Crystal structure of methyl 1-methyl-2-oxo­spiro­[indoline-3,2′-oxirane]-3′-carboxyl­ate

In the title compound, C(12)H(11)NO(4), the dihedral angle between the indole ring system (r.m.s. deviation = 0.019 Å) and the oxirane ring is 88.8 (2)°. The oxirane O atom and the bridging ester O atom are in an approximate syn conformation [O—C—C—O = −25.4 (3)°] In the crystal, inversion dimers linked by pair of C—H⋯O hydrogen bonds generate R (2) (2)(8) loops, where the C—H donor group forms part of the oxirane ring. A second C—H⋯O inter­action arising from one of the C—H groups of the benzene ring links the dimers into [001] double chains.