4-[(4-Ethoxy­phen­yl)amino­acet­yl]-6,7-dimethyl-1,2,3,4-tetra­hydro­quinoxalin-2-one

All the inter­atomic distances in the title compound, C22H25N3O4, are normal. The heteroatom ring of the quinoxalinone system shows a half-chair conformation, slightly distorted towards a sofa. In the crystal structure, the mol­ecules dimerize via a pair of N—H⋯O hydrogen bonds. The dimers are linked by C—H⋯O and possible C—H—π inter­actions into a three-dimensional network.