Abstract: In order to explore the reactivity of tetraacetylhexaazaisowurtzitane （TAIW）, an important nitrolyzable precursor for the synthesis of CL-20, it was condensed with aqueous formaldehyde to give a new hexaazaisowurtzitane derivative, 2,6,8,12-tetraactyl-14-oxo-2,4,6,8,10,12-hexaazapentacyclo （） pentadecane. The new compound was struc-turally characterized by elemental analysis, IR, （）<sup<1</sup<H NMR, （）<sup<13</sup<C NMR and MS.