The present invention relates to a process for synthesizing large scale a compound of formula (I), or pharmacuetically acceptable salt thereof, which is useful as the key intermediate for the synthesis of compounds for prophylaxis and treatment of a disease associated with the deposition of β-amyloid in the brain, in particular Alzheimer's disease, and other diseases such as cerebral amyloid angiopathy, hereditary cerebral hemorrhage with amyloidosis, Dutch-type (HCHWA-D), multi-infarct dementia, dementia pugilistica and Down syndrome.

##STR00001##

The present invention relates to a process for synthesizing large scale a compound of formula (I), or pharmacuetically acceptable salt thereof, which is useful as the key intermediate for the synthesis of compounds for prophylaxis and treatment of a disease associated with the deposition of β-amyloid in the brain, in particular Alzheimer's disease, and other diseases such as cerebral amyloid angiopathy, hereditary cerebral hemorrhage with amyloidosis, Dutch-type (HCHWA-D), multi-infarct dementia, dementia pugilistica and Down syndrome.

##STR00001##

There is herein provided a compound of formula (I). ##STR00001##

There is herein provided a compound of formula (I). ##STR00001##

There is herein provided a compound of formula (I) or a pharmaceutically acceptable salt thereof, wherein X, R.sup.1, R.sup.2, R.sup.3, R.sup.4 and n have meanings as provided in the description. ##STR00001##

There is herein provided a compound of formula (I) or a pharmaceutically acceptable salt thereof, wherein X, R.sup.1, R.sup.2, R.sup.3, R.sup.4 and n have meanings as provided in the description. ##STR00001##

There is herein provided a compound of formula (I).

##STR00001##

There is herein provided a compound of formula (I).

##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.