Entry

Solvent

Yield (%)^a*

Yield (%)^b*

1

EtOH

24

51

2

CH₃CN

31

63

3

Water

23

45

4

DMSO

15

30

5

DMF

25

45

6

THF

32

50

7

toluene

trace

trace

8

Water/THF (v/v = 1:1)

9

39

9

Water/EtOH (v/v = 1:1)

29

56

10

Water/DMSO (v/v = 1:1)

40

70

11

Water/DMF (v/v = 2:1)

45

88

12

Water/DMF (v/v = 1:1)

62

96

13

Water/Acetonitrile (v/v = 1:1)

46

76