Synthesis Of Optically Pure 1,2,3,4-tetrahydro-naphthalene-1-amine And Its Derivatives

Chiral amines are widespread in nature, they are important structural elements of many bioactive molecules, natural products and important chiral intermediates of synthetic drugs, chiral amines are also useful resolution reagents. Optically pure 1,2,3,4-tetrahydronaphthalen-l-amine is an important pharmaceutical intermediate.In this paper, we started from a-tetralone, which was treated with hydroxylamine to form oxime. With Pd/C as the catalyst, the oxime was reduced to amine by catalytic hydrogenation in the presence of L-or D-tartaric acid. (R)-1-Amino-tetrahydronaphthalene hydrogen L-tartrate or (S)-1-amino-tetrahydronaphthalene hydrogen D-tartrate was obtained respectively. The optically pure amines were given after treated with base in a total yield of 70%. The racemization of optically active 1,2,3,4-tetrahydronaphthalen-l-amine by catalytic hydrogenation was also studied.On the other hand, optically pure (R)- and (S)-1,2,3,4-tetrahydronaphthalen-1-amine were used as the starting material to prepare aminonaphthyl alcohol stereoselectively. Acylation of these optically pure amines with acetic anhydride, benzoyl chloride or phthalic anhydride followed by oxidation with potassium permanganate to give acylated aminonaphthyl ketones in yields of 65-85%. These aminonaphthyl ketones were reduced stereoselectively to afford the aminonaphthyl alcohols mainly in ci(S)-form, which was confirmed by 2D NMR. When phthalic anhydride was used as the protecting group, (R)- and (S)-aminonaphthyl alcohols were obtained in d.e.% of 92.6% and 98.2% respectively by reduction with DIBAL-H.