Natural biologically active reviews

Proteins, enzymes, polysaccharides, and nucleic acids are natural biologically active polymers, but no attempt will be made to review these diverse systems here several recent books and review articles are available.20-22,58-60 synthetic analogs have been prepared of essentially every type of natural macromolecule and many of these have exhibited biological activity. These analogs will be considered briefly in the next several sections. 

For general and comprehensive reviews on applications of organocatalysis in the synthesis of natural products and non-natural biologically active molecules (2000-2009), see (a) de Figueiredo, R.M. and Christmann, M. (2007) Eur.J. Org. Chem., 2575-2500 (b) Marques-Lopez,... 

This review deals with methods for the synthesis of 1,2,4-triazine mono-lV-oxides and their reactivity. The interest in 1,2,4-tiiazines is due to their incorporation in many natural and artificial compounds, their biological activity, and other useful properties. 

Kozubek, A., Tyman, J. Resorcinolic lipids, the natural non-isoprenoid phenolic amphiphiles and their biological activity. Chemical Reviews, Vol.99, No.l. Qanuary 1999), pp. 1-31, ISSN 0009-2665... 

Tietze, L.F. 8c Modi, A. (2000) Multicomponent Domino Reactions for the Synthesis of Biologically Active Natural Products and Drugs. Medical Chemical Reviews, 20, 304-322. 

Metal complexes of ligands containing a sulfur donor in conjunction with nitrogen, oxygen or a second sulfur have been reviewed in the past [11-13]. For example, reviews of the coordination compounds of dithiophosphates [14], dithiocarbamates [15, 16], dithiolates [17], dithiodiketonates [18], and xanthates [16] have appeared. The analytical aspects [19] and the spectral and structural information of transition metal complexes of thiosemicarbazones [20, 21] have been reviewed previously. Recent developments in the structural nature of metal complexes of 2-heterocyclic thiosemicarbazones and S-alkyldithiocarbazates, depicted below, are correlated to their biological activities. 

The ocean is a rich source of natural products, and their structural variety has inspired numerous chemists and chemical ecologists. Comprehensive reviews exist on the structure and occurrence, biosynthesis, and biological activity of marine natural products (see, e.g., [ 1-5]). An excellent book published in 2001 that deals exclusively with marine chemical ecology highlights different aspects of chemical communication and chemical defense [6]. It would be impossible to cover all aspects of chemical defense in this environment, and thus this contribution will focus on a few selected aspects that have been under intense research and discussion in recent years. 

Versatile uses of nitrile oxides in organic synthesis up to year 2000 are well reviewed by Jaeger and Colinas (5). Therefore, this subsection is limited to data published after 2000 with the exclusion of those cited in Reference 5. The contents of the subsection are organized by taking into account the chemical stmcture (Sections 1.4.1.1 and 1.4.1.2), natural origin of parental compounds (Section 1.4.1.3), and biological activity of synthesized compounds (Section 1.4.1.4). 

Catalytic hydrogenation of polycyclic fused nitroso acetals is a more complex reaction sequence. This process was successfully used in the synthesis of natural and biologically active compounds (see, e g., Refs. 148, 367 and the review 99). 

Since the origin, the most efficient source of drugs and biological active molecules is Nature. As reported by Newman and Cragg in a recent review [1], at least 25-30% of New Chemical Entities (NCE) going under study for pharmaceutical and clinical applications are primarily derived from Nature (N) or Natural Derived (ND), while only 30% are merely synthetic, as reported in Figure 2. 

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