The present invention is directed to methods for the asymmetric synthesis of esketamine. The present invention is further directed to key intermediates in the asymmetric esketamine synthesis. In one embodiment, the invention is an asymmetric synthesis of esketamine comprising the conversion of (S)-2′-chloro-2-methoxy-3,4,5,6-5 tetrahydro-[1,1′-biphenyl]-3-yl carbamate to (S)-2′-chloro-1-isocyanato-6-methoxy-1,2,3,4-tetrahydro-1,1′-biphenyl.

##STR00001##

The present invention is directed to methods for the asymmetric synthesis of esketamine. The present invention is further directed to key intermediates in the asymmetric esketamine synthesis. In one embodiment, the invention is an asymmetric synthesis of esketamine comprising the conversion of (S)-2′-chloro-2-methoxy-3,4,5,6-5 tetrahydro-[1,1′-biphenyl]-3-yl carbamate to (S)-2′-chloro-1-isocyanato-6-methoxy-1,2,3,4-tetrahydro-1,1′-biphenyl.

##STR00001##

The invention concerns a new, efficient process for the preparation of enantiomerically pure norepinephrine (also known as noradrenaline), or an addition salt thereof, using a catalytic hydrogenation system under hydrogen donor transfer. The invention also discloses a novel intermediate and the process for the preparation thereof.

The invention concerns a new, efficient process for the preparation of enantiomerically pure norepinephrine (also known as noradrenaline), or an addition salt thereof, using a catalytic hydrogenation system under hydrogen donor transfer. The invention also discloses a novel intermediate and the process for the preparation thereof.

The invention concerns a new, efficient process for the preparation of enantiomerically pure norepinephrine (also known as noradrenaline), or an addition salt thereof, using a catalytic hydrogenation system under hydrogen donor transfer. The invention also discloses a novel intermediate and the process for the preparation thereof.

Provided is a method for preparing an N-cyclopropylmethyl aniline compound, which comprises hydrogenating a compound represented by Formula II and cyclopropyl formaldehyde as raw materials in the presence of an acid and catalyst to generate an N-cyclopropylmethyl aniline compound represented by Formula I, wherein R is alkoxy, alkylamino or a substituted anilino group represented by Formula III.

Provided is a method for preparing an N-cyclopropylmethyl aniline compound, which comprises hydrogenating a compound represented by Formula II and cyclopropyl formaldehyde as raw materials in the presence of an acid and catalyst to generate an N-cyclopropylmethyl aniline compound represented by Formula I, wherein R is alkoxy, alkylamino or a substituted anilino group represented by Formula III.

The invention concerns a new, efficient process for the preparation of enantiomerically pure norepinephrine (also known as noradrenaline), or an addition salt thereof, using a catalytic hydrogenation system under hydrogen donor transfer. The invention also discloses a novel intermediate and the process for the preparation thereof.

The invention concerns a new, efficient process for the preparation of enantiomerically pure norepinephrine (also known as noradrenaline), or an addition salt thereof, using a catalytic hydrogenation system under hydrogen donor transfer. The invention also discloses a novel intermediate and the process for the preparation thereof.

The invention concerns a new, efficient process for the preparation of enantiomerically pure norepinephrine (also known as noradrenaline), or an addition salt thereof, using a catalytic hydrogenation system under hydrogen donor transfer. The invention also discloses a novel intermediate and the process for the preparation thereof.