Structure analogues

Oxygen can be present in naphthenic acids, phenols and furan (analogue structures to thiophene and pyrrole) and higher derivatives. Oxygenated compounds give rise to corrosion and product deterioration. Hydrodeoxygenation is particularly important in the upgrading of biomass. 

Poly(dG-dC) poly(dG-dC) and its methylated analogue structures assume left-handed conformation (Z-DNA) in high molar sodium salt (Na", K" ), in low molar divalent cations (Ca", Mg", Ni ), micromolar concentrations of hexaamine cobalt chloride (Co(NH3)6)Cl3 and in millimolar concentrations of polyamines. In order to analyse the binding of berberine to Z-form DNA, Kumar et al. [186] reported that the Z-DNA structure of poly(dG-dC) poly(dG-dC) prepared in either a high salt concentration (4.0 M) or in 40 mM (Co(NH3)6)Cl3 remained invariant in the presence of berberine up to a nucleotide phosphate/alkaloid molar ratio of 0.8 and suggested that berberine neither bormd to Z-form DNA nor converted the Z-DNA to the... 

Table 6.28. 7-DIAZABICYCLOALKYLQUINOLONE ANALOGUES - STRUCTURES AND IN VITRO ACTIVITY [105]...

Thioguanine is a purine analogue structurally related to 6-mercaptopurine and azathioprine. Thioguanine interferes with several enzymes required for de novo purine synthesis, and its metabolites are incorporated into DNA and RNA, further impeding nucleic acid synthesis. The mechanism of action of thioguanine in psoriasis is not clearly understood it has been hypothesized to affect the proliferation and trafficking of lymphocytes as well as the proliferation of keratinocytes. 

White R, Malpass JR, Handa S, Baker SR, Broad LM, Folly L, Mogg A (2006) Epibatidine Isomers and Analogues Structure-Activity Relationships. Bioorg Med Chem Lett 16 5493... 

Murias M, Jager W, Handler N, Erker T, Horvath Z, Szekeres T, Nohl H, Gille L. 2005. Antioxidant, prooxidant and cytotoxic activity of hydroxylated resveratrol analogues Structure-activity relationship, Biochem Pharmacol 69 903-912. 

Shortly thereafter, two groups independently reported the synthesis of a monocyclic analogue structurally related to AP, namely, the 2,4-diamino-5-... 

Drugs that act as nucleoside analogues mimic the activity of nucleosides while lacking full function. Because nucleoside analogues structurally resemble natural nucleosides, the analogues (1) do not passively diffuse across a membrane and (2) can readily hitch a ride across the membrane by means of an ENT and/or a CNT. Several nucleoside analogues and their corresponding carrier proteins are shown in Table 3.8.14... 

Figure 2.13 Unit cell of the Prussian blue analogue structure Ma[Mb(CN)6] where the red, black, white and blue spheres represent Ma, Mb, C and N, respectively [16], Copyright (2007), with permission of Elsevier.

Figure 5.39. Molecular structures of other molecular magnetic materials. Illustrated are (a) tris(oxalato) metalates [M M (ox)3], where M I=Mn, Fe, Ni, Co, Cu, Zn M =Cr, Fe, Ru, and (b) the simplified crystal structure of Prussian Blue, with an example of the analogue structure [(tacn)8Co8(CN)i2], where the tacn ligand is 1,4,7-triazacyclononane. Reproduced with permission from (a) Min, K. S. Rhine-gold, A. L. Miller, J. S. Inorg. Chem., 2005, 44, 8433, and (b) Belttan, L. M. C. Long, J. R. Acc. Chem. Res., 2005, 38, 325. Copyright 2005 American Chemical Society.

C2-chiral bidentate fluoroarylphosphinite ligands, efficiently catalyze the asymmetric Diels-Alder reaction between enals and 1,3-dienes [36], Electronic factors apart, the catalyst creates a chiral contour that favors enal coordination, and subsequently this was extended to Ru Lewis acids [37]. These are stable at room temperature, and can be recycled almost quantitatively after the reaction. The immediate catalyst precursor, Ru(Cp)(BIPHOP-F)I is readily available via a one-pot synthesis from Ru3(CO)i2. Although the Ru-catalysts were at first not quite as active as the Fe analogues and produced lower asymmetric induction than the Fe analogues, structural data showed the way to improve the situation (Scheme 10.21). 

Kumar VA, Ganesh KN. Conformationally constrained PNA analogues Structural evolution toward DNA/RNA binding selectivity. Acc. Chem. Res. 2005 38 404-412. 

In a similar approach, very recently an imprinting procedure using labile covalent interactions was employed with quite some success [118]. Template monomer 17 was used to imprint a transition state analogue structure and to introduce at the same time a dicarboxylate moiety in the cavity. In this case a 120-fold rate enhancement compared to the solution and 55-fold compared to a control polymer containing statistically distributed dicarboxylates was observed. 

Although the pyridone structure had been deduced previously from conventional IR spectra by several authors, the reaction path is new, and appears to be plausible. The suggested mesomerism is based on the known fact that such mesomerism exists in tetrahydropyridine, which has an analogue structure ... 

W6. Williams, J. W., Duggleby, R. G., Cutler, R., and Morrison, J. F., Hie inhibition of dihydrofblate reductase by folate analogues Structural requirements for slow and tight-binding inhibition. Biochem. Pharmacol. 29, 589-595 (1980). 

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