Reactions involving phenol derivatives and acyl chlorides have to be controlled for competitive O-acylations and C-acylations (Friedel-Crafts acylations and Fries rearrangements) in acidic condition. The extent for these reactions in tri fluoromethanesulfonic acid (TfOH), which is used as catalyst and solvent, is examined. Although diluted TfOH was needed for effective Oacylation, concentrated TfOH was required for effective C-acylations in mild condition. These results have been applied to the novel synthesis of homotyrosine derivatives. Both Fries rearrangement of N-TFA-Asp(OBn)-OMe and Friedel-Crafts acylation of phenol with N-TFA-Asp(Cl)-OMe in TfOH afforded the homotyrosine skeleton, followed by reduction and deprotection afforded homotyrosines maintaining stereochemistry of Asp as an optically pure form.

Saccharin is one of the most common artificial sweeteners that has a bitter taste at high concentrations. Currently, there are no detailed functional analyses of these gustatory receptors. Therefore, we designed and synthesized photoreactive saccharin derivatives that contain a (trifluoromethyl) diazirinyl moiety at the 5- or 6-position for use as functional analysis tools for photoaffinity labeling

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Photoaffinity labeling is a reliable analytical method for biological functional analysis. Three major photophores--aryl azide, benzophenone and trifluoromethyldiazirine--are utilized in analysis. Photophore-bearing L-phenylalanine derivatives, which are used for biological functional analysis, were inoculated into a Klebsiella sp. isolated from the rhizosphere of a wild dipterocarp sapling in Central Kalimantan, Indonesia, under nitrogen-limiting conditions. The proportions of metabolites were quite distinct for each photophore. These results indicated that photophores affected substrate recognition in rhizobacterial metabolic pathways, and differential photoaffinity labeling could be achieved using different photophore-containing L-phenylalanine derivatives.

As the 1'-hydroxyl group of sucrose is well known to be less reactive than other primary alcohols, there are no reports on the substitution of a phenoxy group at this position. Chemo-enzymatic synthesis of photoreactive 1'-phenoxy-substituted sucrose was examined to elucidate the functional analysis of sweet receptors.

Biotin is one of the most useful tags in (bio)analytical science due to its specific interaction with avidin, but is not easy to convert because of its low solubility in most solvents. Friedel-Crafts acylation of biotin acid chloride in triflic acid was examined, and the synthesized derivatives had stronger affinity to avidin than biotin in a binding assay using 2-(4'-hydroxyphenylazo)benzoic acid

Labeling. -The stereocontrolled Friedel-Crafts benzoylation of chiral phenylalanine derivatives is described. The products can be used in photoaffinity labelling studies. The photolysis of (VIII) is reported. -(MURAI, Y.; WANG, L.; MUTO, Y.; SAKIHAMA, Y.; HASHIDOKO, Y.; HATANAKA, Y.; HASHIMOTO*, M.; Heterocycles 87 (2013) 10, 2119-2126, http://dx.doi.org/10.3987/COM-13-12815 ; Grad. Sch. Agric., Hokkaido Univ., Kita, Sapporo 060, Japan; Eng.) -M. Bohle 06-082

Simple Deuterium Introduction at α-Position of Carbonyl in Diazirinyl Derivatives for Photoaffinity Labeling. -Deuterium incorporation into diazirinyl acetophenone derivative (I) proceeds at the α-position of the carbonyl group without decomposition of the diazirinyl ring. Additional deuterium can be introduced by reduction of the benzyl carbonyl and subsequent treatment with triethylsilane-D-TFA. Similarly, subjecting diazirinyl fatty acid derivative (V) to H/D exchange reactions proceeds in a selective fashion. Methyl ester (VII) is hydrolyzed without loss of deuterium. -(MURAI, Y.; TAKAHASHI, M.; MUTO, Y.; HATANAKA, Y.; HASHIMOTO*, M.; Heterocycles 82 (2010) 1, 909-915, http://dx.doi.org/10.3987/com-10-s(e)57 ; Grad. Sch. Agric., Hokkaido Univ., Kita, Sapporo 060, Japan; Eng.) -H. Hoennerscheid