1-Naphthaldehyde → Ethyl 5-isopropyl-7-(naphthalen-1-yl)-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate

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Reaction Steps

The 5-aminotetrazole (850 mg; 10.0 mmole) is dissolved in hot ethanol (25 ml) with triethylamine (1.8 mmole; 0.25 ml). When all solids are dissolved (about ten minutes of heating at 82° C.), 1-naphthaldehyde (1.36 ml; 10.0 mmole) is added followed by ethyl isopropylacetoacetate (1.60 ml; 10.0 mmole). The clear solution is maintained at reflux for 15 h. The ethanol is removed in vacuo and the residue is dissolved in ethyl acetate. The ethyl acetate phase is added to a separatory funnel and subsequently washed with 1M HCl, water, then brine. The organic phase is dried over MgSO4 and filtered. The organic phase is reduced in volume in vacuo to get an oil. A 1:1 mixture of ethyl acetate and hexanes was added to the viscous oil and stirred with a spatula to provide a precipitate. The solid was filtered to provide the product (0.700 g, 19%) as a white powder. 1H NMR (400 MHz; CDCl3) d 11.0 (bs, 1H); 7.88 (d, 1H, J=8.2 Hz); 7.82 (d, 1H, J=8.2 Hz); 7.70-7.36 (m, 5H); 4.5 (m, 1H); 3.92-3.80 (m, 2H); 1.55 (d, 3H, J=6.7 Hz); 1.40 (d, 3H, J=7.0 Hz); 0.74 (at, 3H, J=7.0 Hz). LC MS shows MH+ at 364 and 2 MH+ at 727.

Provenance & Evidence