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Novel one-pot reaction conditions have been developed for the preparation of glycosyl thiourea derivatives directly from glycosyl azides mediated by a combination of sulfamic acid and sodium iodide. The reaction conditions were clean, non-toxic and the products were isolated in good to excellent yield.

A wide variety of dithioacetal derivatives of sugars can be cleaved easily into the corresponding open-chain aldehydo sugars using an efficient combination of VO(acac)(2)/H(2)O(2)/NaI at 0-5°C. Some of the salient features of this protocol are mild reaction conditions, good yields, short reaction times, easy work-up procedures, and non-involvement of toxic chemicals.

T N antigen building blocks N α -(9-fluorenylmethoxycarbonyl)- O -(3,4,6-tri- O -acetyl-2-azido-2-deoxy-α- d -galactopyranosyl)- l -serine/ l -threonine pentafluorophenyl ester [Fmoc- l -Ser/ l -Thr(Ac 3 -α- d -GalN 3 )-OPfp, 13 / 14 ] have been synthesized by two different routes, which have been compared. Overall isolated yields [three or four chemical steps, and minimal intermediary purification steps] of enantiopure 13 and 14 were 5–18% and 6–10%, respectively, based on 3,4,6-tri- O -acetyl- d -galactal ( 1 ). A byproduct of the initial azidonitration reaction of the synthetic sequence, that is, N -acetyl-3,4,6-tri- O -acetyl-2-azido-2-deoxy-α- d -galactopyranosylamine ( 5 ), has been characterized by X-ray crystallography, and shown by 1 H NMR spectroscopy to form complexes with lithium bromide, lithium iodide, or sodium iodide in acetonitrile- d 3 . Intermediates 3,4,6-tri- O -acetyl-2-azido-2-deoxy-α- d -galactopyranosyl bromide ( 6 ) and 3,4,6-tri- O -acetyl-2-azido-2-deoxy-β- d -galactopyranosyl chloride ( 7 ) were used to glycosylate N α -(9-fluorenylmethoxycarbonyl)- l -serine/ l -threonine pentafluorophenyl esters [Fmoc- l -Ser/ l -Thr-OPfp, 11 / 12 ]. Previously undescribed low-level dehydration side reactions were observed at this stage; the unwanted byproducts were easily removed by column chromatography.

2,3,4,5-Tetra- O -acetyl-1,6-dibromo-1,6-dideoxy- d -glucitol ( 1a ) obtained from d -glucitol was easily transformed into the 1,6-diiodo derivative in excellent yield (97%) by reaction with an excess of sodium iodide in refluxing butanone in 2 h. When the reaction time was prolonged to 24 h and the crude product was acetylated, 1,2,3,4,5-penta- O -acetyl-6-deoxy-6-iodo- d -glucitol and d -glucitol hexaacetate were isolated in 50 and 26% yields, respectively. The monodehalogenation then took place regioselectively at C-1. This regioselectivity allowed the synthesis of some mono- and disubstituted derivatives of d -glucitol. Thus, the peracetylated derivatives of d -glucitol, 6-bromo, 6-bromo-1- S -butyl, 6-bromo-1- S -octyl, 6- S -butyl, 6- S -butyl-1- S -octyl, 1- S -butyl, 1,6-di- S -octyl and 6- S -phenyl were synthesised in good to excellent yields. With S  as binucleophilic reagent, 1a gave mainly the thiepane derivative (75%) plus the 1- S -acetyl-2,6-anhydro- d -glucitol derivative as a by-product (10%).

Selective tosylation followed by acetylation of methyl 3-azido-2,3-dideoxy-α - d -arabino -hexopyranoside ( 1 ) in pyridine at room temperature affords a mixture of methyl 4- O -acetyl-3-azido-2,3-dideoxy-6-di- O - p -tolylsulfonyl-α- d - arabino -hexopyranoside ( 4 ) and methyl 3-azido-2,3-dideoxy-4,6-di- O - p -tolylsulfonyl-α- d - arabino -hexopyranoside ( 3 ). Compound 4 undergoes nucleophilic displacement with sodium iodide in acetic anhydride to give methyl 4- O -acetyl-3-azido-2,3,6-trideoxy-6-iodo- α - d - arabino -hexopyranoside ( 7 ), whose crystal structure and 1 H and 13 C NMR data are reported. This compound adopts the 4 C 1 conformation.

The syntheses of the following chiral compounds are described: 1 d -2,3,6-tri-, 1 d -2,4,5-tri-, 1 d -2,5,6-tri-, 1 d -1,2,3,4-tetra-, 1 d -1,2,3,6-tetra-, 1 d -1,2,4,5-tetra-, and 1 d -2,3,5,6-tetra- O -benzyl- myo -inositol; and 1 d -2,5,6-tri- O -benzyl-1- O - p -methoxybenzyl- and 1 d -2,3,5,6-tetra- O -benzyl-1- O - p -methoxybenzyl- myo -inositol. The absolute configurations were established by reference to 1 d -5,6-di- O -methyl- myo -inositol prepared from known 1 d -1,2,4-tri- O -benzyl-5,6- O -isopropylidene- myo -inositol. The preparation of the meso -derivative 2,4,5,6-tetra- O -benzyl- myo -inositol is also described. Several of the benzyl ethers were converted into protected phosphate esters by phosphitylation with bis(benzyloxy)diisopropylaminophosphine or bis(2-cyanoethoxy)diisopropylaminophosphine and subsequent oxidation with m -chloroperoxybenzoic acid. On treatment with sodium iodide in acetone, the syrupy octabenzyl esters of 2,5-di- O -benzyl- myo -inositol 1,3,4,6-tetrakisphosphate and 1 d -2,6-di- O -benzyl- myo -inositol 1,3,4,5-tetrakisphosphate were converted into the crystalline tetrasodium salts of the corresponding tetrakis(benzyl phosphates). These salts are useful compounds for hydrogenolysis to give myo -inositol tetrakisphosphates of the phosphatidylinositol cycle since phosphate migration would not be expected to occur. 1 d -3,6-di- O -octyl- myo -inositol and its racemate were prepared and each showed liquid crystalline behaviour on heating.

The crystal structure of beta-D-glucopyranosyl-(1--4)-alpha-D-glucopyranose (alpha-cellobiose) in a complex with water and NaI was determined with Mo K(alpha) radiation at 150 K to R=0.027. The space group is P2(1) and unit cell dimensions are a=9.0188, b=12.2536, c=10.9016 A, beta=97.162 degrees. There are no direct hydrogen bonds among cellobiose molecules, and the usual intramolecular hydrogen bond between O-3 and O-5' is replaced by a bridge involving Na+, O-3, O-5', and O-6'. Both Na+ have sixfold coordination. One I(-) accepts six donor hydroxyl groups and three C-H***I(-) hydrogen bonds. The other accepts three hydroxyls, one Na+, and five C-H***I(-) hydrogen bonds. Linkage torsion angles phi(O-5) and psi(C-5) are -73.6 and -105.3 degrees, respectively (phi(H)=47.1 degrees and psi(H)=14.6 degrees ), probably induced by the Na+ bridge. This conformation is in a separate cluster in phi,psi space from most similar linkages. Both C-6-O-H and C-6'-O-H are gg, while the C-6'-O-H groups from molecules not in the cluster have gt conformations. Hybrid molecular mechanics/quantum mechanics calculations show1.2 kcal/mol strain for any of the small-molecule structures. Extrapolation of the NaI cellobiose geometry to a cellulose molecule gives a left-handed helix with 2.9 residues per turn. The energy map and small-molecule crystal structures imply that cellulose helices having 2.5 and 3.0 residues per turn are left-handed.

hydroxyl groups were converted into nitrate by esters using fuming nitric acid in acetic anhydrideTe5. Benzyl2-U-benzoyl-~-~-arabinopyranoside~ 1, treated with fuming nitric acid in acetic anhydride at 20”, gave benzyl2-O-benzoyl-3,4-di-O-nitro-/3-L-arabinopyranoside 2 (58%) and benzyl2-O-benzoyld-Q-nitro-P-L-arabinopyranoside 3 (3.2%). The isolation of 3, although in Iow yield, suggests that the axial OH-4 group in 1 is more reactive than the equatorial OH-3. This behavior may be due, as has been pointed out7-‘, to intramolecular hydrogen-bonding between OH-4 and O-5, which would enhance the nucleophilic character of OH-4. Treatment of 2 with sodium iodide in acetone”.” afforded partial selective denitration’~12 at O-3, with retention of con~guration and without rearrangement, to give 3. The structure of 3 was confirmed by its transformation into benzyl 2,3-di-0~nzoyl-4-~-nitro-~-L-arabino~yranoside 4 and the subsequent denitration of 4 to give benzyl~,3-di-0-benzoyl-~~L*arabinopyranoside 5, which was identical with the product previously described%. The structure of 5 was confirmed by its reaction with methanesulfonyl chloride to give benzyl 2,3-di-0-benzoyl-4-U-methylsulfonyl-/I-L-arabinopyranoside’.

Treatment of α- L -fucose with sulfuryl chloride at low temperature gave mainly 2,3,4-tri- O -chlorosulfonyl-β- L -fucopyranosyl chloride ( 1 ) and a small proportion of the α-anomer ( 2 ). Both compounds adopt a 1 C 4 chair conformation. Methanolysis of 1 in the presence of silver carbonate and anhydrous calcium sulfate gave methyl 2,3,4-tri- O -chlorosulfonyl-α- L -fucopyranoside (the β-anomer being only present in small proportion), further converted into methyl α- L -fucopyranoside by treatment with a basic resin and a catalytic amount of sodium iodide. Methanolysis of 1 in the presence of sodium iodide gave directly methyl α- L -fucopyranoside, in a more rapid but less stereoselective way. Methanolysis of 2 in the presence of silver carbonate is very slow and gave, after removal of the chlorosulfonyl groups, methyl β- L -fucopyranoside with a rather poor stereoselectivity.

Methyl 5-deoxy-5-iodo-2,3- O -isopropylidene-β- d -ribofuranoside ( 3 ) was obtained in three steps from d -ribose. Exchange of the isopropylidene group for benzoate groups and acetolysis gave 1- O -acetyl-2,3-di- O -benzoyl-5-deoxy-5-iodo- d -ribofuranose which was coupled with 6-benzamidochloromercuripurine by the titanium tetrachloride method to afford the blocked nucleoside. Treatment with 1,5-diazabicyclo[5.4.0]undec-5-ene in N,N -dimethylformamide and removal of the blocking groups gave 9-(5-deoxy-β- d - erythro -pent-4-enofuranosyl)adenine ( 9 ). A similar route starting from methyl 5-deoxy-5-iodo-2,3- O -isopropylidene-α- d -lyxofuranoside ( 14 ) afforded the enantiomeric nucleoside, 9-(5-deoxy-β- l - erythro -pent-4-enofuranosyl)adenine ( 20 ). Methyl 2,3- O -isopropylidene-α- d -mannofuranoside was treated with sodium periodate and then with sodium borohydride to give methyl 2,3- O -isopropylidene-α- d -lyxofuranoside ( 11 ). Acid hydrolysis afforded d -lyxose. Tosylation of 11 gave methyl 2,3- O -isopropylidene-5- O - p -tolylsulfonyl-α- d -lyxofuranoside ( 12 ) which was converted into 14 with sodium iodide in acetone. Reduction of 12 gave methyl 5-deoxy-2,3- O -isopropylidene-α- d -lyxofuranoside which was hydrolyzed to give 5-deoxy- d -lyxose.

The changes induced in the chemical shifts of certain protons in some carbohydrate derivatives and some other poly-oxygenated compounds, on addition of sodium iodide to their solutions in acetone-d6, are reported. The H-1 resonances of β-glycosides of 2,3-O-isopropylidene-4-O-methyl- L -rhamnopyranoside were significantly affected by the addition of sodium ions, whereas with the α- L -glycosides, these resonances were virtually unaltered. Methoxyacetaldehyde diethyl acetal, triethyl orthoformate, and tris(2-methoxyethyl) orthoformate all showed significant induced-shifts in their acetal-proton resonances on the addition of sodium ions, and all the proton resonances of 1,4-anhydroerythritol were affected, but to differing degrees. With the cis- and trans-5-methoxy-2-phenyl-1,3-dioxanes, it is the former isomer, which can in principle simultaneously use all three oxygen atoms in the molecule to complex a sodium ion, which shows the greatest induced-shift in the acetal-proton resonance.

Methyl 5,6-dideoxy-2,3-O-isopropylidene-alpha-D-lyxo-hex-5-enofuranoside, prepared from methyl 2,3-O-isopropylidene-5,6-di-O-methylsulfonyl-alpha-D-mannofuranoside with sodium iodide in 2-butanone, was acetolyzed and the product coupled with 6-benzamidochloromercuripurine by the titanium tetrachloride method. Removal of the N-benzoyl group with pictic acid afforded 9-(2,3-di-O-acetyl-5,6-dideoxy-beta-D-xylo-hex-5-enofuranosyl)adenine. In a similar manner, methyl 5,6-dideoxy-2,3-O-isopropylidene-alpha-L-lyxo-hex-5-enofuranoside was prepared from L-mannose and converted into 9-(2,3-di-O-acetyl-5,6-dideoxy-beta-L-xylo-hex-5-enofuranosyl)adenine, further de-esterified to give the free nucleoside. 2,3:5,6-Di-O-isopropylidene-alpha-L-mannofuranosyl chloride, prepared from L-mannose, gave 9-(2,3-O-isopropylidene-alpha-L-mannofuranosyl)adenine, hydrolyzed into 9-alpha-L-mannofuranosyladenine. Treatment with methanesulfonyl chloride gave the 5',6'-dimethanesulfonate, which gave with sodium iodide in acetone the 5',6'-unsaturated nucleoside, further hydrolyzed into 9-(5,6-dideoxy-alpha-L-lyxo-hex-5-enofuranosyl)adenine.

d -Mannitol ( 1 ) was converted into 1,5-anhydro- d -mannitol, which was treated consecutively with p -toluenesulfonyl chloride (1 mol. equiv.) and benzoyl chloride (3 mol. equiv.), to produce 1,5-anhydro-2,3,4-tri- O -benzoyl-6- O - p -tolylsulfonyl- d -mannitol. 1,5-Anhydro-2,3,4-tri- O -benzoyl-6-deoxy-6-iodo- d -mannitol ( 4 ) was prepared by displacing the p -tolylsulfonyl group by reaction with sodium iodide. 1,5-Diazabicyclo[5.4.0]undec-5-ene eliminated hydrogen iodide from 4 , to yield 1,5-anhydro-2,3,4-tri- O -benzoyl-6-deoxy- d - lyxo -hex-5-enitol ( 5 ). Addition of bromine to a methanolic solution in 5 in the presence of potassium carbonate resulted in a separable mixture of methyl 1-bromo-1-deoxy-α- d -fructopyranoside ( 6 ) and methyl 1-bromo-1-deoxy-β- d -fructopyranoside ( 8 ). Dilute alkali converted 6 into methyl 1,3-anhydro-α- d -fructopyranoside, identified as its 4,5-diacetate. Dilute alkali converted 8 into methyl 1,4-anhydro-β- d -fructopyranoside.

Treatment of 2,3,4-tri-O-chlorosulfonyl-β- l -fucopyranosyl chloride (1) with benzyl 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β- d -glucopyranoside (3, in the presence of silver carbonate and a catalytic amount of silver perchlorate, gave the crystalline imidoyl derivative 6 in 83% yield. I.r., n.m.r., and m.s. data, and chemical properties are in full agreement with the proposed structure. Treatment of 6 with methanol, barium carbonate, and a catalytic amount of sodium iodide selectively gave methyl α- l -fucopyranoside (α to β 11.5:1) and benzyl 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β- d -glucopyranoside. In the presence of larger amount of silver perchlorate, the reaction between 1 and 3 gave the imidate 8. Similar results were obtained with benzyl 3,4,6-tri-O-acetyl-2-benzamido-2-deoxy-β- d -glucopyranoside.

Methyl 2-azido-3,4-di- O -benzyl-2,6-dideoxy-6-iodo-α- D -altropyranoside ( 6 ) and the corresponding 6- p -tolylsulfonyloxy compound ( 5 ) were prepared as model compounds that have both an iodine atom (or a p -tolylsulfonyloxy group) and an azido group. Compound 6 smoothly underwent selective reduction with sodium cyanoborohydride in hexamethylphosphoramide, yielding methyl 2-azido-3,4-di- O -benzyl-2,6-dideoxy-α- D -altropyranoside ( 7 ) in good yield. In contrast, 5 resisted reduction, but could also be directly converted into 7 when it was treated in the same solvent with a mixture of sodium iodide and sodium cyanoborohydride.

The behavior of methyl 4,6-O-cyclohexylidene-2-deoxy-2-trifluoroacetamido-3-O-trifluoromethylsulfonyl-α-d-glucopyranoside (6) with several reagents was examined. By reaction of 6 with lithium chloride or sodium iodide in N,N-dimethylformamide, the corresponding 3-chloro-3-deoxy- and 3-deoxy-3-iodo-allopyranosides were readily obtained. Treatment of 6 with sodium benzoate in N,N-dimethylformamide, or sodium methoxide in methanol, gave several products derived from an initially formed 2,3-allo-epimine. The difference in the foregoing reactions is explained on the basis of hydrogen bonding between 2-NHCOCF3 and 1-OMe. Solvolysis of 6 and methyl 6-benzyloxycarbonylamino-2,6-dideoxy-2-trifluoroacetamido-3-O-trifluoromethylsulfonyl-α-d- glucopyranoside (26) in hot (100°) methanol gave ring-contraction products (18, 27) having bicyclic d-xylofuranoside structures.

Heating of 2,3,5-tri- O -methyl-4- O - p -tolylsulfonyl- D -ribose diethyl dithioacetal and dibenzyl dithioacetal in aqueous pyridine gave 4- S -ethyl-2,3,5-tri- O -methyl-4-thio- l -lyxose and benzyl 2,3,5-tri- O -methyl-α-1,4-dithio- l -lyxofuranoside, respectively. Similar rearrangements to the 4-thiofuranoside were observed with 2,3,5-tri- O -methyl-4- O - p -tolylsulfonyl- D -xylose and - D -lyxose dibenzyl dithioacetals. 2,3,4-Tri- O -methyl- 5- O - p -tolylsulfonyl- D -ribose or - D -xylose dibenzyl dithioacetal, however, gave upon heating with sodium iodide in acetone 2,5-anhydro-3,4-di- O -methyl- D -ribose or - D -xylose dibenzyl dithioacetal, respectively.

Reaction of 1,4:3,6-dianhydro-2,5-di-O-mesyl- and -tosyl- D -mannitol with sodium iodide gave a 1:1 mixture of 2,5-dideoxy-2,5-diiodo- D -glucitol (12) and - L -iditol (22). 1,4:3,6-Dianhydro-2-deoxy-2-iodo-5-O-mesyl- D -glucitol (13) and the corresponding D -mannitol derivative (9) are formed as intermediates. Both 9 and 13, as well as 12 and 22, are rapidly isomerized to a mixture of the two in the presence of iodide, proving a fast iodo-iodo substitution reaction. This is restricted to starting materials having the mannitol configuration, as the corresponding 2,5-di-O-mesyl- D -glucitol derivative gives only the known 5-deoxy-5-iodo- L -iditol derivative. The possible mechanism of the unusual isomerization reactions is discussed.

Treatment of 6-chloro-6-deoxycellulose with sodium iodide in 2,5-hexanedione gave 6-deoxy-6-iodocellulose; >80% of the chlorine atoms were replaced. 6-Deoxy-6-iodo- d -glucose was identified by g.l.c.-m.s. in hydrolyzates of deoxyiodocellulose. Acetylated 6-deoxy-6-iodocellulose was converted almost quantitatively into 5,6-cellulosene acetate, which was characterized by hydrolyzing the product and converting the resultant dicarbonyl sugar into an isopropylidene acetal 10 . The changes of molecular-weight distribution during iodination and dehydroiodination were investigated by gel-permeation chromatography.

Acetylation and benzoylation of dehydro- l -ascorbic acid phenylhydrazone result in the formation of olefinic derivatives; treatment of the bis(phenylhydrazone) mono- p -toluenesulfonate with sodium iodide affords an anhydro derivative having a diazine ring.

The crystalline complexes 2NaI·α-cellobiose, NaI·α-cellobiose·2H 2 O, NaI·α-isomaltose, and NaBr·α-isomaltose have been isolated. Sodium iodide adducts were used to prepare crystalline α-cellobiose (98% α) and amorphous α-isomaltose (90% α), previously inaccessible anomeric forms. The disaccharides and their complexes were analyzed for anomeric content by g.l.c., and characterized by polarimetry and n.m.r. and i.r. spectroscopy. The strong influence of sodium iodide on the optical rotation of a number of carbohydrates suggests that complexation with sodium iodide can affect molecular conformation.

Treatment of sucrose octamethanesulphonate (1) with either sodium chloride or mesyl chloride in N,N-dimethylformamide gave a mixture of 6- and 6′-monochloro-monodeoxysucrose heptamethanesulphonates (6) and 6,6′-dichloro-6,6′-dideoxysucrose hexamethanesulphonate (7). A crystalline mixture of 6- and 6′-monoiodo derivatives 8 was obtained when 1 was treated with sodium iodide in butanone. Reaction of 1 with sodium bromide under various conditions gave a mixture of 6- and 6′-monobromo-monodeoxysucrose heptamethanesulphonates (2), 6,6′-dibromo-6,6′-dideoxysucrose hexamethanesulphonate (3), and, probably, 6-bromo-6-deoxy-1,3,4-tri-O-mesyl-β- D -fructofuranosyl 4,6-dibromo-4,6-dideoxy-2,3-di-O-mesyl-α- D -galacto-pyranoside (4). Reduction of mixture 2 afforded a crystalline monodeoxysucrose heptamethanesulphonate (5) containing equimolar amounts of the 6- and 6′-monodeoxy isomers. Similarly, 3 gave 6,6′-dideoxysucrose hexamethanesulphonate 9 which, on treatment with sodium azide in hexamethylphosphoric triamide, underwent selective nucleophilic substitution at C-4 to give 6-deoxy-β- D -fructofuranosyl 4-azido-4,6-dideoxy-α- D -galactopyranoside pentanesulphonate (10). Sodium azide reacted with the octasulphonate 1 in hexamethylphosphoric triamide to give the 4,6,6′-triazide 11 and 1′,4,6,6′-tetra-azide 12. The triazide 11 was also obtained when 6,6′-dideoxy-6,6′-di-iodosucrose hexamethanesulphonate was treated with sodium azide in hexamethylphosphoric triamide. The secondary 4-mesyloxy substituent is therefore more reactive to nucleophilic substitution than that at the primary 1′-position in 1.

3-Azido-1,2:5,6-di- O -cyclohexylidene-3-deoxy-α- d -glucofuranose was easily reduced to the corresponding amino sugar with zinc dust in boiling aqueous N,N -dimethylformamide. 2-Azido-1,2- O -cyclohexylidene-3-deoxy-5,6-di- O -methylsulfonyl-α- d -glucofuranose was converted into 1,2- O -cyclohexylidene-3,6-dideoxy-3,6-epimino-5- O -methylsulfonyl-α- d -glucofuranose by treatment with sodium iodide and zinc dust in boiling aqueous N,N -dimethylformamide, whereas 3-azido-1,2- O -cyclohexylidene-3-deoxy-6- O - p -tolylsulfonyl-α- d -glucofuranose was converted into 3-amino-1,2- O -cyclohexylidene-5,6-didehydro-3,5,6-trideoxy-α- d - xylo -hexofuranose by the same treatment. The mechanisms of these two reactions were investigated; the present results suggest the neighboring participation of the azido group.

The action of sodium iodide in acetone on methyl 4- O -benzyl-3-deoxy-3-iodo-2- O -tosyl-β- l -xylopyranoside ( 1 ) is described. At room temperature, methyl 4- O -benzyl-2,3-dideoxy-β- l - glycero -pent-2-enoside ( 2 ) and methyl 2- O -benzyl-3,4-dideoxy-β- l - glycero -pent-e-enoside ( 2a ) were formed. At lower temperatures (0–5°), the action of sodium iodide in acetone on 1 produces only the expected 2,3-alkene 2 , and a mechanism, based on conformational analysis, is suggested to account for this fact. The action of sodium iodide in acetone on methyl 4- O -benzyl-3-deoxy-3-iodo-2- O -tosyl-6- O -trityl-α- d -glucopyranoside [ 12 , made from the iodohydrin 9 obtained by the action of methylmagnesium iodide on methyl 2,3-anhydro-4- O -benzyl-6- O -trityl-α- d -allopyranoside ( 8 )] is also described. The structure of the iodohydrin 9 was established by mild, acid hydrolysis, followed by sequential hydrogenolysis, to yield methyl 3-deoxy-α- d - ribo -hexopyranoside. Treatment of 12 with sodium iodide in refluxing acetone yielded a crystalline alkene, which has an n.m.r. spectrum consistent with the structure of methyl 4- O -benzyl-2,3-dideoxy-6- O -trityl-α- d - erythro -hex-2-enoside ( 13 ). This structure was further confirmed by cis hydroxylation of 13 with neutral potassium permanganate, followed by catalytic hydrogenolysis, to give methyl α- d -mannopyranoside.

A crystalline disaccharide derivative containing β-(1 → 6)-linked 2-amino-2-deoxy- d -glucose and muramic acid: 2-acetamido-6- O -(2-acetamido- 3,4 ,6-tri- O -acetyl-2-deoxy-β- d -glucopyranosyl)- i , 4 -di- O -acetyl-2-deoxy-3- O -[ d-i -(methyl carboxylate)ethyl]-α- d -glucopyranose (VIII), was synthesized. 2-Acetamido- 3 - O -( d-i -carboxyethyl)-2-deoxy-α- d -glucose ( N -acetylmuramic acid) was esterified with diazomethane, tritylated, acetylated, and detritylated, to give 2-acetamido- i , 4 -di- O -acetyl-2-deoxy-3- O -[ d-i -(methyl carboxylate)ethyl]-α- d -glucopyranose (V). p -Toluenesulfonylation of V, followed by reaction with sodium iodide showed that position 6 was free. Condensation of V with 2-acetamido- 3,4 ,6-tri- O -acetyl-2-deoxy-α- d -glucopyranosyl bromide gave VIII in 6% yield.

Opening of the epoxide ring of methyl 3,3′-anhydro-2-benzamido-4,6- O -benzylidene-2-deoxy-3- C -(hydroxymethyl)-α- D -allopyranoside ( 1 ) with sodium iodide, in the presence of acetic anhydride and p -toluenesulfonic acid, gave methyl 3- O -acetyl-2-benzamido-4,6- O -benzylidene-2-deoxy-3- C -(iodomethyl)-α- D -allopyranoside ( 2 ). Reduction of 2 with powdered zinc in buffered N,N -dimethylformamide gave methyl 2-benzamido-4,6- O -benzylidene-2,3-dideoxy-3- C -methylene-α- D - ribo -hexopyranoside ( 3 ) in 92% yield. Treatment of 1 with zinc in acetic acid containing sodium iodide afforded 3 directly in 90% yield. Hydroboration-oxidation of 3 gave a mixture of methyl 2-benzamido-4,6- O -benzylidene-2-deoxy-3- C -methyl-α- D -glucopyranoside ( 6 ), and the corresponding 3-deoxy-3- C -(hydroxymethyl) derivatives ( 4 ). Chromatographic separation of the isomers afforded one of the 3-deoxy-3- C -(hydroxymethyl) 3-epimers as a pure oil, and 6 as an impure oil. Acetylation of the former with acetic anhydride in pyridine gave the 3-deoxy-3 C -(acetoxymethyl) derivative ( 5 ), and acetylation of 6 with acetic anhydride containing p -toluenesulfonic acid gave crystalline methyl 3- O -acetyl-2-benzamido-4,6- O -benzylidene-2-deoxy-3- C -methyl-α- D -glucopyranoside ( 7 ).

Reaction of bis[3- O -(chloromethylsulfenyl chloride)-1,2:5,6-di- O -isopropylidene-α- d -glucofuranose] disulfide ( 2 ) with sodium iodide g

Chlorination of 3,4,6-tri- O -acetyl- d -glucal in daylight afforded 3,4,6-tri- O -acetyl-2-chloro-2-deoxy-α- d -glucopyranosyl chloride (2) and 3,4,6-tri- O -acetyl-2-chloro-2-deoxy-β- d -mannopyranosyl chloride (3) in the ratio ca. 4:1. Hydrolysis of compound 2 with hydrochloric acid gave 2-chloro-2-deoxy- d -glucose in high yield, thereby providing a much-improved route to this compound. The mannosyl chloride 3 afforded 2-deoxy- d - arbino - d -hexose, with evolution of chlorine, on treatment with hydrochloric acid, and 3,4,6-tri- O -acetyl- d -glucal on treatment with sodium iodide in acetone. Dehydrohalogenation of the glucosyl chloride 2 with triethylamine afforded 3,4,6-tri- O -acetyl-2-chloro-1,2-dideoxy- d - arabino -hex-1-enopyranose, chlorination of which gave 3,4,6-tri- O -acetyl-2,2-dichloro-2-deoxy- d - arabino -hexosyl chloride. Hydrolysis of the trichloro derivative with hydrochloric acid yielded crystalline 2,2-dichloro-2-deoxy- d - arabino -hexose.

Treatment of acetylated glycosyl bromides of d -galactose, d -glucuronic acid, and d -xylose with potassium methyl- and benzyl-xanthates in alcohol affords the corresponding glycosyl methyl- and benzyl-xanthates respectively. The same condensation in acetone yields the corresponding 1-thioglycosides and diglycosyl sulfides instead of glycosyl xanthates. The glycosyl xanthates, on heating with sodium iodide in acetone, give the corresponding 1-thioglycosides in high yield. The mechanism of decomposition of glycosyl xanthates is discussed in detail.

3',4',-Dideoxykanamycin B, the kanamycin B derivative that is active against resistant bacteria, was prepared from kanamycin B via N-tosylation, 3',4'-O-sulphonylation, 3',4'-unsaturation, and hydrogenation. The unsaturated intermediate was obtained from the 3',4'-di-O-sulphonyl derivatives by the action of sodium iodide in N,N-dimethylformamide; if zinc dust was added in this reaction, aziridine derivatives were formed. Removal of the tosyl group was successfully performed by using sodium in ammonia-ethylamine.