Synthesis of Unsymmetrically Substituted 4,6,10-Trihydroxy-1,4,6,10-tetra­azaadamantanes via Intramolecular Cyclization of Tris(β-oximinoalkyl)amines

Abstract

The cyclotrimerization of oximino groups in unsymmetrically substituted tris(β-oximinoalkyl)amines was studied. A general approach to the synthesis of 4,6,10-trihydroxy-1,4,6,10-tetraazaadamantanes containing different substituents at bridgehead carbon atoms was developed from available aliphatic nitro compounds.

Key words

cyclization - heterocycles - amines - oximes - adamantanes

References

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8

An additional role of acetic acid may involve quaternization of the bridgehead nitrogen atom in tetraazaadamantanes 2, which shifts the equilibrium between 1 and 2 towards 2.^²

9

X-ray data for 2(4e)˙7H₂O: Empirical formula: C₃₆H₆₈Br₂N₈O₁₇; M = 1044.80; triclinic; space group P1; T = 103 K; a = 8.4154(6), b = 10.0049(7), c = 14.4240(11) Å, α = 87.414(2), β = 86.468(2), γ = 83.935(3)˚; V = 1204.43(15) Å^³; Z = 1; d_calc = 1.440 gcm^-³; µ(Mo_{K α}) = 17.57 cm^-¹; F(000) = 546. Intensities of 13428 reflections were measured with a Bruker SMART APEX2 CCD diffractometer [λ(Mo_{K α}) = 0.71072Å, ω-scans, 2θ<58˚], and 6386 independent reflections [R _int = 0.0342] were used in further refinement. The structure was solved by direct methods and refined by the full-matrix least-squares technique against F^² in the anisotropic-isotropic approximation. The hydrogen atoms of OH groups and those of water molecules were found in difference Fourier synthesis. The H(C) atom positions were calculated. All hydrogen atoms were refined in the isotropic approximation within the riding model. For 2(4e)˙7H₂O, the refinement converged to wR2 = 0.0840 and GOF = 1.002 for all the independent reflections (R1 = 0.0494 was calculated against F for 3820 observed reflections with I>2σ(I)). All calculations were performed using SHELXTL PLUS 5.0.^¹0 CCDC-843973 contains the supplementary crystallographic data for 2(4e)˙7 H₂O. These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html (or from the CCDC, 12 Union Road, Cambridge, CB21EZ, UK; or [e-mail]).