Biomimetic methods

The enzymatic conversion of a-(aminomethyl)pyrroles is also used by nature to produce porphyrinogens like uroporphyrinogen III (see introduction, compound 8), which is the key building block in the biosynthesis of all known porphinoid natural products. This biomimetic method is a powerful tool for the synthesis of different porphyrins, e.g. for the preparation of JV,Af, V ,Ar"-tetramethylporphyrin-2,3,7,8,12,13,17,18-octaacetic acid dibromide 12.36... 

The above biomimetic method was successfully applied to synthesis of 2,3,8,9-tetraoxygenated fully aromatized benzo[c]phenanthridine alkaloids such as nitidine (243) (134,135), fagaronine (244) (134,135), and oxyterihanine (242) (136) (Scheme 42). The former two alkaloids attract many synthetic... 

As we increasingly understand the chemistry performed by living systems, in particular that catalyzed by enzymes, we will continue to develop biomimetic methods to achieve some of the special selectivities that enzymes show. Enzymes can selectively bind a particular molecule out of the mixture of substances in the cell, then hold it in such a way that the geometry of the enzyme-substrate com-... 

A biomimetic method using a cyclic dipeptide (39) is available. In the presence of HCN in toluene containing 2mole% of (39), benzaldehyde is converted into the (/ )-cyanohydrin in 97% yield (97% cc)1 lfi. ... 

Recently, attempts have been made to develop biomimetic methods, simulating plant uptake of metals. An example of such a method is DGT (diffusive gradients in thin films), developed by Zhang et al. (2001), for measuring metal availability to plants. In this case, metal accumulation in a chelex layer is measured. By taking into account thickness of the diffusive layer covering the chelex layer and contact time with the soil sample, it is possible to estimate the available metal concentration in the soil solution. The DGT method may also be used to estimate metal speciation in surface water (Zhang 2004). 

Similar biomimetic methods have been developed for assessing the (bio)avail-ability of organic chemicals in water, sediments, and soil (Mayer et al. 2003 Ter Laak et al. 2006). The main advantage of these nondepletion techniques, such as the solid-phase microextraction methods (SPMEs), is that they may be used without disturbing the chemical distribution in surface water or soils or sediments. 

A biomimetic method was developed by Arnoldi and coworkers to synthesize propacin (31). Oxidation of an equimolar mixture of 35 and isoeugenol in toluene/ methanol with Ag20 at room temperature provided 30% of 31. A similar reaction has also been attempted with coniferyl alcohol (45) to synthesize 9 and 10 (72). 

Zachary Hilt JZ. Nanotechnology and biomimetic methods in therapeutics Molecular scale control with some help from nature. Adv. Drug Deliv. Rev. 2004 56 1533-1536. 

The dimeric phenanthrenes agrostonin (421), agrostonidin (422) [193], reptanthrin and isoreptanthrin (418, 419) [194] have been regioselectively synthesized from their respective biomimetic methods involving oxidative coupling with PM A on a silica gel surface. 

Xie, J. and Luan, B.L.. Eormation of hydroxyapatite coating using novel chemo-biomimetic method.. 1. Mater. Sci. Mater. Med.. 19. 3211, 2008. 

Bharati, S., Sinha, M.K., and Basu, D. (2005) Hydroxyapatite coating by biomimetic method on titanium alloy using concentrated SBF. Bull. Mater. Sci., 28 (6), 617-621. 

L. (2005) Nanocrystalline hydroxyapatite coatings on titanium a new fast biomimetic method. Biomaterials, 26 (19), 4085 -4089. 

A.H., and Bressiani, J.C. (2008) Hydroxyapatite coating on silicon nitride surfaces using the biomimetic method. Mater. Res., 11 (1), 47-50. 

M. V. (2012) Biomimetic Method for Coating Micro and Macroporous Titanium Substrates, Biocell, 36(1 ) A5, No. 12. 

Toparli, M., Pasinli, A., Yildiz, H., Celi, E. and Aksoy, R.S. (2010) Synthesis of hydroxyapatite coatings on Ti6A14V substrate by biomimetic method, Proc. 2nd Int. Symp. 

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