The first example of the stereoselective synthesis and crystal structure of a spirobicycloquinazolinone based on (–)-fenchone and anthranilamide

The possibility of a single-stage solvent-free stereoselective synthesis of a spirocyclic compound from the natural bicyclic monoterpenoid (−)-fenchone and anthranilamide has been shown for the first time. The molecular and crystal structure of (1R,2S,4S)-1,3,3-trimethyl-1′H-spiro[bicyclo[2.2.1]heptane-2,2′-quinazolin]-4′(3′H)-one, C₁₇H₂₂N₂O, was established by X-ray diffraction though the chirality was assumed via the known reactant connectivity and ¹H and ¹³C NMR spectroscopy. It has shown that in the molecule, for steric reasons, there is an elongation of the Me₂C—C(N)N bond to 1.603 (5) Å. The formation of dimers via N—H...O=C hydrogen bonds with an interaction energy of 93.30 kJ mol⁻¹ and through cavities (33.7% of the unit-cell volume) was established in the packing of the molecules. There are no π-stacking interactions in the structure.