title: 5-tert-Butyl 1-ethyl 3-amino-1,4,5,6-tetra-hydro-pyrrolo-[3,4-c]pyrazole-1,5-dicarboxyl-ate.
abstract: The asymmetric unit of the title compound, C(13)H(20)N(4)O(4), contains two crystallographically independent mol-ecules in which the dihedral angles between the fused pyrrole and pyrazole rings are 5.06 (8) and 1.12 (8)°. In the crystal, mol-ecules are linked by inter-molecular N-H⋯O and N-H⋯N hydrogen bonds into chains parallel to the b axis.
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Xia
authors.forename: Xiao-Guang
authors.initials: XG
authors.lastname: Bai
authors.forename: Hong-Tao
authors.initials: HT
authors.lastname: Liu
authors.forename: Ju-Xian
authors.initials: JX
authors.lastname: Wang