Process for synthesising aminoadamantanes

Process for synthesizing aminoadamantanes of formula I

• in which R1 and R2 are identical or different and are H or a straight or branched alkyl group comprising from 1 to 6 carbon atoms, from acetamido adamantane of formula II
• in which R1 and R2 are as aforestated, comprising the following stages:
• stage 1) synthesizing acetamido adamantanes of formula II from a halogen adamantine of formula III
• in which R1 and R2 are as above, and in which X is F, Cl, Br or I, through the following steps:
• (a1) feeding into a reaction vessel a mixture comprising the halogen adamantane of formula III, 5-10 equivalents of acetonitrile and 5-20 equivalents of glacial acetic acid, to provide a reaction mixture,
• (b1) introducing into the reaction mixture 3-10 equivalents of concentrated sulfuric acid, to provide a reacted mixture, or alternatively:
• (a2) feeding into the reaction vessel a mixture comprising the halogen adamantine of formula III, 5-20 equivalents of glacial acetic acid and 3-10 equivalents of concentrated sulfuric acid, to provide a reaction mixture,
• (b2) introducing into the reaction mixture 5-10 equivalents of acetonitrile to provide a reacted mixture, and
• (c) isolating the acetamido adamantine of formula II formed in step (b1) or (b2) from the reacted mixture;
• wherein a reaction temperature of 50° C.-90° C. is maintained during introduction of sulfuric acid or of acetonitrile in step (b1) or (b2);
• and
• stage 2) synthesizing aminoadamantanes of formula I from acetamido adamantane of formula II of stage 1) through the following steps:
• (a) feeding into a reaction vessel a mixture comprising acetamido adamantane of formula II, 5-20 equivalents of an alkali metal or alkaline earth metal hydroxide and a solvent chosen from the group consisting of 1-methoxy-2-propanol, 2-methoxy-1-propanol, 3-methoxy-1-propanol, 2-ethoxyethanol, 2-methoxyethanol and mixtures thereof, to provide a hydrolysis mixture,
• (b) heating the hydrolysis mixture under reflux for a time sufficient to achieve hydrolysis of the acetamido adamantane of formula II to give the corresponding aminoadamantane of formula I, and
• (c) isolating the aminoadamantane of formula I formed in step (b), preferably by conversion into an addition salt thereof.