It was shown that reaction of trehalose with 1 equiv of a fatty acid in pyridine promoted by 1 equiv of the uronium-based coupling agent 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU) at room temperature gives a good yield of the primary ester accompanied by small amounts of the diprimary ester using hexanoic, palmitic, and oleic acids as examples. Reactions using 2 equiv of the fatty acids gave the symmetrical diesters. The monoesters were reacted with different fatty acids to give nonsymmetric 6,6'-diesters in very good yields. Compounds synthesized include the most abundant component of the very complex maradolipid mixture, 6-O-(13-methyltetradecanoyl)-6'-O-oleoyltrehalose, and a component potentially present in this mixture, 6-O-(12-methyltetradecanoyl)-6'-O-oleoyltrehalose, a derivative of an ante fatty acid. The C5-C6 rotameric populations of 6-O-monoesters, symmetrical 6,6'-diesters, and 2,6,6'-triesters of fatty acids were calculated from the values of the H5-H6R and H5-H6S coupling constants and found to be similar to those found for glucose. The rotameric populations of the monosubstituted glucose residues in the 2,6,6'-triesters was altered considerably to favor the gt rotamer, presumably because of attraction between the 2- and 6'-fatty acid chains.

A novel two-step procedure involving the formation of 1-arylidene-2-tetralones from 2-tetralone and subsequent Michael addition of a cyclic secondary amine on the alkenone followed by in situ aerial oxidation was developed to produce 2-naphthol Mannich bases. A simple microwave-assisted one-pot synthesis of 2-naphthol Mannich bases was also carried out under solvent-free conditions from 2-naphthol and corresponding aldehydes and amines in the presence of p-toluenesulfonic acid. The compounds of this series displayed interesting NMR behaviour. Extensive variabletemperature NMR investigations, including HSQC experiments, are herein reported. NMR results on the conformation in solution phase were found to be consistent with the X-ray crystal structure in the solid state.Résumé : On a mis au point une nouvelle méthode en deux étapes qui permet de produire des bases de Mannich du 2-naphtol et qui implique la formation de 1-arylidène-2-tétralones à partir de la 2-tétralone, puis une addition subséquente de Michael d'une amine secondaire cyclique sur l'alcénone, suivie d'une oxydation in situ par de l'air. On a aussi réa-lisé une synthèse des bases de Mannich du 2-naphtol par une simple réaction monotope du 2-naphtol, des aldéhydes et des amines correspondants en présence d'acide p-toluènesulfonique, sous l'effet de micro-ondes, dans des conditions sans solvant. Les composés de cette série présentent des comportements RMN intéressants. On a effectué de nombreuses études RMN à température variable, y compris des expériences de « HSQC ». On a trouvé que les résultats de la RMN sur la conformation en solution sont en accord avec la structure cristalline déterminée par diffraction des rayons X, à l'état solide.Mots clés : bases de Mannich, réaction de Mannich assistée par les micro-ondes, spectroscopie RMN à température variable, dynamique RMN, cristallographie par diffraction des rayons X.[Traduit par la Rédaction] Jha et al. 853

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Simple strategies for the synthesis of five series of cationic gemini surfactants and one series of zwitterionic gemini surfactants from pentaerythritol have been developed. Two lipophilic groups were introduced onto pentaerythritol by alkylation of the known compound, O-benzylidenepentaerythritol, with 1-bromooctane, 1-bromodecane, 1-bromododecane, and 1-bromotetradecane. Hydrogenolysis of the benzylidene acetals gave diols which were converted into three different series of trimethylammonium derivatives. The diiodides derived from the diols could be displaced by dimethylamine, even though they are adjacent to a quaternary carbon atom. Alkylation with methyl iodide gave the first series. The iodides were easily displaced by cyanide ion and the resulting dinitriles were hydrolyzed, converted to N,N-dimethylamides, and reduced to give a second series. Oxidation of the diols to dialdehydes under Swern conditions followed by Horner−Wadsworth−Emmons reactions with diethyl N,N-dimethylcarbamoylmethylphosphonate followed by two-stage reduction gave a third series. The dialkoxides derived from the four di-O-alkylpentaerthritol diols were reacted with 2-dimethylaminoethyl chloride and 3-dimethylaminopropyl chloride in neighboring-group assisted double Williamson ether syntheses to give precursors to two more series. As expected because the neighboring group participation occurs through a four-membered-ring intermediate, considerably more vigorous conditions were required for the reactions with 3-dimethylaminopropyl chloride. 2-Diethylaminoethyl bromide was found to be less reactive than 2-dimethylaminoethyl chloride. The products were alkylated with methyl iodide and, in some cases, other alkyl halides to give cationic gemini surfactants. Alkylation of one series with ethyl bromoacetate followed by anion exchange resin catalyzed ester hydrolysis gave zwitterionic gemini surfactants. The members of all series have superior surfactant properties.

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Syntheses of highly mannosylated polyester dendrimers with 2, 4, 8, and 16 α-D-mannopyranose residues on their peripheries connected by different linker arms are presented. Attractive features of these systems as potential inhibitors of uropathogenic Escherichia coli (UPEC) include the use of nontoxic and biocompatible polyester dendrimer backbones, aglycones whose lengths are designed to fit in the tyrosine gate, and multiple copies of α-linked D-mannopyranose residues, capable of effectively binding to the exposed mannose-sensitive type 1 pili on UPEC's outer surface.

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This work describes a convenient one-pot procedure for the synthesis of 2,2-disubstituted 2,3-dihydro-1H-naphtho[2,1b]pyrans {i.e. 2,2-disubstituted 1H-benzo[f]chromans} by the reaction of 2-tetralones and a,a-disubstituted b-hydroxy propionaldehydes under acidic conditions.