Yields of compound 4a–i depending on the substituent (Ar) in the starting aldehydes.
| Compounds | Substituent Ar | Yield 4a, % | Compounds | Substituent Ar | Yield 4a, % |
|---|---|---|---|---|---|
| 4a | 4-F-C6H4 | 67 | 4f | 3,4-(CH3O)2–C6H3 | 53 |
| 4b | 4-Cl-C6H4 | 61 | 4g | 4-CH3-C6H4 | 63 |
| 4c | 3-F-C6H4 | 58 | 4h | 4-(CH3)2N–C6H4 | 44 |
| 4d | 4-CF3-C6H4 | 68 | 4i | 1,3-Benzodioxol-5-yl | 73 |
| 4e | 4-(CH3O)–C6H4 | 59 |
The given yields for compounds 4a–i were obtained by method B.