1,3-Diazepine deriv. AIDS-043313 AIDS043313 XV651 [4R-(4.alpha.,5.alpha.,6.beta.,7.beta.)]-3-[[3-(Cyclopropylmethyl)hexahydro-5,6-dihydroxy-2-oxo-4,7-bis(phenylmethyl)-1H-1,3-diazepin-1-yl]methyl]-N-1H-imidazol-2-ylbenzamide