Biological activity nucleophilic substitution

Many 2-substituted 5-nitrothiazoles are prepared (by nucleophilic substitution reactions on 2-halogeno-5-nitrothiazoles) for use as biocides or for their biological activity (31, 91-95). 

Pyrido[2,3-d]pyridazine, 1 -chloro-4-hydrazino-biological activity, 3, 261 Pyrido[2,3-(i]pyridazine, 4-chloro-l-hydrazino-biological activity, 3, 261 Pyrido[2,3-(i]pyridazine, 5,8-dichloro-nucleophilic substitution, 3, 242 Pyrido[2,3-(i]pyridazine, polyhalo- H NMR, 3, 234... 

Pyrido[3,4-d]pyrimidine-2,4-dione synthesis, 3, 215 Pyridopyrimidines, 3, 201 iV-alkylations, 3, 206 biological activity, 3, 260-261 1-electron reductions, 3, 207 IR spectra, 3, 204 mass spectra, 3, 204 MO calculations, 3, 204 NMR, 3, 202, 203 nucleophilic substitution, 3, 213 8-nucleosides synthesis, 3, 206 physical properties, 3, 201-205 protonation, 3, 206 radical reactions, 3, 215 reactions with water, 3, 207 reduced... 

A typical second step after the insertion of CO into aryl or alkenyl-Pd(II) compounds is the addition to alkenes [148]. However, allenes can also be used (as shown in the following examples) where a it-allyl-r 3-Pd-complex is formed as an intermediate which undergoes a nucleophilic substitution. Thus, Alper and coworkers [148], as well as Grigg and coworkers [149], described a Pd-catalyzed transformation of o-iodophenols and o-iodoanilines with allenes in the presence of CO. Reaction of 6/1-310 or 6/1-311 with 6/1-312 in the presence of Pd° under a CO atmosphere (1 atm) led to the chromanones 6/1-314 and quinolones 6/1-315, respectively, via the Jt-allyl-r 3-Pd-complex 6/1-313 (Scheme 6/1.82). The enones obtained can be transformed by a Michael addition with amines, followed by reduction to give y-amino alcohols. Quinolones and chromanones are of interest due to their pronounced biological activity as antibacterials [150], antifungals [151] and neurotrophic factors [152]. 

IV-acyloxy-iV-alkoxyamides, biological activity, 97-115 anticancer activity of, 115 mutagenicity of, in Ames Salmonella/ microsome assay, 97-115 IV-acyloxy-iV-alkoxyamides, chemical reactivity, 59-96 factors contributing, 59-60 nucleophilic substitution reactions, see Nucleophilic substitution reactions solvolysis studies, see Solvolysis... 

Thus, Af-acyloxyl-A-alkoxyl substitution in these anomeric amides significantly impacts upon their biological activity in two ways Inversely by affecting the ease of their nucleophilic reactivity towards intracellular bionucleophiles and hence their intracellular survival, and directly by controlling their ability to undergo Si 2 reactions once ultimately bound in the major groove of DNA. 

In continuation of our investigations on asymmetric nucleophilic acylations with lithiated a-aminonitriles [40], we envisaged the asymmetric synthesis of 3-substituted 5-amino-4-oxo esters A, bearing both a-amino ketone and 5-amino ester functionalities (Scheme 1.1.14) [41]. Since a-amino ketones are precursors of chiral p-amino alcohols [42, 43] and chiral amines [43], their asymmetric synthesis has the potential to provide valuable intermediates for the synthesis of biologically active compounds, including peptidomimetics [44]. The retrosynthetic analysis of A leads to the a-aminoacyl carbanion B and p-ester carbocation... 

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