lit.)

Ref

1

4-Cl

6a

10

95

216–218

216–219

81

2

2-Cl

6b

10

95

243–245

245–246

82

3

2,4-Cl2

6c

10

95

230–234

231–233

83

4

4-Me

6d

25

95

195–200

196–198

84

5

4-OMe

6e

20

91

210–212

209–212

50

6

2-OMe

6f

20

90

249–253

251–253

10

7

3-OH

6g

20

89

254–256

253–256

85

8

4-OH

6h

20

91

225–226

224–226

86

9

4-Br

6i

20

92

217–220

218–220

87

10

4-F

6j

20

94

170–172

168–170

88

11

3-NO2

6k

30

98

214–215

213–215

89

12

4-NO2

6l

35

89

251–253

250–252

90

13

4-CN

6m

32

90

213–215

212–214

87

14

2-Furyl

6n

36

79

227–229

227–229

91

15

2-Thienyl

6o

36

79

250–252

251–253

83

16

3-Pyridyl

6p

39

84

214–215

216–217

92

  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 malononitrile (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. All compounds are known and their structures were established from their spectral data and melting points as compared with literature values. cYields refer to the isolated products.
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