María E. Gelpi

Nucleocyclitols. Synthests of Ethanolamino-Purinyl Inositol Derivatives and Their Reaction With Thionyl Chloride

Abstract The reaction of mono- and diethanolamine with a 6-chloropurinyl inositol gave 6-ethanolaminopurinyl-inositol derivatives which by reaction with thionyl chloride generated, through quaternization of N of the purine, condensed imidazo-purinyl carbocyclic nucleoside analogs.

The Reaction of Ammonia with Acyl Esters of Carbohydrates

Publisher Summary This chapter discusses the reaction of ammonia with acyl esters of carbohydrates. The processes that take place in this reaction include migrations, degradations, transesterifications, and deacylations, and their simultaneous occurrence makes the interpretation of the whole scheme very difficult. The chapter provides a general description of the facts and a discussion of the different variables that play a role in the yield of products formed and in the mechanisms involved. The reaction of acyl esters of aldoses and aldobioses with ammonia consists of a set of competitive pathways—including intramolecular 0 →N migrations of acyl groups, deacylations, and transesterifications, with formation of “aldose amides” and variable proportions of the free sugar as the principal products. Examination of acyl derivatives indicates whether a cyclic or an acyclic structure is present. A table of derivatives in the chapter, enlists the yield and properties of the products isolated from the reaction of ammonia with acylated mono- and disaccharides.

Nucleosteroids: carbocyclic nucleoside analogs of androst-4-en-17β-ol

Abstract Steroidal nucleoside analogs were synthesized starting from testosterone. By reduction of the oxime of 17β-hydroxy-androst-4-en-3-one (testosterone), a mixture of the two amino epimers of C-3 were obtained. The 3α-amino-androst-4-en-17β-ol was crystallized in 73% yield and coupled with 5-amino-4,6-dichloropyrimidine to give 3α-(5′-amino-4′-chloro-pyrimidin-6′-yl)amino-androst-4-en-17β-ol. This compound was treated with triethyl orthoformate in acid media to give the corresponding purinyl steroid adduct 3α-(6′-chloro-purin-9′-yl)-androst-4-en-17β-ol in 98% yield. This substance, in turn, was converted with good yield into the 6′-thio, 6′-methylamino, and 6′-diethyl aminopurinyl derivatives through nucleophilic reactions at C-6 of the purine nucleus.

Reaction of Peracylated Sugars with Nitriles Catalyzed by Lewis Acids

Abstract The reaction of acetylaminoacetonitrile with penta-O-benzoyl-α-D-glucopyranose in dichloromethane-nitromethane, in a 1:1 stoichiometric proportion, catalysed by stannic chloride, gave a nitrilium salt that, after hydrolysis, afforded the corresponding N-acyl glycosylamine and a mixture of several compounds originating from different competitive reactions. Among these compounds, N-benzoyl-3,5,6-tri-O-benzoyl-β-D-glucofuranosyl amine, tetra-O-benzoyl-D-glucopyranose, and octa-O-benzoyl-β-D-glucopyranosyl-(1→1)-α-D-glucopyranoside (octa-O-benzoyl-α,β-trehalose) were identified.

Nucleocyclitols. Coupling of Heterocyclic Bases to Cyclitol Oxiranes

Abstract Several nucleocyclitols were synthesized in good yield from an inositol epoxide and some activated purine derivatives (adenine, 6-methylmercaptopurine). The reaction was also carried out with other more basic, nitrogen heterocycles such as imidazole and piperidine, although side reactions can then became significant.

Nucleocyclitols. Synthesis of 3-(adenin-9-yl)-3-deoxy-1,5,6-tri-O-(methylsulfonyl)-muco-inositol

Abstract The reaction of 2,3-di- O -acetyl-1,4,5,6-tetra- O -(methylsulfonyl)- myo -inositol ( 1 ) with sodio-adenine in HCONMe 2 for 24 h at 100° gave, in 53.7% yield, the title compound, whose structure was ascertained by physical methods. Other parallel, secondary reactions were the aromatization of compound 1 to give 2,4-di- O -(methylsulfonyl)-1,2,4-benzenetriol (13.8%), and the formation of 1,5,6-tri- O -(methylsulfonyl)- muco -inositol (17.8%).

Aromatization reaction by nucleophilic attack of cyanide ion upon a sulfonylated myo-inositol

Abstract The reaction of 2,3-di- O -acetyl-1,4,5,6-tetra- O -(methylsulfonyl)- myo -inositol with potassium cyanide in 2-methoxyethanol gave as the final product, through a series of rearrangements and eliminations, 4-cyano-1- O -(methylsulfonyl)-1,2-benzene-diol, whose structure was ascertained by n.m.r. and mass spectrometry. The intermediate displacement of a mesyloxy group through intramolecular attack of an oxide anion, favored by an electrostatic-field effect of the cyano group, is postulated to explain this reaction.

Chemical and physical studies on oligosaccharides. Isolation, configurations, and conformations of the per-O-acetyl-O-β-D-glucopyranosyl-(1→3)-D-arabinoses

Abstract The reaction of octa-O-acetylcellobiononitrile with sodium methoxide, and acetylation of the resulting mixture, afforded the anomeric peracetates of O-β- D -glucopyranosyl-(1→3)- D -arabinopyranose and O-β- D -glucopyranosyl-(1→3)- D -arabinofuranose, which were isolated by fractional recrystallization. Their structures, anomeric configurations, and conformations were studied by chemical, optical, and spectroscopic methods.

Chemistry of glycosylamines. Isopropylidene acetals of N-acetyl-α-d-glucofuranosylamine

Abstract The reaction of N -acetyl-α- d -glucofuranosylamine with 2,2-dimethoxypropane, catalyzed by p -toluenesulfonic acid, gave 1-acetamido-2,3:5,6-di- O -isopropylidene-1- O -methyl- d -glucitol (65.6%), 1-acetamido-2,3- O -isopropylidene-1- O -methyl- d -glucitol (3.7%), and N -acetyl-5,6- O -isopropylidene-α- d -glucofuranosylamine (3.2% yield). The structures of these compounds were determined by chemical and spectroscopic methods, and their relation to the pattern of n.m.r. resonances of the isopropylidene methyl groups is discussed.

Chemistry of 1,1-bis(acylamido)-1-deoxyalditols. Base-catalyzed, intramolecular O,N-transacylation of per-O-acyl-1,1-bis(benzamido)-1-deoxy-d-glucitols in aprotic solvents

Abstract Penta-O-acetyl and penta-O-propanoyl derivatives of 1,1-bis(benzamido)-1-deoxy- d -glucitol are transformed into 1-acetamido-1-benzamido-1-deoxy- d -glucitol and 1-benzamido-1-deoxy-1-propanamido- d -glucitol, respectively, by heating with a suspension of potassium cyanide in acetonitrile, and subsequently O-deacylating with sodium methoxide in methanol. The reaction was also studied in the presence of a crown ether. When other nucleophiles (HO− and CH3O−) or other aprotic solvents (propanonitrile, benzene) were employed, the yields of transacylation products diminished noticeably; likewise, the use of sodium as the counter-ion significantly affected this reaction. These results are qualitatively discussed in terms of the solvent effects on the reactivity of the nucleophiles employed.