Dynamics of endoergic aromatic substitution reactions

Quantum Chemical Studies of Aromatic Substitution Reactions

In this thesis, density functional theory (DFT) is used to investigate the mechanisms and reactivities of electrophilic and nucleophilic aromatic substitution reactions (SEAr and SNAr respectively). For SEAr, the σ-complex intermediate is preceded by one (halogenation) or two (nitration) π-complex intermediates. Whereas the rate-determining transition state (TS) for nitration resembles the seco...

BENZYNE AS AN INTERMEDlATE IN NUCLEO - PHILIC AROMATIC SUBSTITUTION REACTIONS

IT sometimes happens in organic chemistry that a large body of related fact accumulates which seemingly cannot be rationalized on the basis of the currently available theoretical concepts. In such circumstances, substantial clarification may often be achieved by an approach which is novel only in application .to the system at band. The pieces of the puzzle may then fall into place and experimen...

Regioselective Electrophilic Aromatic Substitution Reactions over Reusable Zeolites

Zeolite catalysts can play an important role in the development of greener organic syntheses through their abilities to act as heterogeneous catalysts, support reagents, entrain by-products, avoid aqueous work-ups and enhance product selectivities via shape-selectivity. We have shown that zeolites under modest conditions can have advantages in para-regioselective nitration, alkylation, acylatio...

Modern Nucleophilic Aromatic Substitution

Utility of certain nucleophilic aromatic substitution reactions for the assay of pregabalin in capsules

BACKGROUND Pregabalin (PG) is an anticonvulsant, analgesic and anxiolytic drug. A survey of the literature reveals that all the reported spectrophotometric methods are either don't offer high sensitivity, need tedious extraction procedures, recommend the measurement of absorbance in the near UV region where interference most probably occurs and/or use non specific reagent that don't offer suita...