Table 2. Effect of Solvents in Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones/thiones (4–9).
solvent | time (min) | yield (%)a |
---|---|---|
DCM | 30 | 39 |
DMF | 30 | 46 |
THF | 30 | 52 |
CH3CN | 30 | 57 |
CHCl3 | 30 | 52 |
MeOH | 20 | 79 |
ACOH | 20 | 76 |
EtOH | 6 | 90 |
H2O | 6 | 89 |
H2O/EtOH | 3 | 98 |
Isolated yields based on 4, 1 (1 mmol), 2a (1.5 mmol), and 3a (1 mmol) in a mixture of water and ethanol (3:1 ratio) by microwave irradiation condition, 3 min.