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1,3,5-Triamino-1,3,5-trideoxy- cis -inositol and all-cis -2,4,6-Trimethoxycyclohexane- 1,3,5-triamine as Building Blocks for New Multidentate and Macrocyclic Ligands 1

1998; American Chemical Society; Volume: 37; Issue: 24 Linguagem: Inglês

10.1021/ic980483w

1520-510X

Κ. Hegetschweiler, Michael Weber, Volker Hüch, Rodney J. Geue, A. D. Rae, Anthony C. Willis, Alan M. Sargeson,

Synthesis and Characterization of Heterocyclic Compounds

Treatment of the two CoIII-hexaamine complexes [Co(taci)2]3+ and [Co(tmca)2]3+ (taci = 1,3,5-triamino-1,3,5-trideoxy-cis-inositol, tmca = all-cis-2,4,6-trimethoxycyclohexane-1,3,5-triamine) in CH3CN with NEt3 and excess paraformaldehyde gave the corresponding hexamethylideneimino (hmi) derivatives [Co(taci)2-hmi]3+ and [Co(tmca)2-hmi]3+ in excellent yield. Both hexaimines were stable in acidic aqueous solution and were isolated as solid compounds. They were characterized by elemental analyses, 13C NMR, 1H NMR, IR, and visible spectroscopy, mass spectrometry, and single-crystal X-ray analyses. [Co(taci)2-hmi]Cl3·6H2O crystallizes in the monoclinic space group C2/m, C18Cl3CoH42N6O12, Z = 2, a = 13.046(2) Å, b = 9.802(2) Å, c = 12.332(2) Å, β = 118.42(1)°. [Co(tmca)2-hmi](HSO4)3 crystallizes in the monoclinic space group C2/c, C24CoH45N6O18 S3, Z = 4, a = 14.087(3) Å, b =15.890(3) Å, c = 15.502(3) Å, β = 95.27(3)°. Subsequent treatment of [Co(taci)2-hmi]3+ with nitromethane and base resulted in the formation of [Co(hebdoc)]+ (hebdoc = 8,10,18,20,21,22-hexahydroxy-9,19-bis(methylamino)-4,14-dinitro-2,6,12,16-tetraazatricyclo[15.3.1.17,11]docosa-2,12-diene-4,14-diate), where the two taci fragments were fused by two anionic NCH−C(NO2-)−CH2−NH bridges. Two major diastereoisomers were formed from fifteen possibilities. They had different configurations at coordinated methylamino groups and were incorporated in a disordered manner in the crystal structure of [Co(hebdoc)]2Cl2·3.5H2O: C40Cl2Co2H75N16O23.50, orthorhombic, space group Pna21, Z = 4, a = 33.835(2) Å, b = 15.356(2) Å, c = 9.967(2) Å. In the base-catalyzed reaction of [Co(tmca)2]3+ with an appropriate mixture of formaldehyde and acetaldehyde, the condensation process was followed by a coupling reaction. After reduction with NaBH4 and air oxidation, a CoIII complex with the novel hexadentate ligand N-(9'-amino-8',10',11'-trimethoxy-2',6'-diaza-bicyclo[5.3.1]undec-4'-yl-methyl)-2,4,6-trimethoxycyclohexane-1,3,5-triamine was formed as the major product. Direct treatment of [Co(taci)2-hmi]3+ and [Co(tmca)2-hmi]3+ with NaBH4 resulted in the liberation of the new triamines 1,3,5-trideoxy-1,3,5-tris(methylamino)-cis-inositol and all-cis-2,4,6-trimethoxytris(N-methyl)cyclohexane-1,3,5-triamine.