Triethylamine → (R)-7-Methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamine hydrochloride

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Reaction Conditions

Reaction Steps

A solution of 2 ml (0.0140 mol) of triethylamine in 20 ml of acetone and then 1.6 ml (0.0161 mol) of ethyl chloroformate in 20 ml of acetone are added slowly at a temperature of -10° C. to -5° C. to a solution of 2.5 g (0.0120 mol) of 7-methoxy-1,2,3,4-tetrahydro-(2R)-2-naphthoic acid in 30 ml of acetone. The mixture is stirred at -5° C. for 2 hours and a solution of 1.3 g (0.0193 mol) of NaN3 in 10 ml of water is then added dropwise. After 1 hour at -5° C., the mixture is poured into 200 ml of water and extracted with toluene. The two phases are separated, the organic phase is dried over sodium sulfate and filtered and the solution is heated at 100° C. for 1.5 hours. The solvent is evaporated off under reduced pressure, the residue is taken up with 22 ml of water and 26 ml of 37% hydrochloric acid and the mixture is refluxed for 3.5 hours. After cooling, the pH of the solution is rendered basic by the addition of 3.5N NaOH, extraction is carried out with ethyl ether, the organic phase is dried over sodium sulfate and the solvent is evaporated off under reduced pressure. The hydrochloride of the base obtained in this way is prepared with a saturated solution of hydrochloric acid in ethyl ether. This gives 1.6 g of the title compound, which is crystallized from isopropanol to give 1.2 g of product. M.p. 205° C.--207° C.; [α]D20 =+66.6° (c=0.5%, MeOH).

Provenance & Evidence