Syntheses and crystal structures of the anhydride 4-oxa-tetra-cyclo-[5.3.2.02,6.08,10]dodec-11-ene-3,5-dione and the related imide 4-(4-bromo-phen-yl)-4-aza-tetra-cyclo-[5.3.2.02,6.08,10]dodec-11-ene-3,5-dione.

Andrew Hulsman,William R Winchester,Isabel Lorenzana,Brock A Stenfors,Breezy Squires,Mason Tolonen,Shannon M Biros,Richard J Staples,Theodore Schultz

doi:10.1107/s2056989020009512

Abstract

The syntheses and crystal structures of the two title compounds, C11H10O3 (I) and C17H14BrNO2 (II), both containing the bi-cyclo-[2.2.2]octene ring system, are reported here [the structure of I has been reported previously: White & Goh (2014 ▸). Private Communication (refcode HOKRIK). CCDC, Cambridge, England]. The bond lengths and angles of the bi-cyclo-[2.2.2]octene ring system are similar for both structures. The imide functional group of II features carbonyl C=O bond lengths of 1.209 (2) and 1.210 (2) Å, with C-N bond lengths of 1.393 (2) and 1.397 (2) Å. The five-membered imide ring is nearly planar, and it is positioned exo relative to the alkene bridgehead carbon atoms of the bi-cyclo-[2.2.2]octene ring system. Non-covalent inter-actions present in the crystal structure of II include a number of C-H⋯O inter-actions. The extended structure of II also features C-H⋯O hydrogen bonds as well as C-H⋯π and lone pair-π inter-actions, which combine together to create supra-molecular sheets.

Highlights

Andrew Hulsman,a Isabel Lorenzana,a Theodore Schultz,a Breezy Squires,a Brock A
The bond lengths and angles of the bicyclo[2.2.2]octene ring system are similar for both structures
Non-covalent interactions present in the crystal structure of II include a number of C—HÁ Á ÁO interactions

Summary

Chemical context

Cycloheptatriene, a, exhibits valence isomerism with norcaradiene, b, in solution (Fig. 1). The norcaradiene isomer readily reacts with maleic anhydride, c, to form the unique tricyclic anhydride, I (White & Goh, 2014) This reaction has been known since 1939 (Kohler et al, 1939), but the structure of the major product was not determined until 1953, when it was elucidated that the product contained a cyclopropane ring (Alder & Jacobs, 1953). Tecoviramat has been approved as a treatment for smallpox, and the United States has created a stockpile of two million doses stored at the US Strategic National Stockpile (Hughes, 2019) Substituted anilines, such as p-bromoaniline f, have been reacted with the anhydride I to form imides that show insecticidal activity (Fig. 2, Brechbuhler & Petitpierre, 1975). The structure of the anhydride was previously reported as a Private Communication to the CSD (refcode HOKRIK; White & Goh, 2014)

Structural commentary

Supramolecular features

Synthesis and crystallization

Database survey