Benzylic substituted nicotinamides

It was shown that dibenzothiophene oxide 17 is inert to 1-benzyl-l,4-dihydro nicotinamide (BNAH) but that, in the presence of catalytic amounts of metalloporphyrin, 17 is reduced quantitatively by BNAH. From experimental results with different catalysts [meso-tetraphenylporphinato iron(III) chloride (TPPFeCl) being the best] and a series of substituted sulfoxides, Oae and coworkers80 suggest an initial SET from BNAH to Fe1 followed by a second SET from the catalyst to the sulfoxide. The results are also consistent with an initial coordination of the substrate to Fem, thus weakening the sulfur-oxygen bond in a way reminiscent of the reduction of sulfoxides with sodium borohydride in the presence of catalytic amounts of cobalt chloride81. 

A novel electron transfer free radical mechanism has been elucidated for sodium naphthalenide induced demercuration. A new reductant for the cleavage of the C—Hg bond, A -benzyl-1,4-dihydro-nicotinamide (BNAH), has also been proposed it reduces alkylmercury(II) acetates via an electron transfer chain substitution mechanism. ... 

The inhibitory power of iV-alkyl nicotinamide derivatives has been found to increase with increasing length of the alkyl chain 1,436,438-443). These results indicate that there is a hydrophobic binding area close to or actually in the substrate binding site, provided the nicotinamide moiety of these derivatives and of the coenzyme molecule bind to the same site on the enzyme. Similar results were found for iV-alkyl-substi-tuted ammonium chlorides 441,443)- Substitution of the amino group by a carboxyl group in AT-benzyl-3-aminopyridinium chloride reduces the inhibition 443)-... 

Phenoxypyridinecarbonamides are surprisingly flexible, when the pyridine ring is substituted (review in Refs. [27, 34]). The first active pattern consisted of nicotinamides with a 2-phenoxy substitution (3, Fig. 4.1.4). For the latter, the m-position (R ) was important with 3-CF3 and 3-Cl being most active, while double substitution led to a decrease of activity. While small substituents R such as H or CH3 gave good herbicidal activity, Br or Cl were weaker. In the amide part, N-phenyl and N-benzyl derivatives showed comparable activity ethylene as a spacer... 

Within a molecule of NAD(P)H, the 1,4-dihydronicotinamide moiety acts as a reducing reagent. Thus, a 1,4-dihydropyridine derivative where the ring nitrogen is substituted by a simple substituent, such as 1-propyl-1,4-dihydronicotinamide (PNAH), 1-benzyl-1, 4-dihydro-nicotinamide (BNAH), or Hantzsch ester (HEH), can be considered as a model compound for NAD(P)H. 

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