Synthesis of Ether-Linked Di- and Trisaccharide Derivatives Part II- Functionalization and Potential Applications of Ether-Linked Di- and Trisaccharides Containing d-Glucose

Abstract

We have prepared three series of functionalized disaccharides of the type A(6→n)B and a trisaccharide with the formula A-O-B-O-C, in which A = D-glucose (or its derivatives) and both B and C are any of D-fructose, D-galactose, D-glucose, xylitol and glycerol (or their derivatives). These compounds resulted from the regiospecific functionalization of either A or B and either the partial or total deprotection of either 6-O-(3-deoxy-1,2:5,6-di-O-isopropylidene-α-D-glucofuranos-3-yl)-3-O-alkyl-1,2-O-isopropylidene-α-D-glucofuranose or its analogues of type 1 described in part I.¹ We also report results on surface activity and biological properties of some of the molecules prepared.     

Synthesis of Tetrasaccharide Repeating Unit of the K-Antigen from Klebsiella Type-16

Abstract

Starting from L-fucose, D-glucose and lactose, methyl O-[2,3-di-O-benzoyl-4, 6-O-(4-methoxybenzylidene)-β-D-glucopyranosyl]-(1→4)-2,3-di-O-benzoyl-α-L-fucopyranoside and methyl O-(2,3,4,6-tetra-O-benzyl-β-D-galactopyranosyl)-(1→4)-O-(2,3,6-tri-O-benzyl-α-D-glucopyranosyl)-(1→4)-O-(methyl 2,3-di-O-benzoyl-β-D-glucopyranosyluronate)-(1→4)-2,3-di-O-benzoyl-α-L-fucopyranoside were synthesized. Removal of protecting groups gave the tetrasaccharide repeating unit of the antigen from Klebsiella type-16 in the form of its methyl ester methyl glycoside.     

Synthesis of optically inactive cellulose via cationic ring-opening polymerization

Cellulose, which comprises D-glucose and L-glucose (D,L-cellulose), was synthesized from D-glucose (1D) and L-glucose (1L) via cationic ring-opening polymerization. Specifically, the ring-opening copolymerization of 3-O-benzyl-2,6-di-O-pivaloyl-β-D-glucopyranoside (2D) and 3-O-benzyl-2,6-di-O-pivaloyl-β-D-glucopyranoside (2L), synthesized from compounds 1D and 1L, respectively, in a 1:1 ratio, afforded 3-O-benzyl-2,6-di-O-β-D,L-glucopyranan (3DL) with a degree of polymerization (DPn) of 28.5 (Mw/Mn?=?1.90) in quantitative yield. The deprotection of compound 3DL and subsequent acetylation proceeded smoothly to afford acetylated compound 4DL with a DPn of 18.6 (Mw/Mn?=?2.08). The specific rotation of acetylated compound 4DL was?+?0.01°, suggesting that acetylated compound 4DL was optically inactive cellulose triacetate. Furthermore, before acetylation, compound 4DL was an optically inactive cellulose comprising an almost racemic mixture of D-glucose and L-glucose. Compound 4DL was an amorphous polymer. This is the first reported synthesis of optically inactive D,L-cellulose.

     

Synthesis of New Spirodifuranose Derivatives by Reduction of Stable Spiro-Endoperoxides

Synthesis of three new stable spirodifuranose derivatives (3, 5, and 7), which cannot be obtained easily using ordinary synthetic methods, has been achieved by reduction of 3-O-acetyl and 3-O-methyl derivatives of (4R)-1,2-O-alkylidene-5-eno-4,7-epidioxy-5,6,8-trideoxy-α-D-threo-1,4-furano-4,7-diulo-octoses (1, 4, and 6).     

Synthesis of Ether Linked Pseudo-Oligosaccharides Via 5,6-Cyclic Sulfate Derivatives of Protected Manno and Glucofuranose

Abstract

C-6 ring opening of 5,6-cyclic sulfate derivatives of protected manno and glucofuranose with carbohydrate alkoxides gave ether linked pseudo-di or trisaccharides. Use of methyl 2,3-O-isopropylidene-5,6-O-sulfuryl-α-D-mannofuranoside 1 led to protected pseudo-disaccharide D-Glcf-(3→6)-D-Manf-(5→6)-D-Manf 4 and protected pseudo-trisaccharide D-Manf-(6→3)-D-Glcf-(6→3)-D-Glcf 11 derivatives in 66% and 41% overall yields, respectively.     

Synthesis of 2,6-Dideoxy-6-Thio Derivatives of KDO

ABSTRACT

Ammonium 2,3,6-trideoxy-2,6-epithio-D-manno-2-octenoate (8), ammonium 2,3,6-trideoxy-2,6-epithio-D-glycero-D-talo-octanoate (10a), ammonium 2,3,6-trideoxy-2,6-epithio-D-glycero-D-galacto-octanoate (10b) and ammonium 2,3,6-trideoxy-2,6-epithio-oxa-D-glycero-D-galacto-octanoate (13) have been synthesised as potential inhibitors of the enzyme CMP-KDO synthetase. The key step in the synthesis of 8 was the elimination of water from methyl 3,6-dideoxy-4,5:7,8-di-O-isopropylidene-6-thio-D-manno-2-octulosonate (4) using chlorodiphenylphosphine, imidazole and bromine to give the unsaturated methyl 2,3,6-trideoxy-2,6-epithio-4,5:7,8-di-O-isopropylidene-D-manno-2-octenoate (5). For the synthesis of 10a and 10b, zinc reduction of methyl 3,6-dideoxy-4,5:7,8-di-O-isopropylidene-6-S-(4-methoxybenzyl)-6-thio-2-O-(trichloro-tert-butoxycarbonyl)-D-manno-2-octenoate (2) gave an epimeric mixture of an α-hydroxyester 6 which was ring closed by in situ activation of the hydroxyl group using triphenylphosphine and tri-iodoimidazole followed by cleavage of the p-methoxybenzyl group to give 7a and 7b, which then were deprotected to give 10a and 10b.     

NMR and X-Ray Diffraction Study of Some Inositol Derivatives 1

Abstract

We have determined the preferred conformers in solution by a detailed NMR analysis using COSY and HETCOR experiments of three inositol isomers: myo (1), scyllo (2) and epi (3) plus sixteen derivatives of myo-inositol: 1,2,3,4,5,6-hexa-O-acetyl-myo-inositol (4), 1,2,-O-isopropylidene-myo-inositol (5), 1,2:4,5-di-O-isopropylidene-myo-inositol (6), 3,4,5,6-tetra-O-acetyl-1,2-O-isopropylidene-myo-inositol (7), 3,4,5,6-tetra-O-acetyl-myo-inositol (8), 1,2-O-isopropylidene-3,6-di-O-tosyl-myo-inositol (9), 1,2-O-isopropylidene-3,4,6-tri-O-tosyl-myo-inositol (10), 1,2:4,5-di-O-isopropylidene-3-O-tosyl-myo-inositol (11), 3,6-di-O-benzyl, 1,2:4,5-di-O-isopropylidene-myo-inositol (12), 3,6-di-O-benzyl-1,2-O-isopropylidene-myo-inositol (13), 3,6-di-O-benzyl-myo-inositol (14), 1,2-O-cyclohexylidene-myo-inositol (15), 1,2:4,5-di-O-cyclohexylidene-myo-inositol (16), 1,2:5,6-di-O-cyclohexylidene-myo-inositol (17), 1,3,5-O-(orthoformate)-myo-inositol (18) and 2-benzyl-1,3,5-O-(orthoformate)-myo-inositol (19). The X-ray diffraction structure of compounds 2, 6-8, 18 and 19 are reported.

     

嘧啶并呋咱核苷衍生物的制备及其活性初探

4H,6H-[1,2,5]噁二唑并[3,4-d]嘧啶-5,7-二酮1-氧化物(1)和6-甲基-4H,6H-[1,2,5]噁二唑并[3,4-d]嘧啶-5,7-二酮1-氧化物(2)是一氧化氮(NO)供体, 将它们分别在无溶剂条件下与高温熔融的全乙酰基保护的核糖、木糖、葡萄糖进行糖基化反应, 分别得到相应的噁二唑并[3, 4-d]嘧啶核苷类化合物7, 9～12, 化合物7经NH₃-MeOH处理, 去O-乙酰基制得8, 这些新型核苷化合物可作为潜在的NO供体. 部分此类化合物的生物活性研究表明, 嘧啶并呋咱核苷衍生物具有抗病毒、抗肿瘤活性, 为研究抗病毒、抗肿瘤药物提供了新结构类型的候选化合物.     

Talopyranose Derivatives Suitable for the Planned Synthesis of Teichoic Acids Containing Di-Glycosylated Ribitol Units

ABSTRACT

Easily accessible 1,6-anhydro-2,3-O-(S)-benzylidene-β-D-mannopyranose was converted in four steps to 1,6-anhydro-3,4-di-O-benzyl-β-D-talopyranose. Glycosylation of the latter with ethyl 2,3,4-tri-O-acetyl-1-thio-α-L-rhamnopyranoside gave, after further processing, 1-O-allyl-3,4-di-O-benzyl-2-O-(2,3,4-tri-O-benzyl-α-L-rhamnopyranosyl)-L-ribitol.     

Mimics of the Structural Elements of Type III Group B Streptococcus Capsular Polysaccharide. Part I: Synthesis of a Carboxylate-Containing Pentasaccharide

Abstract

A carboxylate-containing pentasaccharide, methyl O-(β-d-galactopyranosyl)-(1→4)-O-(β-d-glucopyranosyl)-(1→6)-O-{3-O-[(S)-1-carboxyethyl]-β-d-galactopyranosyl-(1→4)-O}-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-(1→3)-β-d-galactopyranoside (27) was synthesized by block condensation of suitably protected donors and acceptors. Phenyl 3-O-benzyl-4,6-di-O-chloroacetyl-2-deoxy-2-phthalimido-1-thio-β-d-glucopyranoside (17) was condensed with methyl 2,4,6-tri-O-benzyl-β-d-galactopyranoside (4) to afford a disaccharide, methyl O-(3-O-benzyl-4,6-di-O-chloroacetyl-2-deoxy-2-phthalimido-β-d-glucopyranosyl)-(1→3)-2,4,6-tri-O-benzyl-β-d-galactopyranoside (18). Removal of chloroacetyl groups gave 4,6-diol, methyl 0-(3-O-benzyl-2-deoxy-2-phthalimido-β-d-glucopyranosyl)-(1→3)-2,4,6-tri-O-benzyl-β-d-galactopyranoside (19), in which the primary hydroxy group (6-OH) was then selectively chloroacetylated to give methyl O-(3-O-benzyl-6-O-chloroacetyl-2-deoxy-2-phthalimido-β-d-glucopyranosyl)-(1→3)-2,4,6-tri-O-benzyl-β-d-galactopyranoside (20). This acceptor was then coupled with 2,4,6-tri-O-acetyl-3-O-[(S)-1-(methoxycarbonyl)ethyl]-α-d-galactopyranosyl trichloroacetimidate (14) to afford a trisaccharide, methyl O-{2,4,6-tri-O-acetyl-3-O-[(S)-l-(methoxycarbonyl)ethyl]-β-d-galactopyranosyl}-(1→4)-O-(3-O-benzyl-6-O-chloroacetyl-2-deoxy-2-phthalimido-β-d-glucopyranosyl)-(1→3)-2,4,6-tri-O-benzyl-β-d-galactopyranoside (21). Removal of the 6-O-chloroacetyl group in 21 gave 22, which was coupled with 4-O-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl)-2,3,6-tri-O-acetyl-α-d-glucopyranosyl trichloroacetimidate (23) to yield protected pentasaccharide 24. Standard procedures were used to remove acetyl groups and the phthalimido group, followed by N-acetylation, and debenzylation to yield pentasaccharide 27 and a hydrazide by-product (28) in a 5:1 ratio, respectively. Compound 27 contains a complete repeating unit of the capsular polysaccharide of type III group B Streptococcus in which terminal sialic acid is replaced by an (S)-1-carboxyethyl group.     

Synthesis of 1-O-(Methylthio)thiocarbonyl Sugar Derivatives Bearing Acyl Protective Groups Using Phase Transfer Catalysis Methods

Abstract

2,3,4,6-Tetra-O-acetyl-D-glucopyranose (1) was successfully transformed to an anomeric mixture of 2,3,4,6-tetra-O-acetyl-1-O-(methylthio)thiocarbonyl-D-glucopyranose (2) by liquid - liquid and solid - liquid phase transfer methods. Similar anomeric free sugar derivatives bearing acetyl or benzoyl protective groups were also smoothly converted to the corresponding 1-O-(methylthio)thiocarbonyl derivatives. Thermal rearrangement of 1-O-(methylthio)thiocarbonylfuranose derivatives proceeded well to give 1-S-methylthiocarbonyl-1-thiofuranose derivatives.     

The Synthesis of Four Dideoxygenated Analogues of β-Maltosyl-(1→4)-Trehalose

Abstract

Four derivatives of β-maltosyl-(1→4)-trehalose were prepared, each with two deoxy functions in one of the constitutive disaccharide building blocks. 2,3-Di-O-acetyl-4,6-dideoxy-4,6-diiodo-α-D-galactopyranosyl- (1→4) ?1,2,3,6-tetra-O-acetyl-D-glucopyranose (3) was employed as a precursor for the 4?,6?-dideoxygenated tetrasaccharide 9: coupling of 3 with 2,3,6-tri-O-benzyl-α-D-glucopyranosyl 2,3,6-tri-O-benzylidene-α-D-glucopyranoside (4) furnished the tetrasaccharide 5 which was deiodinated and deprotected to yield the target tetrasaccharide 9. Secondly, the dideoxygenated maltose derivative 3-deoxy-4,6-O-isopropylidene-2-O-pivaloyl-β-D-glucopyranosyl- (1→4) ?1,6-anhydro-3-deoxy-2-O-pivaloyl-β-D-glucopyranose (10) was ring-opened to the anomeric acetate 11. A [2+2] block synthesis with 4 in TMS triflate mediated glycosylation gave a tetrasaccharide which was deprotected to the 3″,3?-dideoxygenated analogue of β-maltosyl-(1→4)-trehalose. For the third tetrasaccharide, 2,3,2″,3′-tetra-O-benzyl-α,α-trehalose was iodinated at the primary positions and deiodinated in the presence of palladium-on-carbon, then this acceptor was selectively glycosylated with hepta-O-acetyl-maltosyl bromide (20). Removal of protective groups furnished the maltosyl trehalose tetrasaccharide deoxygenated at positions C-6 and C-6′. to prepare a 3,3′-dideoxygenated trehalose, the free hydroxyl groups of 2-O-benzyl-4,6-O-(R)-benzylidene-α-D-glucopyranosyl 2-O-benzyl-4,6-O-(R)-benzylidene-α-D-glucopyranoside (25) were reduced by Barton-McCombie deoxygenation. One of the benzylidene groups was opened reductively with sodium cyanoborohydride. The resulting free hydroxyl group at the 4′-position was glycosylated in a Koenigs-Knorr reaction with 20 to yield the 3,3′-dideoxygenated tetrasaccharide 32, the fourth target oligosaccharide, after deprotection.     

Chemical-Enzymatic Synthesis of A Branched Hexasaccharide Fragment of Type Ia Group B Streptococcus Capsular Polysaccharide

ABSTRACT

A branched hexasaccharide fragment of type Ia group B streptococcal polysaccharide, α-NeuAc(2→3)-β-D-Gal(1→4)-β-D-GlcNAc(1→3)-[β-D-Glc(1→4)]-β-D-Gal(1→4)-β-D-Glc-OMe (13), has been synthesized by chemical-enzymatic procedures. Chemical synthesis of a pentasaccharide, β-D-Gal(1→4)-β-D-GlcNAc(1→3)-[β-D-Glc(1→4)]-β-D-Gal(1→4)-β-D-Glc-OMe (12), was achieved from glycosyl donor, 4-O-(2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl)-3,6-di-O-acetyl-2-deoxy-2-phthalimido-β-D-glucopyranosyl trichloroacetimidate (9), and acceptor, methyl O-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-(1→4)-O-(2,6-di-O-benzyl-β-D-galactopyranosyl)-(1→4)-2,3,6-tri-O-benzyl-β-D-glucopyranoside (6), by block condensation in 41% yield. Following enzymatic sialylation of 12 at the 3-O-position of its terminal galactopyranosyl residue using recombinant α-(2→3)-sialyltransferase and CMP-NeuAc afforded 13 in 59% yield.     

Synthesis of 3-Aryl-5-C-Glycosylisoxazoles from Several Aldehydo-Sugar Derivatives

ABSTRACT

The synthesis of several 3-aryl-5-glycosylisoxazole derivatives has been achieved. By condensation of the protected aldehydo-sugars 2,3-O-isopropylidene-D-glyceraldehyde (1), 2,3:4,5-di-O-isopropylidene-aldehydo-D-arabinose (2) and D-xylose (3), and 2,5-anhydro-3,4,5-tri-O-benzoyl-D-mannose (4) with benzoylmethylenetriphenylphosphorane, enulose derivatives were formed, which were later converted into a,ß-unsaturated ketoximes. These ketoximes were oxidatively cyclized with iodine and, after removal of the hydroxyl protecting groups, 3-phenyl-5-glycosylisoxazoles were formed.     

Stereochemie der Enzymatischen Hydrolyse von Saccharose und Raffinose Durch Invertase

Abstract

Reaction of 2-O-unprotected 1-O-silyl-protected D-glucose and D-galactose derivatives 5a-d with benzyl bromide in the presence of sodium hydride as the base afforded 1-O-benzyl 2-O-silyl derivatives 6aα/β - 6dα/β. Thus, prior to anomeric O-benzylation, trans-1,2-silyl group migration takes place. Ensuing removal of the 2-O-silyl group furnishes 2-O-unprotected compounds 8aα/β - 8dα/β, which are useful building blocks. More prone to 1-O-silyl group migration is mannose as shown for derivatives of 4,6-O-benzylidene-D-mannose 9. Cis-1,2- and cis-2,3-silyl group migrations affording compounds 15 and 13 were already observed on deacetylation of the thexyldimethylsilyl 2,3-di-O-acetyl derivative 12β under Zemplén conditions.     

Synthetic Studies on Sialoglycoconjugates. 4: Synthesis of 5-Acetamido-3,5-Dideoxy-d-Galacto-2-Octulosonic Acid Derivatives and Analogs

Abstract

5-Acetamido-3.5-dideoxy-D-galacto-2-octulosonic acid derivatives and the α-2-thioanalog (14) were synthesized. Methyl [2-(trimethylsilyl)ethyl 5-acetamido-3,5-dideoxy-α-D-galacto-2-octulopyranosid]onate (8), prepared from methyl [2-(trimethylsilyl)ethyl 5-acetamido-3,5-dideoxy-D-glycero-α-D-galacto-2-nonulopyranosid]onate (1) via 8,9-O-isopropylidenation, O-acetylation, O-deisopropylidenation, metaperiodate oxidation, and sodium borohydride reduction, was converted, by selective bromination, into the 8-bromo derivatives (9). Compound 12, derived from 8 via O-acetylation and boron trifluoride etherate treatment, was converted to the 2-chloro derivative (13), which underwent displacement with potassium thioacetate, to yield methyl 5-acetamido-4,7,8-tri-O-acetyl-2-S-acetyl-2-thio-α-D-galacto-2-octulopyranosonate (14).     

氨基糖衍生物二丁基锡配合物的合成、结构表征和生物活性

分别由2-[(2Z)-3-羧基-1-氧代-2-丙烯基]氨基-2-脱氧-1,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖(1a), 2-[(2-羧基苯甲酰基)氨基]-2-脱氧-1,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖(2a)和氧化二正丁基锡反应合成了两个新化合物双-{2-[(2Z)-3-羧基-1-氧代-2-丙烯基]氨基-2-脱氧-1,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖}-二正丁基锡酯(1)和双-{2-[(2-羧基苯甲酰基)氨基]-2-脱氧-1,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖}-二正丁基锡酯(2), 并经红外光谱、核磁共振(¹H, ¹³C NMR)、质谱初步确定了其结构. 体外抗肿瘤活性结果表明, 化合物1对人肺癌细胞株A-549和人肝癌细胞株BEL-7402的细胞毒活性显示为强效; 而对小鼠白血病细胞株P388和人白血病细胞株HL-60的细胞毒活性为弱效. 化合物2对肿瘤细胞株HL-60, A-549和BEL-7402具有强效的细胞毒活性; 而对肿瘤细胞株P388的作用则为弱效. 克隆基因分析表明化合物1和2在3.82×10^－6 和 3.02×10^－6 mol/L均具有造血细胞毒性.     

Synthesis of 2′-Iodo Analogues of β-Rhodomycins1

Abstract

10-O-(R/S)Tetrahydropyranosyl-β-rhodomycinone (5a,b) was prepared via 7,9-O-phenylboronyl-β-rhodomycinone (3) from β-rhodomycinone (1). Glycosidation of 5a,b with 3,4-di-O-acetyl-1,5-anhydro-2,6-dideoxy-L-arabino-hex-1-enitol (3,4-di-O-acetyl-L-rhamnal) (6) and 3,4-di-O-acetyl-1,5-anhydro-2,6-dideoxy-L-lyxo-hex-1-enitol (3,4-di-O-acetyl-L-fucal) (7) using N-iodosuccinimide gave the corresponding 7-O-glycosyl-β-rhodomycinones 8a,b, 9a,b and 10a,b, 11a,b. After cleavage of the THP-ether and O-deacetylation 7-O-(2,6-dideoxy-2-iodo-α-L-manno-hexopyranosyl)-β-rhodomycinone (14) and 7-O-(2,6-dideoxy-2-iodo-α-L-talo-hexopyranosyl)-β-rhodomycinone (16) were obtained.     

Synthesis and Pharmacological Activity of Annelated Pyrimidine Derivatives

A series of 2,3-diglycosylpyrimidine 4, annelated pyrimidine derivatives, pyrazolo-[3,4-d]pyrimidine 8, ditetrazolo[1,5-a; 1′5′]pyrimidine 9, 2,9a,10-triazaanthracene 12, thieno- [2,3-d]pyrimidine 14, 9-thia-1,3,5,7-tetraazafluorene-8-one 15, 7-oxa-9-thia-1,3,5-triazafluorene-8-one 16, and 5-oxa-9-thia-1,3-diazafluorene 21a , b derivatives have been synthesized via a sequence of heterocyclization reactions of suitably functionalized 6-[5-(4-bromophenyl)oxazol-4-yl]-1,2,3,4-tetrahydro-2-thioxo-4-oxopyrimidine-5-carbonitrile (2) with different electrophiles and nucleophiles. The new compounds were prepared with the objective to study their pharmacological properties.     

Expeditious Synthesis of a Trisubstrate Analogue for α(1→3)Fucosyltransferase

Abstract

The synthesis of cyclohexyl 2-acetamido-2-deoxy-3-O-{2-O-[2-(guanosine 5′-O-phosphate)ethyl]-α-L-fucopyranosyl}-β-D-glucopyranoside (1), a potential inhibitor of α(1→3)fucosyltransferases, is described. Target compound 1 was assembled via fucosylation of cyclohexyl 2-acetamido-2-deoxy-4,6-O-isopropylidene-β-D-glucopyranoside (6) with ethyl 2-O-[2-(benzoylhydroxy)ethyl]-3,4-O-isopropylidene-1-thio-β-L-fucopyranoside (5) followed by debenzoylation, subsequent condensation of the resulting compound with 3′,4′ -di-O-benzoyl-5′ -O-(2-cyanoethyl-N,N-diisopropylphosphoramidite)-2-N-diphenylacetylguanosine (10) and deprotection.