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1.
Intramolecular cyclisation of properly protected and activated derivatives of 2′,3′-secouridine ( = 1-{2-hydroxy-1-[2-hydroxy-1-(hydroxymethyl)ethoxy]-ethyl}uracil; 1 ) provided access to the 2,2′-, 2,3′-, 2,5′-, 2′,5′-, 3′,5′-, and 2′,3′-anhydro-2′,3′-secouridines 5, 16, 17, 26, 28 , and 31 , respectively (Schemes 1–3). Reaction of 2′,5′-anhydro-3′-O-(methylsulfonyl)- ( 25 ) and 2′,3′-anhydro-5′-O-(methylsulfonyl)-2′,3′-secouridine ( 32 ) with CH2CI2 in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene generated the N(3)-methylene-bridged bis-uridine structure 37 and 36 , respectively (Scheme 3). Novel chiral 18-crown-6 ethers 40 and 44 , containing a hydroxymethyl and a uracil-1-yl or adenin-9-yl as the pendant groups in a 1,3-cis relationship, were synthesized from 5′-O-(triphenylmethyl)-2′,3′-secouridine ( 2 ) and 5′-O,N6-bis(triphenylmethyl)-2′,3′-secoadenosine ( 41 ) on reaction with 3,6,9-trioxaundecane-1,11-diyl bis(4-toluenesulfonate) and detritylation of the thus obtained (triphenylmethoxy) methylcompound 39 and 43 , respectively (Scheme 4).  相似文献   

2.
The stereospecific cis-hydroxylation of 1-(2,3-dideoxy-β-D -glyceropent-2-enofuranosyl)thymine (1) into 1-β-D -ribofuranosylthymine (2) by osmium tetroxide is described. Treatment of 2′,3′-O, O-isopropylidene-5-methyl-2,5′-anhydrouridine (8) with hydrogen sulfide or methanolic ammonia afforded 5′-deoxy-2′,3′-O, O-isopropylidene-5′-mercapto-5-methyluridine (9) and 2′,3′-O, O-isopropylidene-5-methyl-isocytidine (10) , respectively. The action of ethanolic potassium hydroxide on 5′-deoxy-5′-iodo-2′,3′-O, O-isopropylidene-5-methyluridine (7) gave rise to the corresponding 1-(5-deoxy-β-D -erythropent-4-enofuranosyl)5-methyluracil (13) and 2-O-ethyl-5-methyluridine (14) . The hydrogenation of 2 and its 2′,3′-O, O-isopropylidene derivative 4 over 5% Rh/Al2O3 as catalyst generated diastereoisomers of the corresponding 5-methyl-5,6-dihydrouridine ( 17 and 18 ).  相似文献   

3.
The regiospecific reaction of 5-vinyl-3′,5′-di-O-acetyl-2′-deoxyuridine ( 2 ) with HOX (X = Cl, Br, I) yielded the corresponding 5-(1-hydroxy-2-haloethyl)-3′,5′-di-O-acetyl-2′-deoxyuridines 3a-c . Alternatively, reaction of 2 with iodine monochloride in aqueous acetonitrile also afforded 5-(1-hydroxy-2-iodoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 3c ). Treatment of 5-(1-hydroxy-2-chloroethyl)- ( 3a ) and 5-(1-hydroxy-2-bromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 3b ) with DAST (Et2NSF3) in methylene chloride at -40° gave the respective 5-(1-fluoro-2-chloroethyl)- ( 6a , 74%) and 5-(1-fluoro-2-bromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 6b , 65%). In contrast, 5-(1-fluoro-2-iodoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 6e ) could not be isolated due to its facile reaction with methanol, ethanol or water to yield the corresponding 5-(1-methoxy-2-iodoethyl)- ( 6c ), 5-(1-ethoxy-2-iodoethyl)- ( 6d ) and 5-(1-hydroxy-2-iodoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 3c ). Treatment of 5-(1-hydroxy-2-chloroethyl)- ( 3a ) and 5-(1-hydroxy-2-bromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 3b ) with thionyl chloride yielded the respective 5-(1,2-dichloroethyl)- ( 6f , 85%) and 5-(1-chloro-2-bromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 6g , 50%), whereas a similar reaction employing the 5-(1-hydroxy-2-iodoethyl)- compound 3c afforded 5-(1-methoxy-2-iodoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 6c ), possibly via the unstable 5-(1-chloro-2-iodoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine intermediate 6h . The 5-(1-bromo-2-chloroethyl)- ( 6i ) and 5-(1,2-dibromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 6j ) could not be isolated due to their facile conversion to the corresponding 5-(1-ethoxy-2-chloroethyl)- ( 6k ) and 5-(1-ethoxy-2-bromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 61 ). Reaction of 5-(1-hydroxy-2-bromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 3b ) with methanolic ammonia, to remove the 3′,5′-di-O-acetyl groups, gave 2,3-dihydro-3-hydroxy-5-(2′-deoxy-β-D-ribofuranosyl)-furano[2,3-d]pyrimidine-6(5H)-one ( 8 ). In contrast, a similar reaction of 5-(1-fluoro-2-chloroethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 6a ) yielded (E)-5-(2-chlorovinyl)-2′-deoxyuridine ( 1b , 23%) and 5-(2′-deoxy-β-D-ribofuranosyl)furano[2,3-d]pyrimidin-6(5H)-one ( 9 , 13%). The mechanisms of the substitution and elimination reactions observed for these 5-(1,2-dihaloethyl)-3′,5′-di-O-acetyl-2′-deoxyuridines are described.  相似文献   

4.
The syntheses of 2-methyl-5-[1′,2′,3′,4′,5′-penta-O-benzoyl-D-manno-pentitol-1′-yl]-1,3,4-oxadiazole and 5-methyl-3-[1′,2′,3′,4′,5′-penta-O-benzoyl-D-manno-pentitol-1-′yl]-1,2,4-oxadiazole, as well as their intermediate products, are described. Their 1H and 13C nmr and ms spectra are presented and their preferential conformation in solution are proposed.  相似文献   

5.
Abstract

The Zemplén degradation of 2, 3, 5, 6, 2′, 3′, 4′, 6′-octa-O-benzoylcellobiononitrile (1), -lactobiononitrile (2), and -maltobiononitrile (3) was carried out giving a mixture of the four 3-O-(D-hexopyranosyl)-D-arabinoses. Their reduction gave the 3-O-(D-hexopyranosyl)-D-arabinitols, and their benzoylation gave the 1, 2, 4, 5, 2′, 3′, 4′, 6′-octa-O-benzoyl-(D-hexopyranosyl)-D-arabinitols. Their 1H and 13C NMR spectra are described, and their conformations are determined to be planar zig-zag for the acyclic moieties.  相似文献   

6.
The tetrazoles 5-(6′-acetamido-6′-deoxy-1′,2′:3′,4′-di-O-isopropylidene-D-glycero-α-D-galactohexopyranos-6′-yl)tetrazole ( 1 ) and 5-(6′-acetamido-6′-deoxy-1′,2′:3′,4′–di-O-isopropylidene-L-glycero-α-D-galacto-hexopyranos-6′-yl)-tetrazole ( 2 ) were synthesized by the 1,3-dipolar cycloaddition reaction of the epimeric α-acetamidonitriles 5 and 6 , respectively, with sodium azide. Reaction of tetrazole 1 with acetic anhydride in the presence of pyridine afforded the N-acetyl-1,3,4-oxadiazole derivative 3 and the N-acetylacetamido-1,3,4-oxadiazole derivative 7 . The N-acetylacetamido-1,3,4-oxadiazole derivative ( 8 ) was isolated when the tetrazole 2 was allowed to react under the same conditions. The physical and spectroscopic data of the five new compounds 1, 2, 3, 7 and 8 are presented.  相似文献   

7.
The reaction of 1-O-hexadecyl-2-O-methyl-sn-glycerol with 2,3,6,2′,3′,4′,6′-hepta-O-acetyl-α-lactosylphosphoramidate or α-maltosylphos-phoramidate in the presence of trimethylsilyl triflate and molecular sieves afforded 1-O-hexadecyl-2-O-methyl-3-O-(2,3,6,2′,3′,4′,6′-hepta-O-acetyl-β-lactosyl)-sn-glycerolipid or β-maltosyl-sn-glycerolipid stereoselectively in moderate yields after column chromatography. Alkaline hydrolysis of the O-peracetyl glycerolipids gave the desired β-glycolipids 1 and 2.  相似文献   

8.
The synthesis of 2-(p-chlorophenyl)-5-[1′,2′,3′,4′,5′-penta-O-benzoyl-D-galactopentitol-1-yl]-1,3,4-oxadiazole is described. Its debenzoylation gave an equilibrium mixture of the 1,3,4-oxadiazole derivative without protection of the hydroxyl group and the N-benzoyl-D-galactono-1,4-lactonehydrazone. A similar equilibrium was observed by debenzoylation of 2-phenyl-5-[1′,2′,3′,4′,5′-penta-O-benzoyl-D-galactopentitol-1-yl]-1,3,4-oxadiazole. The 1H, 13C nmr and ms spectra of these compounds are presented.  相似文献   

9.
The synthesis of 7,8-dihydroxy-2-(2-methoxycarbonylethyl)-4,9-dioxa-2-azabicyclo[4.2.1]nonane- 3-thione ( 16 ) and of its parents 9-oxa-4-thia-3-thione 17 , and 9-oxa-4-thia-3-one 18 is described. The conversion of 5′-deoxy-5′-iodo-2′,3′-O, O-isopropylidene-5,6-dihydrouridin ( 1 ) into the 2-O-methyl-5,6-dihydrouridine 5 , the 5′-O-acetyl-5,6-dihydrouridine 4 , and into the N-(5-O-acetyl-2,3-O, O-isopropylidene-β-D -ribofuranosyl)-N-(2-methoxycarbonyl thyl)-urea ( 6 ) invoked 2′,3′-O, O-isopropylidene-2,5′-anhydro-5,6-dihydrouridine ( 2 ) as the common intermediate.  相似文献   

10.
Synthesis of Alkylphenols and -catechols from Plectranthus albidus (Labiatae) In the preceding paper, we described the isolation and structure elucidation of a series of even-numbered phenol- or pyrocatechol-derived 1-arylalkane-5-ones. To establish the assigned structures unambiguously and to have larger quantities available for physiological testing, the following compounds were prepared: in the alkylphenol series, 1-(4′-hydroxyphenyl)tetradecan-5-one ( 2a ), 1-(4′-hydroxyphenyl)hexadecan-5-one ( 2b ), and 1-(4′-hydroxyphenyl)octadecan-5-one ( 2c ); in the alkylcatechol series, 1-(3′,4′-dihydroxyphenyl)decan-5-one ( 3a ; not isolated as a natural compound), 1-(3′,4′-dihydroxyphenyl)dodecan-5-one ( 3b ), 1-(3′,4′-dihydroxyphenyl)tetradecan-5-one ( 3c ), 1-(3′,4′-dihydroxyphenyl)hexadecan-5-one ( 3d ), 1-(3′,4′-dihydroxyphenyl)octadecan-5-one ( 3e ), and 1-(3′,4′-dihydroxyphenyl)icosan-5-one ( 3f ); in the alkenylphenol series, (Z)-1-(4′-hydroxyphenyl)octadec-13-en-5-one ( 4a ) and (E)-1-(4′-hydroxyphenyl)octadec-13-en-5-one ( 4b ); in the alkenylcatechol series, (E,E)-1-(3′,4′-dihydroxyphenyl)deca-1,3-dien-5-one ( 1 ) and (Z)-1-(3′,4′-dihydroxyphenyl)octadec-13-en-5-one ( 5 ). All compounds proved to be identical with the previously assigned structures. Compound 1 was synthesized by regioselective aldol condensation of heptan-2-one with (E)-1-(3′,4′-dimethoxyphenyl)prop-2-enal ( 6d ; Scheme 1), the phenols 2a–c and the catechols 3a–f by addition of the corresponding alkyl Grignard reagent to 5-(4′-methoxyphenyl)- or 5-(3′,4′-dimethoxyphenyl)pentanal ( 17c and 18c , resp.; Scheme 4), and the olefins 4a, 4b and 5 from 17c or 18c via the 9-O-silyl-protected 13-(4′-methoxyphenyl)- or 13-(3′,4′-dimethoxyphenyl)tridecanals ( 26 and 27 , resp.) and Wittig olefination as the key steps (Scheme 5).  相似文献   

11.
Oxidation of N-aminophthalimide with lead tetra-acetate at -50° gives N-acetoxyaminophthalimide ( 3 ) which selectively aziridinates the 5,6-double bond present in 3-N-3′,5′-di-O-tribenzoyl-5-vinyl-2′-deoxyuridine ( 1a ) to yield 2-[1′-(2′-deoxy-β-D-ribofuranosyl)]-7-(1-phthalimido)-4-N-3′,5′-di-O-tribenzoyl-6-vinyl-2,4,7-triazabicyclo[4.1.0]heptan-3,5-dione ( 5 ).  相似文献   

12.
We report the synthesis of 5-[5′-(1′,2′:3′,4′-di-O-isopropylidene-β-L-arabinopyranosyl)]tetrazole, from 1,2:3,4-di-O-isopropylidene-α-D-galacto-1,6-hexodialdo-1,5-pyranose oxime via 1,2:3,4-di-O-isopropylidene-α-D-galcturononitrile as intermediate by 1,3-dipolar cycloaddition. We also report the synthesis of 5-methyl- and 5-phenyl-2-[5′-(1′,2′:3′,4′-di-O-isopropylidene-β-L-arabinopyranosyl)]-1,3,4-oxadiazole from the tetrazole derivative. The physical and spectroscopic characterizations of the heterocyclic derivatives as well as the intermedi ate nitrile and the principal by product are described and we discuss its possible formation pathway. We present the preferential conformation in solution using computational calculation and spectroscopic data.  相似文献   

13.
The hydrogenation of 2′, 3′-O-isopropylidene-5-methyluridine (1) in water over 5% Rh/Al2O3 gave (5 R)- and (5 S)-5-methyl-5, 6-dihydrouridine (2) , separated as 5′-O-(p-tolylsulfonyl)- (3) and 5′-O-benzoyl- (5) derivatives by preparative TLC. on silica gel and ether/hexane developments. The diastereoisomeric differentiation at the C(5) chiral centre depends upon the reaction media and the nature of the protecting group attached to the ribosyl moiety. The synthesis of iodo derivatives (5 R)- and (5 S)- 4 is also described. The diastereoisomers 4 were converted into (5 R)- and (5 S)-2′, 3′,-O-isopropylidene-5-methyl-2, 5′-anhydro-5, 6-dihydrouridine (7) .  相似文献   

14.
The formation of 3-(2′,2′-dimethyl-1′,3′-dioxolan-4′-yl)pyridazine ( 4 ) by reacting 1,2:5,6-di-O-isopropylidene-3-O-(p-tolylsulfonyl)-α-D-glucofuranose ( 1 ) with hydrazine hydrate via the intermediate 3-deoxy-1,2:5,6-di-O-isopropylidene-α-D-erythro-hex-3-enofuranose ( 3 ) is explained by a mechanism, involving an initial attack of the hydrazine molecule at position 4 in compound 3 , a subsequent ring opening by fission of the C4? O bond and a ring closure by formation of a N? C1 bond.  相似文献   

15.
Several porphyrinyl-nucleosides were prepared in the reaction of the OH group of one, two or four meso-p-hydroxyphenyl substituents of porphyrin with 5′-O-tosylates of 2′,3′-O-isopropylidene-adenosine or -uridine, or 5′-O-tosylthymidine; the remaining porphyrin meso-substituents were p-tolyl, p-hydroxyphenyl or 4-pyridyl. The following porphyrinyl-nucleosides were obtained with 8–17% yield: meso-di(p-tolyl)di(p-phenylene-5′-O-2′,3′-O-isopropylidene-adenosine) (or -uridine)porphyrins 1,2 , the respective meso-tetranucleosideporphyrins 3,4 -meso-mono(p-phenylene-5′-O-thymidine)porphyrins 5–7 , meso-di(p-tolyl)di(p-phenylene-5′-O-thymidine)porphyrins 8,9 and the meso-di(p-hydroxyphenyl)di(p-phenylene-5′-O-thymidine)porphyrins 10. Other compounds prepared belonged to the series: meso(4-pyridyl)4?n(p-phenylene-5′-O-2′,3′-O-isopropylideneuridine)nporphyrin, n = 1, 2 or 4, 11–13. N-Methylation gave the water soluble iodide salts: (N-methyl-4-pyridinium)44?n(p-phenylene-5′-O-2′,3′-isopropylideneuridine)nporphyrins, n = 1, 2 or 4, 14–16. The ms fab showed in most cases stepwise detachment of the CH2(5′)-nucleoside fragments. The porphyrins meso disubstituted by thymidine represent a convenient substrate for the build-up of both nucleoside units into the oligo/polynucleotide chains.  相似文献   

16.
The 1′,2′-unsaturated 2′,3′-secoadenosine and 2′,3′-secouridine analogues were synthesized by the regioselective elimination of the corresponding 2′,3′-ditosylates, 2 and 18 , respectively, under basic conditions. The observed regioselectivity may be explained by the higher acidity and, hence, preferential elimination of the anomeric H–C(1′) in comparison to H? C(4′). The retained (tol-4-yl)sulfonyloxy group at C(3′) of 3 allowed the preparation of the 3′-azido, 3′-chloro, and 3′-hydroxy derivatives 5–7 by nucleophilic substitution. ZnBr2 in dry CH2Cl2 was found to be successful in the removal (85%) of the trityl group without any cleavage of the acid-sensitive, ketene-derived N,O-ketal function. In the uridine series, base-promoted regioselective elimination (→ 19 ), nucleophilic displacement of the tosyl group by azide (→ 20 ), and debenzylation of the protected N(3)-imide function gave 1′,2′-unsaturated 5′-O-trityl-3′-azido-secouridine derivative 21 . The same compound was also obtained by the elimination performed on 2,2′-anhydro-3′-azido-3′-azido-3′-deoxy-5′-O-2′,3′-secouridine ( 22 ) that reacted with KO(t-Bu) under opening of the oxazole ring and double-bond formation at C(1′).  相似文献   

17.
The synthesis of 5-[6′-deoxy-(1′,2′:3′,4′-di-O-isopropylidene-α-D-galactopyranos-6′-yl)]tetrazole and its reaction with acetic anhydride and 1,2:3,4-di-O-isopropylidene-6-O-(4-toluenesulfonyl)-α-D-galactopyranose are described.  相似文献   

18.
The 5′-amino-5′-deoxy-2′,3′-O-isopropylideneadenosine ( 4 ) was obtained in pure form from 2′,3′-O-isopropylideneadenosine ( 1 ), without isolation of intermediates 2 and 3 . The 2-(4-nitrophenyl)ethoxycarbonyl group was used for protection of the NH2 functions of 4 (→7) . The selective introduction of the palmitoyl (= hexadecanoyl) group into the 5′-N-position of 4 was achieved by its treatment with palmitoyl chloride in MeCN in the presence of Et3N (→ 5 ). The 3′-O-silyl derivatives 11 and 14 were isolated by column chromatography after treatment of the 2′,3′-O-deprotected compounds 8 and 9 , respectively, with (tert-butyl)dimethylsilyl chloride and 1H-imidazole in pyridine. The corresponding phosphoramidites 16 and 17 were synthesized from nucleosides 11 and 14 , respectively, and (cyanoethoxy)bis(diisopropylamino)phosphane in CH2Cl2. The trimeric (2′–5′)-linked adenylates 25 and 26 having the 5′-amino-5′-deoxyadenosine and 5′-deoxy-5′-(palmitoylamino)adenosine residue, respectively, at the 5′-end were prepared by the phosphoramidite method. Similarly, the corresponding 5′-amino derivatives 27 and 28 carrying the 9-[(2-hydroxyethoxy)methyl]adenine residue at the 2′-terminus, were obtained. The newly synthesized compounds were characterized by physical means. The synthesized trimers 25–28 were 3-, 15-, 25-, and 34-fold, respectively, more stable towards phosphodiesterase from Crotalus durissus than the trimer (2′–5′)ApApA.  相似文献   

19.
ABSTRACT

The four derivatives of β-maltosyl-(1→4)-trehalose have been synthesized, which are monodeoxygenated at the site of one of the primary hydroxyl groups. The tetrasaccharides were constructed in [2+2] block syntheses. Thus, 6′″-deoxy-β-maltosyl-(1→4)-trehalose was prepared by selective iodination of allyl 2,3,6,2′,3′-penta-O-acetyl-β-maltoside (3) followed by catalytic hydrogenolysis and coupling with 2,3-di-O-benzyl-4,6-O-benzylidene-α-D-glucopyranosyl 2′,3′,6′-tri-O-benzyl-α-D-glucopyranoside (9), and 6″-deoxy-β-maltosyl-(1→4)-trehalose by selective iodination of allyl 4′,6′-O-isopropylidene-β-maltoside (14), coupling with 9, and one-step hydrogenolysis at the tetrasaccharide level. For the synthesis of 6′-deoxy-β-maltosyl-(1→4)-trehalose, the diol 2,3-di-O-benzyl-4,6-O-benzylidene-α-D-glucopyranosyl 2′,3′-di-O-benzyl-α-D-glucopyranoside (22) was selectively iodinated and glycosylated with acetobromomaltose followed by catalytic hydrogenolysis. The 6-deoxy-β-maltosyl-(1→4)-trehalose was obtained upon selective iodination of a tetrasaccharide diol.  相似文献   

20.
Seven new phenolic glucosides, 2′‐O‐acetylhenryoside ( 1 ), 2′,3′‐di‐O‐acetylhenryoside ( 2 ), 2′,6′‐di‐O‐acetylhenryoside ( 3 ), 2′,3′,6′‐tri‐O‐acetylhenryoside ( 4 ), 2′,3′,4′,6′‐tetra‐O‐acetylhenryoside ( 5 ), 2‐[(2,3‐di‐O‐acetyl‐β‐D ‐glucopyranosyl)oxy]‐6‐hydroxybenzoic acid ( 6 ), and 6‐hydroxy‐2‐[(2,3,4,6‐tetra‐O‐acetyl‐β‐D ‐glucopyranosyl)oxy]benzoic acid ( 7 ), were isolated from the leaves and stems of Viburnum cylindricum, along with 26 known compounds (henryoside=2‐(β‐D ‐glucopyranosyloxy)‐6‐hydroxybenzoic acid [2‐(β‐D ‐glucopyranosyloxy)phenyl]methyl ester). The structures of the new compounds were established on the basis of chemical and spectroscopic evidences.  相似文献   

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