Synthesis and crystal structure of 3,5,9,11-tetraacetyl-14-oxo-1,3,5,7,9,11-hexaazapentacyclo[5.5.3.02,6.04,10.08,12]pentadecane

Crystals of 3,5,9,11-tetraacetyl-14-oxo-1,3,5,7,9,11-hexaazapentacyclo[5.5.3.02,6.04,10 .08,12]pentadecane, a new hexaazaisowurtzitane derivative, were obtained from a condensation reaction of 2,6,8,12-tetraacetyl-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.05,9.03,11] dodecane with aqueous formaldehyde and subsequent crystallization of the product from aqueous acetone. X-ray diffraction analysis at room temperature indicates that the compound crystallizes in monoclinic system, space group P21/n with a= 9.4564(15), b= 14.184(2), c= 13.334(2) A, β = 107.671(4)◦, V= 1704.1(5) A3, Z= 4, Dcalc = 1.475 g/cm3, F(000)= 800, μ(MoKα)= 0.112 mm−1, and final R1 = 0.0505, wR2 = 0.1215 for observed reflections 2641 (I> 2σ (I)). The ether link (C–O–C) forms two heptacyclic rings with the N, C atoms in the cage respectively. The results of elemental analysis, IR and NMR spectroscopy are included.