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Funoran extracted from the red seaweed Gloiopeltis furcata Post. et Ruprecht was fractionated into four polysaccharide fractions in terms of differences in solubility of their cetylpyridinium salt in potassium chloride solution. Besides the main fraction constructed by an agarose sulphate structure with negative optical rotation, minor polysaccharide fractions with positive optical rotation were obtained. One of the minor polysaccharide fractions contained d - and l -galactose (Gal), 6-O-methyl- d -Gal, 3,6-anhydro- l -Gal and sulphate. Partial hydrolysis and partial methanolysis studies of this fraction led to identification of oligosaccharides attributable to both agaroid and carrageenan backbones, i.e. [ → 3) d -Gal(1 → 4) l -Gal(1 → ][→ 3) d -Gal(1 → 4)3,6-and [ → 3)6- O -methyl- d -Gal(1 → 4)D-Gal(l → ]. Methylation analysis and alkaline treatment study of this fraction revealed that the sulphate groups were located at O-6 of all the (1 → 4)-linked l - and a part of the (1 → 4)-linked d -Gal residues, O-6 of a part of the (1 → 3)-linked d -Gal residue, and both O-2 and O-4 of the (1 → 3)-linked 6-O-methyl- d -Gal residue and the other (1 → 3)-linked d -Gal residue.

Starch, agarose, κ-carrageenan and porphyran were sulfated by sulfuric acid with dicyclohexylcarbodiimide as a condensation reagent. In all the cases, the sulfation at O-6 appeared to be predominant on the basis of results from methylation analyses. Although the reactivities of the other hydroxyl groups towards the present sulfation reaction were less than that at C-6, they varied depending on the position in the sugar residue of the polysaccharides. The sulfated agarose was further fractionated in terms of the difference in the solubility of its cetylpyridinium salt to KCl solution. The major fraction resembled the main polysaccharide of funoran (agarose 6-sulfate) on the basis of the behavior of its cetylpyridinium salt, 13C NMR measurements and methylation analyses.

ISP-I (myriocin, thermozymocidin) was structurally simplified to give 2-amino-2-alkyl-1,3-propanediols that were also potent immunosuppressants. Among the series, 2-amino-2-pentadecyl-1,3-propanediol most actively prolonged rat skin allograft survival and was more effective than ciclosporin.

Funoran extracted from the red seaweed, Gloiopeltis complanata, was fractionated based on the solubility of its cetylpyridinium salt in KCl solution to give the fractions PSl and PS2. PS2 was further fractionated into PS2G that formed a gel in 0.5 n KCl, and PS2S that did not form a gel in saturated KCl. PSl, PS2G and PS2S were different in composition and properties showing that the funoran was heterogeneous. On the basis of the results from composition analyses, partial methanolysis studies, methylation studies, 13C-NMR spectrum measurements, and regioselective desulphation studies employing a silylating reagent, N,O-bis(trimethylsilyl)acetamide, PS2G was shown to consist chiefly of 6-O-sulphated agarose, repeats of →3)6-SO3-β- d -Gal(1→4)3,6-anhydro-α- l -Gal(1→; and PS2S to contain repeats of →3)6-SO3-β- d -Gal(1→4)6-SO3-α- l -Gal(1→ as well as smaller amounts of →3)2,6-di-SO3-β- d -Gal(1→ and →3)2-SO3-β- d -Gal(1→ residues.

Methyl alpha- and beta-D-galactopyranosides and 4-O-beta-D-galactopyranosyl-3,6-anhydro-L-galactose dimethylacetal were sulfated with sulfuric acid and dicyclohexylcarbodiimide as a condensation reagent. The sulfated sugars were isolated by ion-exchange chromatography, characterized, and assigned by methylation analyses. On the basis of the yield of each sulfated product that was isolated, sulfation on O-6 appeared to be predominant.

Several immunosuppressants, ISP-I [(2S,3R,4R)-(E)-2-amino-3,4-dihydroxy-2-(hydroxymethyl)-14-oxoeicos++ +-6-enoic acid, myriocin = thermozymocidin] and mycestericins A-G, were isolated from culture broths of Isaria sinclairii and Mycelia sterilia, respectively. In order to investigate structure-activity relationships, extensive modifications of ISP-I were conducted, and it was established that the fundamental structure possessing the immunosuppressive activity is a symmetrical 2-alkyl-2-aminopropane-1,3-diol. The tetradecyl, pentadecyl, and hexadecyl derivatives prolonged rat skin allograft survival in the combination of LEW donor and F344 recipient and were more effective than cyclosporin A. Among them, 2-amino-2-tetradecylpropane-1,3-diol hydrochloride, ISP-I-55, showed the lowest toxicity. ISP-I-55 is a promising lead compound for the development of effective immunosuppressants for organ transplantations and for the treatment of autoimmune diseases.

Two polysaccharide fractions, PS1 and PS2 from Lomentaria catenata consisted of D-Gal, L-Gal, D-Glc, D-Xyl, D-GlcA and sulphate. Partial hydrolysis led to the isolation and identification of oligosaccharides indicating the co-existence of an agarose and carrageenan backbone structure, in which D-Glc and D-GlcA residues occur as single units branching at O-3 of --4)alpha-D-Gal(1--and O-4 of --3)beta-D-Gal(1--, respectively.

Photolyses of α-bromoanthraquinones (1-bromo-, 1,5-dibromo-, and 1,8-dibromoanthraquinones) with 366-nm light in ethanol at room temperature gave rise to the formation of debrominated 9,10-anthracenediol as a final product. This was interpreted in terms of the sequence of the formation of α-bromo-9,10-anthracenediols followed by the photochemical dehydrobromination yielding the corresponding anthraquinones with one less bromine atom than original ones. Photolysis of 2-bromoanthraquinone gave rise to the formation of 2-bromo-9,10-anthracenediol, and no dehydrobromination was observed. Combined with the values of the quantum yields of photoreduction, the results of the laser photolyses revealed that the rate constant for the hydrogen-atom abstraction from ethanol decreased as an increase of the ππ* character of the lowest triplet states of α-bromoanthraquinones.

Phosphorescence spectra and triplet lifetimes of anthraquinone and α-halogenoanthraquinones were studied in EPA at 77 K. It is suggested that the emitting states of α-halogenoanthraquinones are the lowest triplet states and that halogen substitution at the α position(s) in anthraquinone affects the electronic configuration of the lowest triplet states and their lifetimes.

In the 366 nm photolyses of α-chloroanthraquinones (the 1-chloro, 1,5-dichloro and 1,8-dichloro compounds) the absorption bands of the reactants and the products shifted to the blue and anthrahydroquinone was produced as the final product. Combined with the results of the 313 nm photolyses of α-chloroanthraquinones and those of the 450 nm or 465 nm photolyses of α-chloroanthrahydroquinones, the results of the 366 nm photolyses of α-chloroanthraquinones were interpreted in terms of the following consecutive reactions: 1,5-dichloroanthraquinone or 1,8-dichloroanthraquinone 1,5-dichloroanthrahydroquinone or 1,8-dichloroanthrahydroquinone 1-chloroanthraquinone 1-chloroanthrahydroquinone anthraquinone anthrahydroquinone. In the step involving the photoreduction of 1,8-dichloroanthraquinone, however, a novel phenomenon was observed: the photolysis gave rise to the formation of a precursor which disappeared by a dark reaction, following a first-order rate law, to yield both the reactant and the product (1,8-dichloroanthrahydroquinone) simultaneously. This precursor was assigned to a complex of two 1,8-dichloroanthrasemiquinone radicals. The photolysis of 2-chloroanthraquinone gave rise to the formation of 2-chloroanthrahydroquinone, and no dehydrochlorination was observed.

1. The mucilage of Chondrus ocellatus Holmes has been investigated by the partial methanolysis method. 2. A new disaccharide, the structure of which is shown to be 4-O-β-D-galactopyranosyl-3,6-anhydro-D-galactose, has been isolated in the form of its dimethylacetal and methyl β-glycoside in a good yield. 3. The disaccharide has been named carrabiose. 4. It has been suggested that 1→3′ linked carrabiose represents the repeating unit for the most part of the carbohydrate of the Chondrus mucilage.

1. Partial methanolysis of agar has led to isolation of a crystalline double barium salt, which is separable into its components, barium methylsulfate and a barium salt of an organic acid. 2. From the last salt above mentioned, there has been obtained a free acid having the formula C14H21O9(OCH3)2COOH as its crystalline monohydrates. Its methyl ester and amide have also been prepared in a crystalline condition. 3. The acid obtained, a new compound, has been proved to be a disaccharide derivative composed of 3,6-anhydro-L-galactose, D-galactose and pyruvic acid. 4. It has also been proved that the pyruvic acid residue is linked through its carbonyl group with the D-galactose residue. 5. The isolation of the pyruvic acidlinking disaccharide derivative substantiates the view that pyruvic acid is an intrinsic constituent of agar.

Commercial agar was subjected to complete hydrolysis with dilute sulfuric acid, and the products were carefully investigated. Besides D- and L-galactose, which have been known to exist, there were isolated small amounts of D-xylose, 6-O-methyl-D-galactose, 4-O-methyl-L-galactose, and O-methylpentose, all the sugars except the last one being obtained in crystalline forms. Among these products, 4-O-methyl-L-galactose is a new compound, so its structure has been fully investigated. As commercial agar is made from Gelidium amansii, occasionally mixed with several other species of seaweeds, the experiments were repeated for the agar prepared from G. amansii only. The same products as those from commercial agar were isolated except the O-methylpentose.

The extraction of Grateloupia elliptica with hot water afforded a mucilageous sulfated polysaccharide, which was then purified through precipitation as a complex with cetyl pyridinium chloride. In order to examine the component sugars, the polysaccharide was subjected to complete hydrolysis and methanolysis, the respective products of which were then carefully fractionated both by crystallization and chromatography in order to isolate the individual products. The results obtained, coupled with the data of quantitative estimation, have shown that the bulk of the polysaccharide is composed of D-galactose, L-galactose, 3, 6-anhydro-D-galactose, and sulfate, existing in the approximate molar proportion of 9 : 1 : 2 : 8. In addition to these main components, the presence of small amounts of D-xylose, 2-O-methyl-L-galactose, 4-O-methyl-D-galactose and 2-O-methyl-3, 6-anhydro-L-galactose has also been established. These compounds have been identified on the crystalline basis. The partially-methylated sugars isol...

Location of the sulfate groups in κ carrageenan from G. tenella has been re-investigated by adapting the method, which was devised by Bouveng for locating the acetyl groups in hemicellulose. In this method, the sulfate groups were replaced by methyl groups through a series of reactions consisting of blocking the free hydroxyl groups with phenylcarbamoyl groups, removing the sulfate groups and methylating the newly formed hydroxyl groups. The blocking substituents were then removed, and the positions of the methoxyl groups were investigated by the standard method. The results have shown, in accordance with the conclusion based on the methylation data, that one forth of the 1,4-linked 3,6-anhydro-D-galactose residues are 2-sulfated and that the 1,3-linked D-galactose residues are 4-sulfated. No evidence was obtained to indicate the presence of D-galactose 2,6-disulfate, which had been presumed by other workers. The problem concerning the acyl migration of the blocking groups during the process has also been...

An alkaline treatment of κ-carrageenan from Gigartina tenella resulted in the change of the proportions of galactose, 3,6-anhydro-galactose and sulfate from 100 : 91 : 124 to 95 : 96 : 119. Fragmentation of the methylated polysaccharide gave 2,4,6-tri-O-, 2,6-di-O-, and mono-O-methyl-D-galactose in the molar proportions of 1 : 18 : 0.8 together with 3,6-anhydro-D-galactose and its 2-O-methyl-derivative in the molar proportion of 1 : 4. From these and other data, it is concluded that the polysaccharide is composed of the residues of 1,3-linked β-D-galactose 4-sulfate (95 mol), 1,4-linked α-D-galactose 6-sulfate (5 mol), and 1,4-linked 3,6-anhydro-α-D-galactose (67 mol) and its 2-sulfate (24 mol), and that the 1,3- and 1,4-linked residues are repeated alternatingly to form a chain macro-molecule.

1. The mucilage of Gloiopeltis furcata has been subjected to partial methanolysis, which resulted in the isolation of methyl D-galactoside, 3,6-anhydro-L-galactose dimethylacetal, methyl D-xyloside and agarobiose dimethylacetal. 2. Since the agarobiose derivative was obtained in a good yield, it has been concluded that the disaccharide represents the chief repeating unit of the mucilage molecule, if the sulfate residues present in the mucilage are left out of consideration. 3. Xylose has been identified for the first place so far as the Gloiopeltis mucilage is concerned. But the yield was so low that the sugar might be possibly derived from a contaminating xylan.

Carrabiose (3, 6-anhydro-4-O-β-D-galactopyranosyl-D-galactose) was synthesized by a series of reactions involving the condensation of methyl 2-O-p-tosyl-3, 6-anhydro-α-D-galactopyranoside with tetra-O-acetyl-α-D-galactopyranosyl bromide, followed by deacetylation, detosylation, and removal of the glycosidic methoxyl group. From the resulting disaccharide, several crystalline derivatives were prepared. All of these derivatives were identical in every respect with the corresponding compounds, which had been obtained from natural sources.

1. The mucilage of Gloiopeltis furcata has been investigated by the complete methanolysis method. 2. 3,6-Anhydro-L-galactose dimethylacetal and methyl D-galactoside have been isolated from the methanolysate. In addition, L-galactose has also been isolated in the form of the crystalline DL-galactose diethylmercaptal. 3. The yields of the isolates have indicated that the mucilage used contains 3, 6-anhydro-L-galactose, D-galactose and L-galactose in the approximate molar ratio of 8:12:1.

Agarobiose, 3,6-anhydro-4-O-β-D-galactopyranosyl-L-galactose, was synthesized by a series of reactions involving the condensation of 1, 2-O-isopropylidene-3, 6-anhydro-L-galactopyranose with tetra-O-acetyl-α-D-galactosyl bromide, deacetylation with sodium methoxide, and the hydrolytic removal of the O-isopropylidene group. The resulting disaccharide, and its osazone and dimethyl acetal were identical with the corresponding authentic samples obtained naturally.

1. Pyruvic acid has been isolated as its 2,4-dinitrophenylhydrazone from the hydrolysate of agar for the first time. 2. Quantitative determination has indicated that the content of pyruvic acid is 1.06% of agar or one residue for every fifty one hexose residues. 3. It has been suggested that pyruvic acid would be an intrinsic constituent of agar. 4. Several polysaccharides other than agar have been examined, but none of them produced pyruvic acid on hydrolysis.

The polysaccharide extracted from the red seaweed Gigartina tenella has been separated into κ- and λ-polysaccharide by potassium chloride. The former polysaccharide is a gelling component precipitated with potassium chloride, while the latter is a non-gelling component insensitive to the precipitant. Complete hydrolysis and methanolysis, together with quantitative determination, have shown that the κ-polysaccharide is composed mainly of D-galactose, 3, 6-anhydro-D-galactose, and an ester sulfate in the molar proportion 1 : 0.98 : 1.17. Very small amounts of L-galactose and D-xylose have also been isolated from the products of hydrolysis. The partial methanolysis of the κ-polysaccharide yielded dimethyl acetal of carrabiose (4-O-β-D-galactopyranosyl-3, 6-anhydro-D-galactose) in a good yield. It follows from these results that this disaccharide is a chief repeating unit of the carbohydrate moiety of the polysaccharide, as in the case of κ-carrageenan.

3,6-Anhydro-5-O-methyl-D-galactose has been synthesized for the first time through a series of reactions composed of blocking the hydroxyl groups at C2 and C4 of methyl 3,6-anhydro-α-D-galactopyranoside with the phenylcarbamoyl groups, converting the resulting derivative of the methyl glycoside into the corresponding dimethyl acetal, methylating the newly formed hydroxyl group at C5, removing the blocking substituents, and finally hydrolysing the dimethyl acetal. The partially methylated anhydro-sugar obtained was uncrystallizable, and was characterized by its crystalline dimethyl acetal and crystalline aldonamide.