Raúl A. Cadenas

The reaction of ammonia with acylated disaccharides : Part X. Octa-O-benzoyl-lactose and other benzoyl derivatives of lactose

Abstract From the reaction of octa-O-benzoyl-lactose (1) with methanolic ammonia, lactose, 1,1-bis(benzamido)-1-deoxy-4-O-β- D -galactopyranosyl- D -glucitol (2), and N-benzoyl-4-O-β- D -galactopyranosyl- D -glucopyranosylamine (3) were obtained. The behavior of some other octabenzoylated disaccharides in the ammonolysis reaction is discussed.

Nucleosteroids: Reaction of activated purine bases with steroidal reactive centers

The reaction of 16 alpha,17 alpha-epoxy-3 beta-hydroxy-5-pregnen-20-one with 6-methyl thiopurine activated with sodium hydride leads to the coupling of the purine base with the carbonyl group at C-20 to give a steroidal nucleoside analog, which is termed nucleosteroid. In the presence of an excess of purine, a parallel reaction occurs in which the oxirane ring is opened, presumably by nucleophilic attack of an intermediate C-20 oxyanion, and yields as the main product of reaction an oligomeric mixture of nucleosteroid units linked together by ether linkages. Analogous reactions conducted with 3 beta-hydroxy-5-pregnen-20-one and with 3 beta,17 alpha-dihydroxy-5-pregnen-20-one gave minor amounts or only traces of the corresponding coupling adduct, and oligomerization did not occur. This behavior is interpreted in terms of the conformational differences showed by the different steroids to the attack by the purine.

L-sorbose benzoates. synthesis of 1,3,5-tri-O-benzoyl-α-L-sor-bopyranose

Abstract Benzoylation of L -sorbose at −10° gave 1,3,5-tri- O -benzoyl-α- L -sorbopyranose and 1,3,4,5-tetra- O -benzoyl-α- L -sorbopyranose. The structure of the former compound was established by chemical and spectroscopic methods. The preparation of 1,3,5-tri-O-benzoyl-4- O -methyl-α- L -sorbopyranose, methyl 1,3,5-tri- O -benzoyl-4- O -methyl-α- L -sorbopyranoside, and methyl 4- O -methyl-α- L -sorbopyranoside is described.

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.

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.

The reaction of penta-O-nicotinoyl-α-D-glucopyranose with aqueous ammonia

Abstract Penta-O-nicotinoyl-α- D -glucopyranose reacts with aqueous ammonia to yield N-nicotinoyl- D -glucofuranosylamine, 1-deoxy-1,1-bis(nicotinamido)- D -glucitol, and 2-( D -arabino-tetrahydroxybutyl)-6-( D -erythro-2,3,4-trihydroxybutyl)pyrazine. The structure of these compounds was ascertained by use of oxidation techniques and spectroscopic data. The formation of the pyrazine compound is discussed.