Patent US5466799 (http://l2.espacenet.com/dips/viewer?PN=US5466799&CY=gb&LG=en&DB=EPD)
Abstract
A general method is provided for the synthesis of substituted 2,3-dihydro-5-phenyl-1H-1,4-benzodiazepines by the reaction of bis-trifiated-2,5-dihydroxy benzophenones with 1,2-bisaminoethanes, followed by displacement of the 7-trifloxy group.
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...Although 5-phenyl-3H-1,4-benzodiazepin-2-(1H)-one can be prepared from 2-aminobenzophenone and glycine ether ester hydrochloride in one step, the synthesis of ring-substituted benzodiazepines requires the use of bis-substituted benzophenones, such as 2-amino-5-chlorobenzophenone, that are both more difficult to obtain and to manipulate. See, for example, U.S. Pat. No. 3,313,815. Thus, a need exists for new syntheses of benzodiazepines that can be readily adapted to the synthesis of a variety of known and novel diazepam analogs...
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Spisshak: It might be found in https://www.thevespiary.org/rhodium/Rhodium/pdf/benzodiazepine.chemistry.review.pdf (https://www.thevespiary.org/rhodium/Rhodium/pdf/benzodiazepine.chemistry.review.pdf)