2-Amino-5-chlorobenzophenone is a substituted benzophenone that can be used in the synthesis of benzodiazepines.
Chemistry
2-Amino-5-chlorobenzophenone is a substituted derivative of benzophenone, where the hydrogen atom at the 2 position has been replaced by an amino group (-NH2) and the one at the 5 position replaced with a chlorine atom.[1]
Synthesis
Among other methods, 2-amino-5-chlorobenzophenone can be synthesized by reducing isoxazole through iron powder. This process also involves using toluene and muriatic acid.[3]
Synthesis of benzodiazepines
2-Amino-5-chlorobenzophenone and its derivatives can be used to produce benzodiazepines, a few examples are listed below;
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.[5]
^CN104230727A, 刘为焱; 潘明 & 黄雄, "Synthesis technology for producing 2-amino-5-chlorobenzophenone by reducing isoxazole through iron powder", issued 2014-12-24
^Humans, IARC Working Group on the Evaluation of Carcinogenic Risks to (1996), "Prazepam", Some Pharmaceutical Drugs, vol. 66, International Agency for Research on Cancer, pp. 143–155, PMC7681523, PMID9097122, retrieved 2024-02-16