Small-molecule compounds 234 INDEX

A number of combinatorial-based syntheses have been reported. Andrus et al. prepared a solution-phase indexed combinatorial library of nonnatural polyenes such as 291 for multidrug resistance reversal.298 This library was formed by modification of R and R. Ellman and co-workers reported a combinatorial library of synthetic receptors targeting vancomycin-resistant bacteria,209 and Paterson et al. prepared polyketide-type libraries by iterative asymmetric aldol reactions on solid support.2l0 Rieser et al. used combinatorial liquid-phase synthesis to prepare [1,4]-oxazepine-7-ones by the Baylis-Hillman reaction (see sec. 9.7.B).2H Schreiber and co-workers reported the synthesis and evaluation of a library of polycyclic small molecules for use in chemical genetic assays.2 2 Bauer et al. reported a library of N-substituted 2-pyrazoline compounds... 

Essential oils are concentrated extracts or steam distillates of aromatic plants. Oils such as wintergreen or jasmine have been added to enhance the flavor and smell of food for centuries and are key components of perfumes. Chemical analysis of these oils reveals that the overall smell is due to complex mixtures of small molecules, many of which contribute to the smell of the oil. Indole and indolic compounds are common components of these mixtures. Natural jasmine oil typically contains about 2.5% indole. Over time, the increasing cost of raw materials and processing has led to efforts to produce simpler nfixtures that would have the same sensory effect. Reasonable approximations of many of these oils can be made today with completely synthetic components. Despite these advances, the imporl/export market for natural essential oils in 2008 still was a respectable 2.5 billion (See PDF download from http //www.cmm.org/index.php optiOTi=com docman task). 

Center for Biotechnology Information (NCBI) and provides information on the biological activity of small molecules in three databases Substances, Compounds, and BioAssays. As of this writing, there are about 120 million substances and 48 million compounds indexed at the site, as well was over 710 million bioassays for the compounds in the compound database. Compounds are identified by name or structure, while subtances may include mixtures of compounds, such as plant extracts. It is generally more useful to search the compound index by name or structure. 

The tendency towards explosive decomposition noted for dihalo-2,4-hexadiyne derivatives appears to be associated more with the co-existence of halo- and acetylene functions in the same molecule, than with its being a polyacetylene. Haloacetylenes should be used with exceptional precautions [1], Explosions may occur during distillation of bromoacetylenes when bath temperatures are too high, or if air is admitted to a hot vacuum-distillation residue [2], Precautions necessary in isolating and handling such compounds on the small (1 g) scale are detailed [3], Individually indexed compounds are ... 

An alternative method for assessing cell layer integrity is through the use of hydrophilic paracellular transport markers (e.g., radiolabeled D-mannitol or fluorescein-Na+), which passively traverse cells by the paracellular route. Small amounts of compound required for in vitro conjunctival cell culture transport experiments make this approach well suited for screening purposes. Relative absorption index of a series of pharmacologically active molecules can be ranked against known markers for the identification of candidates with potential absorption problems, which is a reliable tool to select drug candidates with optimal characteristics. 

Refractive indexes of these systems are given in Fig. 3 and in Tables 10-13, They all show positive deviations from additivity in volume fractions of the components, which increase in the order nitrobenzene < m-nitroi oluene < o-nitrotoluene. This confirms that the addition compounds formed by these aromatic nitrocompounds with sulphuric acid are more and more stable in this order, which is the order of increasing basicities. Rathex unexpectedly, however, the system with nitromethane shows high positive deviations from additivity, which equal those in the system with. o-nitrotoluene, This fact might be due to the small dimensions of the nitromethane molecules, which are therefore Jess likely to cause the disruption of the structure of sulphuric acid and thus U lower the Tefractive indexes of the mixtures, than the larger molecules of the aromatic nitrocompounds. 

---