rac-(4R,17S,18R,26R)-Ethyl 4′-methoxycarbonyl-5′′-(4-methoxyphenyl)-1′-methyl-2,3′′-dioxo-2′′,3′′-dihydroindoline-3-spiro-2′-pyrrolidine-3′-spiro-2′′-thiazolo[3,2-a]pyrimidine-6′′-carboxylate

In the title compound, C30H30N4O7S, the two spiro junctions link a planar 2-oxindole ring [with a mean deviation from the plane of 0.0319 (3) Å, a pyrrolidine ring in an envelope conformation and a thiazolo[3,2-a]pyrimidine system. Two molecules are connected into a dimer by two N—H⋯O hydrogen bonds, forming an R 2 2(8) graph-set motif. The title compound has four stereogenic centers and appears as a racemic mixture of one single diastereoisomer (RSRR/SRSS).

In the title compound, C 30 H 30 N 4 O 7 S, the two spiro junctions link a planar 2-oxindole ring [with a mean deviation from the plane of 0.0319 (3) Å , a pyrrolidine ring in an envelope conformation and a thiazolo[3,2-a]pyrimidine system. Two molecules are connected into a dimer by two N-HÁ Á ÁO hydrogen bonds, forming an R 2 2 (8) graph-set motif. The title compound has four stereogenic centers and appears as a racemic mixture of one single diastereoisomer (RSRR/SRSS).
The title compound has 4 stereogenic centers and then appears as a racemic mixture of one single diastereoisomer (RSRR/ SRSS).
supplementary materials sup-2 Refinement All H atoms attached to C atoms and N atom were fixed geometrically and treated as riding with C-H = 0.96Å (methyl), 0.97Å (methylene), 0.98Å (methine) and N-H = 0.86 Å with U iso (H) = 1.2U eq (C or N) or U iso (H) = 1.5U eq (methine). Fig. 1. The molecular structure of (I) with the atom-labeling scheme. Ellipsoids are drawn at the 30% probability level. H atoms have been omitted for clarity.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.