Triphenylphosphine → 3-(7-cyano-1,2,3,4-tetrahydro-naphthalen-1-yl)-3H-imidazole-4-carboxylic acid isopropyl ester

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Reaction Steps

To a suspension of 7-cyano-1,2,3,4-tetrahydro-naphthalen-1-ol (0.298 g, 1.72 mmol) and isopropyl 4-imidazolecarboxylate (0.185 g, 1.204 mmol), which can be prepared as described in Example 1, in THF (10 mL) at 0° C. is added triphenylphosphine (0.451 g, 1.72 mmol), followed by diisopropyl azodicarboxylate (94%, 0.369 g, 1.72 mmol). After 1 hour the mixture is diluted with ethyl acetate and washed with water. The organic phase is dried over MgSO4, filtered and concentrated. The resulting residue is purified by silica gel chromatography (elution with hexanes-ethyl acetate mixtures) to give 3-(7-cyano-1,2,3,4-tetrahydro-naphthalen-1-yl)-3H-imidazole-4-carboxylic acid isopropyl ester; MS: (ESI) m/z 310.1 (M+H)+. The HCl salt of the title compound can be prepared by dissolution in diethyl ether followed by treatment with an excess of 1N HCl in diethyl ether. The resulting heterogeneous solution is concentrated to furnish the HCl salt of 3-(7-cyano-1,2,3,4-tetrahydro-naphthalen-1-yl)-3H-imidazole-4-carboxylic acid isopropyl ester; 1H NMR (400 MHz, MeOD) δ ppm 1.36 (d, J=6.1 Hz, 3 H), 1.39 (d, J=6.3 Hz, 3 H), 1.90-1.98 (m, 2 H), 2.29-2.33 (m, 2 H), 2.97 (dt, J=17.7, 6.3 Hz, 1 H), 3.12 (dd, J=17.7, 6.8 Hz, 1 H), 5.21 (sept, J=6.3 Hz, 1 H), 6.35 (t, J=6.3 Hz, 1 H), 7.25 (s, 1 H), 7.45 (d, J=8.1 Hz, 1 H), 7.59 (s, 1 H), 7.62 (dd, J=8.1, 1.5 Hz, 1 H), 7.78 (d, J=1.5 Hz, 1 H).

Provenance & Evidence