Pyrimidine complexes with

Nevertheless, these restrictions obtain for most purine and pyrimidine complexes with (NH3) Ru(III), so that this and related equations have considerable predictive power (as will be seen below.)... 

This way the presented variational QSAR anti-HIV mechanism assures the stabilization of pyrimidine complex with the enzyme transcriptase receptor towards the concerned apoptosis of the HIV cells through inhibiting his enzymic activities for further actions (and replications) in organism. 

Diorganotin(IV) complexes with 4//-pyrido[l,2-n]pyrimidin-4-ones 109 (96MI4), complexes of 2-methyl- and 2-methyl-8-nitro-9-hydroxy-4//-pyrido[l,2-n]pyrimidin-4-ones with Ag(I), Cu(II), Ni(II), Co(II), and Mn(II) ions (00MI23), 2,4-dimethyl-9-hydroxypyrido[l, 2-n]pyrimidinium perchlorate and its complexes with prasedynium, neodymium, samarium and europium (00MI24) were characterized by UV spectroscopy. 

Charge-transfer complexes with pyrimidine and purine bases as well as with solvents like hexa-methylphosphoramide and dimethyl sulfoxide are reported in Ref 66. The action of aromatic amines (primary, secondary, or tertiary) resulted in fume-offs or unidentifiable tars, in all cases purple or red colors developed prior to more violent reactions (Ref 66)... 

Fig. 3.1 Schematic representation of the two modes of distamycin DNA complexes with putative hydrogen bonds shown as dashed lines. Circles with dots represent lone pairs of N(3) of purines and 0(2) of pyrimidines...

It is noteworthy that, as early as 1929, Shibata and Tsuchida reported a kinetic resolution of rac-3,4-dihydroxyphenylalanine by selective oxidation of one enantiomer using a chiral cobalt complex [Co(en)3NH3Cl]Br2 as a catalyst [46,47]. Figure 12 shows a highly enantioselective addition of diisopropy-Izinc to 2-(ferf-butylethynyl)pyrimidine-5-carbaldehyde via an autocatalytic process in the presence of a chiral octahedral cobalt complex with ethylenedi-... 

Regular pyrimidines are less effective ligands for Ni11 ions. They may use, inter alia, their C=0 donor to yield monodentate coordination.1835 Insertion of a sulfur atom into a pyrimidine moiety increases considerably its binding ability.1836 Thiolation of uridine at C(2) or C(4) results in formation of a quite effective S,N3 four-membered chelate in the complexes with Ni11. Thiolation of purine at C(6) increases the stability constant by 3.5 orders of magnitude. 

A measure of the promiscuity of these diacids was attempted with pyrimidine 26 vs pyrazine 20. The two heterocycles differ in size, shape and also basicity in addition, stacking interactions can be observed in the pyrimidine complex but not with pyrazine. These four variables make interpretation with confidence somewhat futile since it is difficult to attribute the binding differences to any particular feature. 

Fig. 6. Difference spectra between xanthine oxidase inactivated with various pyra-zolo [3, 4-d] pyrimidines and the native enzyme. The spectra are believed to represent the increase in absorption occurring when Mo(VI) of native enzyme is converted to Mo(IV) complexed with the inhibitors. Spectra were obtained by treating the enzyme with inhibitors in the presence of xanthine, then admitting air, so as to re-oxidize the iron and flavin chromophores. The extinction coefficients, de, are expressed per mole of enzyme flavin. Since some inactivated enzyme was present, extinction coefficients per atom of molybdenum of active enzyme will be about 30% higher than these values. (Reproduced from Ref. 33, with the permission of Dr. V. Massey.)...

Photoreactions of Metal Complexes with DNA closer to the purine strand than to the pyrimidine strand in the major groove. 

Reaction of hydroxyalkylbiuret derivatives 16 and diethyl carbonate yields 1-(hydroxyalkyl)-133-triazin-2,4,6-triones 17, which lead to the corresponding 1-(carboxyalkyl)-13,5-triazin-2,4,6-triones 18. Triazinones 18 afford 1 1 complexes with a series of aminoalkyl substituted pyrimidine-2,4,6-triamines, which form hydrogen-bonded molecular ribbons <99CEJ381>. 

Basosi, R., Gaggelli, E., Tiezzi, E., and Valensin, G. (1975). Nitrosyliron complexes with mercaptO purines and -pyrimidines studied by nuclear magnetic and electron spin resonance spectroscopy. J. Chem. Soc. Perkin Trans. 2, 423-428. 

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