Substituents and Functional Groups

Electronegative substituents, as well as carbonyl groups or other functional groups on the carbon / to a CF3 group will be seen to shield its fluorines. 

As was the case for single fluorines and CF2 groups, the deshielding of CF3 by directly bound halogen decreases in the order I Br Cl F (Table 5.1). 

//-substituted halogens shield a CF3 group, much as they did single fluorines and CF2 groups (Table 5.2). 

TABLE 5.2. Fluorine Chemical Shifts of 2,2,2-Trifluoroethyl Halides 

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Modification of Substituents and Functional Groups of Cyclic Nitronates At an ambient temperature, four-membered cyclic nitronate containing the chloronitromethyl group at the C-3 atom is gradually transformed into the corresponding acid chloride even under solvent-free conditions, and treatment of the latter with aqueous ammonia affords amide (168) (Scheme 3.119, Eq. 1). 

The organopalladium addition reactions to produce substituted olefinic compounds are very useful laboratory syntheses since a wide variety of substituents and functional groups can be present in both the organopalladium species and the olefin. The only groups which may inhibit the reaction to some extent are ones which form stable complexes with the palladium salt, such as unhindered amines. Lower yields are generally... 

Phenol is an important industrial chemical. More than 3 billion pounds are produced each year. The major uses of phenol are as a disinfectant and in the production of polymers. Complex phenols, with multiple substituents and functional groups, are common in nature, although the simple phenols are seldom encountered. 

Pteridines are widely distributed in nature and function as pigments, biological markers, and cofactors of enzymatic reactions. The oxidized heteroaromatic forms show a characteristic fluorescence which allows easy detection even in low concentrations. However, the more active 5,6,7,8-tetrahydro derivatives are nonfluorescing and oxidizable and create experimental problems in handling this type of compound. So far, all naturally occurring pteridines have turned out to be derivatives of pterin (2) and lumazine (3) which are modified by different substituents and functional groups in the 6- and/or 7-position. 

The substituted cyclopropenone acetal synthesized in Step B can be readily hydrolyzed to the corresponding cyclopropenone. This synthetic sequence provides the best and most versatile current synthetic route to substituted cyclopropenones. The deficiencies of conventional procedures are precisely the synthesis of cyclopropenones with aliphatic substituents and functional groups, for which the present method has proven to be particularly useful. ... 

III. Nomenclature of Molecules Containing Substituents and Functional Groups... 

Substituents and functional groups are indicated in the usual ways. Spiro ring systems are always numbered smaller before larger, and numbered in such a way as to give the highest priority functional group the lower position number. 

Tetraorganotin compounds are also synthesized by the hydrostannation of carbon-carbon multiple bonds effected with radical initiators (eq (134)) [129]. Although these reactions also proceed without initiator, such reactions sometimes give mixtures of regioisomers depending on the substituents and functional groups attached to carbon-carbon multiple bonds (eq (135)) [130]. 

A bicyclization strategy allows one to create a complex pattern of substituents and functional groups by the methods of acyclic synthesis. This is then transformed in the final step (Scheme 6.26) into the target with a rapid increase in complexity [100],... 

The Q[n] in its simplest form or with substituents and functional groups have potential as an aid to drug delivery by providing one or more of the following benefits ... 

There ate many reports in the literature that use this strategy and generate unsubstituted, alkyl-substituted and functionalized amino acids. Many of them ate virtually identical from a strategic viewpoint, but a variety of substituents and functional groups can be incorporated. Several examples are shown in Table 1.1. 

Synthesis problems remain, however, in providing the complete range of potentially useful polymer substituents and functional groups. One approach to this lies in the development of alternative routes to the polymers. A recent report describes a condensation-polymerization route in which alkyl substituents and, in some circumstances, mixed alkyl substituents can be introduced. 

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