Exchanges substitutions

S W A R T S Halogen exchange Substitution of chlonne atoms with Huorine atoms by means of SbFs... 

The above considerations do not necessarily apply to reactions of electrophilic reagents with pyrazole and imidazole anions (134, 135). The imidazole anion is sometimes (diazo coupling, halogenation, deuterium exchange) substituted in the 2-position (139) and the indazole anion in the 3-position (cf. Section 3.4.1.4.5). 

The processes of exchange (substitution) of acids and bases are similar [Schemes (1-3) (1 -5)] ... 

Olefin exchange (substitution of H atoms of the olefin by D atoms)... 

SWARTS Halogen exchange Substitution ol chlorine atoms with fluorine atoms by means ol SbFs... 

Fig. 3. Active positions for H—D exchange. [ Substitution at these positions is most likely acid catalyzed (29)]...

The primary forms are elementary tritimn or tritiated water. All methods of labelling with tritium involve ultimately either exchange, substitution or addition reactions. A niunber of these reactions are shown in Fig. 3. The primary labelling processes are as follows. 

Kricheldorf, H.R., Al-Masri, M., and Schwarz, G. (2002) Macrocycles. 20. Cyclic polyfethylene glycol) phthalates via ring-exchange substitution. Macmmolecules, 35,8936-8942. 

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