Triphenylphosphine → 3-(7-bromo-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-bromo-1,2,3,4-tetrahydro-naphthalen-1-ol (2.5 g, 11.0 mmol) and isopropyl 4-imidazolecarboxylate (1.18 g, 7.66 mmol), which can be prepared as described in Example 1, (2.33 g, 10.98 mmol) in THF (20 mL) at 0° C. is added triphenylphosphine and dimethyl azodicarboxylate (40% wt. in toluene, 4.01 g, 10.98 mmol). After 10 min, the cooling bath is removed and after another 30 min, water is added and the mixture is extracted twice with ethyl acetate. The organic layers are dried over magnesium sulfate, filtered, and concentrated. The resulting residue is purified by silica gel chromatography (elution with hexanes-ethyl acetate mixtures) to give 3-(7-bromo-1,2,3,4-tetrahydro-naphthalen-1-yl)-3H-imidazole-4-carboxylic acid isopropyl ester; MS: (ESI) m/z 363.02, 365.02 (M+H)+; 1H NMR (400 MHz, MeOD) δ ppm 1.42 (d, J=6.1 Hz, 3 H), 1.44 (d, J=6.3 Hz, 3 H), 1.73-1.84 (m, 1 H), 1.89-1.98 (m, 1 H), 2.26-2.40 (m, 2 H), 2.82-2.91 (m, 1 H), 3.00 (dt, J=17.2, 5.6 Hz, 1 H), 5.27-5.37 (m, 1 H), 6.50 (t, J=5.3 Hz, 1 H), 7.26 (d, J=8.3 Hz, 1 H), 7.32 (d, J=2.1 Hz, 1 H), 7.51 (dd, J=8.3, 2.1 Hz, 1 H), 8.23 (d, J=1.5 Hz, 1 H), 8.50 (d, J=1.0 Hz, 1 H).

Provenance & Evidence