Triethylamine → Ethyl 5-methyl-7-(3-methylbenzo[b]thiophen-2-yl)-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate

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Reaction Steps

The 5-aminotetrazole (850 mg; 10.0 mmole) was dissolved in hot ethanol (25 ml) with triethylamine (1.8 mmole; 0.25 ml). When all solids were dissolved (about ten minutes of heating at 82° C.), 3-methyl-2-benzothiophenecarboxaldehyde (1.76 g; 10.0 mmole) was added followed by ethylacetoacetate (1.28 ml; 10.0 mmole). The clear solution was maintained at reflux for 15 h. At which time a white precipitate had filled the flask and the mixture was cooled to room temperature where it was filtered and the material washed with ethanol then ethyl ether to provide the desired product (1.42 g; 41%) as a white powder. 1H NMR (400 MHz; CDCl3) δ 11.2 (bs, 1H); 7.73 (d, 1H, J=7.8 Hz); 7.69 (d, 1H, J=7.8 Hz); 7.39 (ddd, 1H, J=7.0, 7.0, 0.78 Hz); 7.32 (ddd, 1H, J=8.2, 7.0, 1.5 Hz); 4.17-4.05 (m, 2H); 2.71 (s, 3H); 2.69 (s, 3H); 1.14 (at, J=7.0 Hz). LC MS shows MH+ at 356 and 2 MH+ at 711.

Provenance & Evidence