Robert G. Shepherd

Reactivity of Azine, Benzoazine, and Azinoazine Derivatives with Simple Nucleophiles

Publisher Summary This chapter presents the reactivity pattern of azines with nucleophiles, mainly in the reactions of chloro derivatives with an anionic nucleophile (alkoxide) and with a neutral nucleophile (ammonia or aliphatic amine). The alternative mechanisms of nucleophilic substitution of aromatic compounds—namely, heteroaryne mechanism; S N 1 mechanism; ring-opening and recyclization; and synchronous or one-stage bimolecular mechanism—are also described in the chapter. The cationization of the azine–nitrogen promotes nucleophilic substitution at all positions, because the electronegativity of the nitrogen is increased. This change increases the electron deficiency (ground state) and decreases the localization energy and resistance of the π electron system to interact in the transition state with nucleophiles. The reversible interaction of the carbonyl group with an azine lone-pair facilitates substitution adjacent to the heteroatom by the anion of a β -hydroxyethyl ketone. A similar cyclic intermediate is presumably responsible for the cyclization of acetylene dicarboxylic esters with azines.

4333940 Ring-fluorinated 4-(monosubstituted-amino) phenyl compounds in inhibiting atherosclerotic lesion development

The present invention relates to the use of certain ring-fluorinated 4-(monosubstituted-amino) phenyl compounds as hypolipidemic and antiatherosclerotic agents together with their pharmacologically acceptable acid-addition and cationic salts.

Chapter 12. Synthetic Antibacterial Agents

Publisher Summary Infectious drug resistance denotes the transmission of drug resistance from one bacterium (so far only Gram-negatives) to another of the same or different strain, species, or genus. This is accomplished by conjugation that leads directly to a new recipient strain with a comparable level of resistance. The surprising facet of this phenomenon is the simultaneous transfer of resistance to an entire series of chemically and biochemically unrelated antimicrobials; most commonly in sulfanilamides, tetracyclines, streptomycin, and chloramphenicol, but also more recently penicillins, kanamycin, neomycin, nalidixic acid, and nitrofurans. Resistant bacteria can be stripped of infectious drug resistance with various acridines in vitro , albeit with low frequency; usually the method applies to all the resistance factors, but some segregation has been achieved. Several sulfanilamides and other synthetic antibacterials as well as the antibiotics are involved with infectious drug resistance. No new antibacterial screening methods are reported. Recent success in experimental animals in vitro with growing the leprosy bacillus has led to significant and promising additions in this field. Over 100 Myco leprae strains from all over the world and from the several clinical types of leprosy have now produced mouse foot-pad infections. The relationship of bacterial morphology, administration of antileprotic agents, BCG vaccination, and immune-response suppression to production of increased infectivity in mice has been studied.