Functional groups. See

Acrolein, acrylamide, hydroxyalkyl acrylates, and other functional derivatives can be more hazardous from a health standpoint than acryhc acid and its simple alkyl esters. Furthermore, some derivatives, such as the alkyl 2-chloroacrylates, are powerful vesicants and can cause serious eye injuries. Thus, although the hazards of acryhc acid and the normal alkyl acrylates are moderate and they can be handled safely with ordinary care to industrial hygiene, this should not be assumed to be the case for compounds with chemically different functional groups (see Industrial hygiene Plant safety Toxicology). 

For a review of selective reduction of aliphatic nitro compounds without disturbance of other functional groups, see Ioffe, S.L. Tartakovskii, V.A. Novikov, S.S. Russ. Chem. Rev., 1966, 35, 19. 

More extensive work has been done to develop the UNIFAC method, to include a wider range of functional groups see Gmeling et al. (1982) and Magnussen et al. (1981). 

T3 1 solvent modifier. with ionic functional groups. (See also Section 19.6.2). peptides, nucleic acids, proteins. Saccharides. 

The aromatic hydrocarbons contain at least one unsaturated ring system with the general structure C6R6, where R is any functional group (see Chap. 1). The parent hydrocarbon of this class of compounds is benzene (C6H6), which exhibits the resonance, or delocalization of electrons, typical of unsaturated cyclic structures. Owing to its resonance energy, benzene is remarkably inert. 

Before proceeding to the heuristic classification of functional groups by Evans, it is as well to remember here that in classical organic chemistry when the heteroatom that determines the functionality is attached to an sp carbon atom, this atom is usually not included as forming part of the functional group. However, if the heteroatom is attached to an sp or sp carbon atom, then in these cases the carbon atoms are included in the functional group (see Table 2.1). 

A reaction in which one functional group (see p.lO) is replaced by another is termed substitution. Depending on the process involved, a distinction is made between nucleophilic and electrophilic substitution reactions (see chemistry textbooks). Nucleophilic substitutions start with the addition of one molecule to another, followed by elimination of the so-called leaving group. 

Note 1 A MCPLC is formed by linking together suitable relatively rigid units directly or through appropriate functional groups (see Fig. 33). 

Templates based on tetrahedral carbon provide an additional advantage as they can be further extended with additional functional groups (see Section VI). 

The toxicity of the paraffins is altered with the substitution of functional groups see figure 6.15. The ranking of the toxicity of the methyl derivatives is... 

Alcoholysis of nitriles, of ortho and thio ortho esters (transesterification), and of halides is the most common method of preparing the ortho ester functional groups (see Eqs. 2-7). A less practical method is the addition of alcohols to ketene acetals. The latter method is used only when the other methods are not found applicable to the synthesis of specially substituted mixed ortho esters. 

Note that some reactions are reversible (indicated by . "), whereas others are irreversible under environmental conditions. The dotted arrow indicates that, in principle, a reaction is possible, but no clear evidence exists showing that the reaction proceeds abiotically in the dark. b For oxidation states of nitrogen in various functional groups see Table 2.5. c For oxidation states of sulfur in various functional groups see Table 2.6. 

A complex chain of about 60 carbon atoms with a variety of functional groups (see text)... 

Alkynes, also known as acetylenes, have a carbon-carbon triple bond functional group (see Figure 11.14). Alkynes are relatively rare in medical settings, so we present them only for the sake of completeness. The simplest alkyne is ethyne, which is more commonly known as acetylene. Alkynes are named by adding the suffix -yne and following the normal IUPAC rules. 

One of the major drawbacks of the diazoacetyl group was its instability at low pH and its reactivity in the dark towards protein functional groups (see Section 4.7.2). The 2-diazo-3,3,3-trifluoropropionyl and p-toluenesul-fonyldiazoacetyl groups are considerably improved in these respects and are stable in 1 M hydrochloric acid. 

To this point, various physicochemical properties of drugs such as lipophilicity, ionization, and partition coefficient have been discussed. While these are certainly major factors, there is an additional factor that can influence drug distribution, namely chirality. Chirality is a relatively unique structural characteristic of certain molecules that can exist in two asymmetric, nonsuperimposable isomers (enantiomers) due to the presence of a chiral center (a carbon atom that is attached to four different functional groups (see Chapters 5 and 13). 

A dimensionless molecular retention index Me parameter can be defined as the sum of Mr (relative molecular weight) and a structural increment W. Contained in W are all the additive contributions of the functional groups (see Eq. 4-52) which differ from a hypothetical n-alkane with the same Mr value. According to definition, the W values of the n-alkanes are always equal to zero. In this manner it is possible to estimate the partition coefficients of any given organic compound between a gas and any given liquid or polymer with help of additive structural increments. 

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