Crystal and molecular structure of (9aS,10S)-6-Oxo-6,7,8,9,9a,10-hexahydro-4H-thieno-[2,3-b]quinolizin-10-yl acetate

The title compound, C₁₃H₁₅NO₃S, is a chiral molecule with two stereogenic centres. Its absolute configuration was derrived from the synthesis and confirmed by structure determination. The expected stereochemistry of atoms C5 and C6 was confirmed to be S. The central N-heterocyclic rings are not planar and adopt a half-chair conformation. A calculation of least-squares planes showed that these rings are puckered in such a manner that the five atoms C1, C2, C3, C5 and N1 (second ring: N1, C6, C7, C10 and C11) are planar, while atoms C4 (C5) are displaced from these planes with the out-of-plane displacement of 0.582 (3) Å and 0,666 (2) Å in the second ring, respectively. Dihedral angle between the planes of the central N-heterocyclic rings is 40.0 (1)°. Crystal structure is stabilized by C—H···O hydrogen interactions.