Comparative study of the present method and some other reported methods for synthesis of 4H-pyrimido[2,1-b]benzothiazole derivatives.
| Ent. | Solvent | Catal. | Tem. (°C) | Time (h) | Yielda (%) | Ref. |
|---|---|---|---|---|---|---|
| 1 | CH3OH | Acetic acid (20 mol%) | 65 | 18 | 62 | 20 |
| 2 | EG | TBAHS (30 mol%)b | 120 | 2 | 72 | 17 |
| 3 | HOAc | Chitosan (0.080 g) | 70 | 1.6 | 93 | 18 |
| 4 | — | TMGT (0.080 g)c | 100 | 5 | 53 | 16 |
| 5 | — | AlCl3 (10 mol%) | 65 | 1.2 | 97 | 22 |
| 6 | — | Fe3O4@NCs/TiCl (0.03 g) | 70 | 0.6 | 96 | 23 |
| 7 | — | Fe3O4@ nano-cellulose/Cu(ii) (0.03 g) | 80 | 0.5 | 97 | This work |
a
Isolated yield.
b
Tetrabutylammonium hydrogen sulfate.
c
1,1,3,3-N,N,N′,N′-Tetramethylguanidinium trifluoroacetate.