[2,13-Bis(acetamido)-5,16-dimethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosane]copper(II) dichloride octahydrate

Semisynthesis of an Anticancer DPAGT1 Inhibitor from a Muraymycin Biosynthetic Intermediate

We have explored a method to convert a muraymycin biosynthetic intermediate 3 to an anticancer drug lead 2 for in vivo and thorough preclinical studies. Cu(OAc)2 forms a stable complex with the amide 4 and prevents electrophilic reactions at the 2-((3-aminopropyl)amino)acetamide moiety. Under the present conditions, the desired 5″-primary amine was selectively protected with (Boc)2O to yield 6. The intermediate 6 was converted to 2 in two steps with 90% yield.

Crystal structure of [2,13-bis-(acetamido)-5,16-dimethyl-2,6,13,17-tetra-aza-tri-cyclo-[16.4.0.07,12]docosane-κ4N]silver(II) dinitrate from synchrotron X-ray data

The asymmetric unit of the title compound, [Ag(C24H46N6O2)](NO3)2 [C24H46N6O2 is (5,16-dimethyl-2,6,13,17-tetra-aza-tri-cyclo-[16.4.0.07,12]docosane-2,13-di-yl)diacetamide, L], consists of one independent half of the [Ag(C24H46N6O2)]2+ cation and one nitrate anion. The Ag atom, lying on an inversion centre, has a square-planar geometry and the complex adopts a stable trans-III conformation. Inter-estingly, the two O atoms of the pendant acetamide groups are not coordinated to the AgII ion. The longer distance of 2.227 (2) Å for Ag-N(tertiary) compared to 2.134 (2) Å for Ag-N(secondary) may be due to the effects of the attached acetamide group on the tertiary N atom. Two nitrate anions are very weakly bound to the AgII ion in the axial sites and are further connected to the ligand of the cation by N-H⋯O hydrogen bonds. The crystal packing is stabilized by hydrogen-bonding inter-actions among the N-H donor groups of the macrocycle and its actetamide substituents, and the O atoms of the nitrate anions and of an acetamide group as the acceptor atoms.