Tokuji Takeda

Preparation, surface-active properties and acid decomposition profiles of a new “soap” bearing a 1,3-dioxolane ring

New soap-type surfactants bearing a 1,3-dioxolane ring were prepared in good yields by the acid-catalyzed condensation of 1-O-alkylglycerols (alkyl: decyl, dodecyl, tetradecyl, heptadecyl, octadecyl, orcis-9-octadecenyl) with oxocarboxylic acid esters, followed by alkaline hydrolysis without any expensive reagent and special equipment. These surfactants were soluble in alkaline water at room temperature. Their critical micelle concentrations were much smaller than that of sodium dodecanoate. An alkaline solution of the octadecyl homologue was nonfoaming, but the other homologues, including thecis-9-octadecenyl derivative, showed high foaming ability in alkaline solutions. The structural effect of these compounds on the area per molecule at the surface is also discussed. Because these surfactants contain a 1,3-dioxolane ring, they can be utilized as a new acid-decomposable type of cleavable surfactant. At pH 1, they decompose almost completely into nonsurface-active species after 80 min.

Synthesis and properties of destructible anionic and cationic surfactants with a 1,3-dioxolane ring

A convenient synthetic method for the preparation of destructible surfactants containing a 1,3-dioxolane ring with various substituents is described. The substituents include carboxylate, quaternary ammonium, and several aliphatic alkyl groups, such as hydrophilic or hydrophobic groups. These novel surfactants had good surface activity, and were easily hydrolyzed under acidic conditions. They also catalyzed aliphatic halide substitution.

Biodegradation of different carboxylate types of cleavable surfactants bearing a 1,3-dioxolane ring

The biodegradability of new carboxylate types of “acid-sensitive” cleavable surfactants bearing a 1,3-dioxolane ring was measured by the biochemical oxygen demand (BOD) method in the presence of activated sludge. The result for sodium dodecanoate, measured under the same conditions, was used as a standard for evaluating the biodegradability of these cleavable surfactants. For cleavable surfactants derived from epoxides and oxocarboxylates, the biodegradation was considerably influenced by the length of the lipophilic alkyl chain, the presence of the oxymethyl moiety in the lipophilic group, and the number of methylene units between the dioxolane ring and the carboxylate group. For another type of cleavable surfactant, 2-(long-chain alkyl)-1,3-dioxolane-4,5-dicarboxylate, the biodegradation rate for the compound, bearing a proton at position 2 in the dioxolane ring, is faster than that for the corresponding compound bearing a methyl group at position 2.

Enantioselective complexation of chiral linear hosts containing monosaccharide moieties with chiral organic amines

Abstract New chiral linear hosts ( 1–3 , a : peracetylated derivatives, b : permethylated derivatives) containing monosaccharide end groups were designed on the basis of the structural features of permethylated 1F-fructonystose (MeFruNys), which shows a remarkable chiral discrimination ability, and then synthesized. The chiral discrimination ability of their hosts toward chiral organic ammonium guests were evaluated using FAB mass spectrometry and 1H NMR. Their hosts showed chiral discrimination for some guests. As the contrasting compounds ( 4 and 5 ) hardly showed any chiral discrimination, it was clarified that the structural features extracted from MeFruNys are very significant factors for chiral recognition. The 1H NMR shift induced by adding a potassium ion (counter anion: SCN−) in (CD3)2CO suggested that the cation moiety of the chiral guests was located at the binding site consisting of the –O–C–C–O– units and the ring-oxygens of the saccharide moieties. The structure of the complex of host 1b with 1-(1-naphthyl)ethylammonium ion (NEA+) was estimated by the 1H NMR induced shifts and the molecular dynamics simulation.

Facile ee-determination from a single measurement by fast atom bombardment mass spectrometry: a double labeling method

Abstract From a single fast atom bombardment mass spectrum, the optical purity (enantiomeric excess: ee ) of chiral organic primary and secondary amine salts (guests) such as tryptophan 2-propyl ester hydrochloride and proline 2-propyl ester hydrochloride was easily determined with a high accuracy using both the deuterium-labeled/unlabeled enantiomeric host pair (DD-Gal2deg and LL-Gal2deg-d 24 ) and the corresponding deuterium-labeled internal standard guest (for example, the S -amino acid ester-d m salt).

Combinatorial evaluation of the chiral discrimination of permethylated carbohydrates using fast-atom bombardment mass spectrometry

The chiral discrimination abilities of several variously permethylated carbohydrates toward various amino acid 2-propyl esters were combinatorially evaluated from the relative peak intensity of the 1:1 diastereomeric complex ions with the deuterium-labeled L-amino acid 2-propyl ester protonated ion and with the unlabeled D-amino acid 2-propyl ester protonated ions in FAB mass spectrometry. The chiral discrimination abilities evaluated using FAB mass spectrometry approximately corresponded to the ratio of the association constants (K(R)/K(S)) toward each enantiomer in the solution. Therefore, this evaluation method is very useful for the screening of the chiral discrimination abilities of carbohydrates and their derivatives.

Preparation and properties of new surfactants containingd-glucosamine as the building block

Three types of new surfactants were prepared by usingN-acetyl-d-glucosamine as a starting material. The first type of surfactant, sodium methyl 4,6-O-alkylidene-2-(carboxyl-atomethylamino)-2-deoxy-d-glucopyranoside, was prepared successively by the following treatments: methyl glucosidation ofN-acetyl-d-glucosamine, transacetalization with an appropriate aldehyde dimethyl acetal, deacetylation, and finally reaction of the resulting methyl-4,6-O-alkylidene-2-amino-2-deoxy-d-glucopyranoside (2-amino precursor) with bromoacetic acid. The reaction of this 2-amino precursor with methyl iodide yielded the second type of surfactant, methyl 4,6-O-alkylidene-2-deoxy-2-(trimethylammonio)-d-glucopyranoside iodide, in excellent yield. The last type of compound, sodium methyl 2-acetamide-4,6-O-alkylidene-3-O-[1-(carboxylato)-ethyl]-2-deoxy-d-glucopyranoside, was synthesized by the reaction of methyl 2-acetamide-4,6-O-alkylidene-2-deoxy-d-glucopyranoside with 2-chloropropionic acid. Concerning the two carboxylate types of surfactants, the compounds containing a C9 or C11 hydrophobic chain in the alkylidene part showed higher water solubility than the corresponding compounds containing a C7 hydrophobic chain. Both the micelle-forming property and the ability to lower the surface tension of these carboxylate types of compounds increased with an increase in the length of the hydrophobic chain in the alkylidene part. These compounds can be applied to new acid-decomposable types of cleavable surfactants because they contain an acetal group. The acetal bond of the ammonium type of compound was cleaved more slowly than that of the corresponding carboxylate types of surfactants in 2% aqueous HCI solution. The biodegradabilities of these compounds were also determined.

Chiral discrimination of permethylated gluco-oligosaccharide toward amino acid ester salts

The chiral discrimination ability of permethylated glucopyrano-oligosaccharides toward amino acid 2-propyl ester hydrochlorides was evaluated using FAB mass spectrometry. In the given permethylated homo-oligosaccharides, permethylated β-cello-oligosaccharide series (II) showed remarkably higher S-selectivity toward tryptophan ester salts (Trp-O-iPr+) independent of the numbers (n) of the glucopyranose unit (n=2–5). The hexamer and heptamer of the permethylated β-malto-oligosaccharide series (I) showed the very similar enantioselectivity to permethylated α- and β-cyclodextrin.

Measurement of chiral amino acid discrimination by cyclic oligosaccharides: a direct FAB mass spectrometric approach

The novel cyclic oligosaccharides, permethylated cyclofructans MECF, 1b and 2b, discriminate enantiomers of chiral amino acid ester hydrochlorides.

Regioselective epoxidation of geraniol with m-chloroperbenzoic acid in emulsion systems

Abstract Oxidation of geraniol with m-chloroperbenzoic acid (m-CPBA) in emulsion systems gave 2,3-epoxygeraniol selectively in high yield.