2-Amino-5-chlorobenzophenone

2-Amino-5-chlorobenzophenone is a substituted derivative of benzophenone, where the hydrogen atom at the 2 position has been replaced by an amino group (-NH2) and the one at the 5 position replaced with a chlorine atom. == Synthesis of benzodiazepines ==

2-Amino-5-chlorobenzophenone and its derivatives can be used to produce benzodiazepines, a few examples are listed below; Prazepam Prazepam can be produced by the acylation of 2-amino-5-chlorobenzophenone with cyclo-propanecarbonyl chloride and triethylamine, 2-cyclopropylmethylamino-5-chlorobenzhydrol is then obtained by using lithium aluminium hydride as a reducing agent, this product is then oxidized by using manganese dioxide. The resulting compound goes another acylation reaction using phthalimidoacetyl chloride and finally treated with hydrazine hydrate to produce prazepam. Lorazepam Lorazepam can be made using 2-amino-2′,5-dichlorobenzophenone (a derivative of 2-amino-5-chlorobenzophenone), which is first reacted with hydroxylamine, the obtained product is then reacted with chloroacetyl chloride to give 6-chloro-2-chlormethyl-4-(2′-chlorophenyl)quinazolin-3-oxide, a reaction with methylamine produces ring expansion and rearrangement, which forms 7-chloro-2-methylamino-5-(2′-chlorphenyl)-3H-1,4-benzodiazepin-4-oxide, acetylation with acetic anhydride gives a product which goes under hydrolysis by reacting it with hydrochloric acid, this gives 7-chloro-5-(2′-chlorophenyl)-1,2-dihydro-3H-1,4-benzodiazepin-2-on-4-oxide, a second reaction with acetic anhydride gives 7-chloro-1,3-dihydro-3-acetoxy-5-(2′-chlorphenyl)-2H-benzodiazepin-2-one, the last step involves hydrolysis of this product under sodium hydroxide to give lorazepam. Chlordiazepoxide To make chlordiazepoxide, 2-amino-5-chlorobenzophenone is first reacted with hydroxylamine, the resulting product is then reacted with chloracetyl chloride in acetic acid, resulting in 6-chloro-2-chloromethyl-4-phenylquinazolin-3-oxide, reaction with methylamine gives chlordiazepoxide. == References ==