A compound which is: 4-amino-6-(1-(oxetan-3-yl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(3-(trifluoromethoxy)phenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-cyclobutyl-1 H -pyrrolo[2,3-b]pyridin-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-hydroxy-2-methylpropyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-(trifluoromethoxy)phenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-methoxy-4-(trifluoromethyl)phenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(3-(difluoromethoxy)phenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(3-isobutoxyphenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2- isopropoxyphenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(3,5-dichlorophenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(3,5-dichlorophenyl)-1 H -pyrrolo[2,3-b]pyridin-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2,3-dichlorophenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-methylpyrimidin-5-yl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(6-methylpyridin-3-yl)-1 H -pyrrolo[2,3-b]pyridin-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(1-methyl-6-oxo-1,6-dihydropyridin-3-yl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-hydroxyphenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-(cyclopentyloxy)phenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-hydroxyphenyl)-1 H -pyrrolo[2,3-b]pyridin-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-(cyclopentyloxy)phenyl)-1 H -pyrrolo[2,3-b]pyridin-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-ethoxyphenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(5-methyl-1,3,4-oxadiazol-2-yl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(7-cyclopropyl-1-propyl-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; N -(5-(4-amino-5-oxo-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-6(5 H)-yl)-1-(2-methoxyphenyl)-1 H -indol-7-yl)cyclopropanecarboxamide; 4-amino-6-(1-isopropyl-7-morpholino-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; or N -(5-(4-amino-5-oxo-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-6(5 H)-yl)-1-isopropyl-1 H- indol-7-yl)cyclopropanecarboxamide; or a pharmaceutically acceptable salt thereof. 4-amino-6-(1-(oxetan-3-yl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(3-(trifluoromethoxy)phenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-cyclobutyl-1 H -pyrrolo[2,3-b]pyridin-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-hydroxy-2-methylpropyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-(trifluoromethoxy)phenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-methoxy-4-(trifluoromethyl)phenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(3-(difluoromethoxy)phenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(3-isobutoxyphenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2- isopropoxyphenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(3,5-dichlorophenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(3,5-dichlorophenyl)-1 H -pyrrolo[2,3-b]pyridin-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2,3-dichlorophenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-methylpyrimidin-5-yl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(6-methylpyridin-3-yl)-1 H -pyrrolo[2,3-b]pyridin-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(1-methyl-6-oxo-1,6-dihydropyridin-3-yl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-hydroxyphenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-(cyclopentyloxy)phenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-hydroxyphenyl)-1 H -pyrrolo[2,3-b]pyridin-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-(cyclopentyloxy)phenyl)-1 H -pyrrolo[2,3-b]pyridin-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(2-ethoxyphenyl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(1-(5-methyl-1,3,4-oxadiazol-2-yl)-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; 4-amino-6-(7-cyclopropyl-1-propyl-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; N -(5-(4-amino-5-oxo-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-6(5 H)-yl)-1-(2-methoxyphenyl)-1 H -indol-7-yl)cyclopropanecarboxamide; 4-amino-6-(1-isopropyl-7-morpholino-1 H -indol-5-yl)-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-5(6 H)-one; or N -(5-(4-amino-5-oxo-7,8-dihydropyrimido[5,4- f][1,4]oxazepin-6(5 H)-yl)-1-isopropyl-1 H- indol-7-yl)cyclopropanecarboxamide;