Here, we report the crystal structure of d-psicose, C6H12O6, one of the rare sugars. The compound crystallizes as the β-anomer with rarely observed in pyranose carbohydrate structures trans–gauche orientation of the hydroxymethyl group relative to the pyranosyl ring. The crystal system is orth...

A facile method for the formation of branched-chain sugar derivatives is described involving the reaction of lithium dianions and carboxylic acids with keto-sugar derivatives. Acetic, propanoic, phenylacetic, 3,3-dimethylacrylic, crotonic and sorbic acids were the acids used for the preparation ...

In a novel procedure, when 3-O-benzoyl-3-C-(N-hydroxycarbamimidoyl)-1,2:4,5-di-O-isopropylidene-β-d-psicopyranose (1) is treated with acetic anhydride, chloroacetyl chloride, propanic anhydride and benzoyl chloride, the 3-O-benzoyl group undergoes an intramolecular replacement reaction with nei...

Epoxidation of alkenes by peracid, generated in situ from (2R,3S,4R,5S)-(−)-2,3:4,6-di-O-isopropylidiene-2-keto-l-gulonic acid monohydrate [(−)-DIKGA] and hydrogen peroxide by lipase catalysis induces chirality on the product epoxides with moderate to good enantioselectivity (35–71%). Alkoxy/ar...

The readily available 3-O-benzoyl-4-O-benzyl-1,2-O-isopropylidene-β-d-fructopyranose (6) was straightforwardly transformed into 5-azido-3-O-benzoyl-4-O-benzyl-5-deoxy-1,2-O-isopropylidene-β-d-fructopyranose (8), after treatment under modified Garegg's conditions followed by reaction of th...

1,2:4,5-Di-O-isopropylidene-3-C-(5-phenyl-1,2,4-oxadiazol-3-yl)-β-d-psicopyranose 14 was synthesized stereoselectively from 1,2:4,5-di-O-isopropylidene-3-C-amidoximino-3-O-benzoyl-β-d-psicopyranose 8 using a novel procedure. Treatment of 8 with acetic anhydride, chloroacetyl chloride, propanic...

A series of novel alkyl substituted fructose-based oxadiazoles were synthesized and their cytotoxic activities toward tumor cells were investigated. We studied the reaction mechanism and the stereochemistry of the reaction. Tautomerization between isomers 2 and 3 was observed in solution. The ta...

An efficient method for the stereoselective synthesis of l-ribose was accomplished starting from commercially inexpensive d-fructose. The intermediates in the process can serve as versatile precursors for the preparation of l-nucleoside analogues.

For the preparation of pure D-psicose (5a) via oxidation of 1,2:4,5-di-O-isopropylidene-β-D-fructopyranose (2a), the latter must be free from its 2,3:4,5 isomer (6a), which is oxidized to the corresponding aldosulose acetal. Pure 1,2:4,5-di-O-isopropylidene-β-D-erythro-2,3-hexodiulo-2,6-pyrano...

The addition of pyridin-2-yl-, (pyndin-2-ylmethyl)-lithium or lithium acetylide to 1,2:4,5-di-O-isopropylidene-β-d-erythro-2,3-hexodiulo-2,6-pyranose (1) affords the corresponding tertiary alcohol derivative in good yield with high stereo-selectivity. Some elimination of the 4,5-O-isopropyliden...

Soluble RNA has been prepared in relatively large amounts from rabbit liver by a procedure involving extraction of the “pH-5 enzymes” with hot NaCl. The product is highly homogeneous with respect to molecular size and heterogeneous with respect to biological activity inasmuch as it can act as ...

The crystal structure of cytidylic acid b,‡ cytidine-3′-phosphate, has been refined by the method of full matrix least-squares to an R factor of 0·045, R = Σ|Fo| − Σ|Fc|/Σ|Fo| where |Fo| and |Fc| are respectively the observed and calculated diffraction amplitudes. The nucleotide is found to...

The nucleic acids content of Aphelenchoides rutgersi, Hooper and Myers, was 0.9% DNA and 2.6% RNA dry weight. The DNA contained 29.5% adenine, 29.3% thymine, 22.5% guanine, and 18.8% cytosine, while the RNA was composed of 22.8% adenine, 23.0% uracil, 31.4% guanine, and 22.9% cytosine on a molar...

Poly 4-methyl- and poly 4,4-dimethyl-cytidylic acids have been prepared by the action of polynucleotide phosphorylase (from Micrococcus lysodeikticus) on the corresponding nucleoside 5′-pyrophosphates. Random co-polymers containing cytosine and 4-methyl- or 4,4-diamethyl-cytosine residues have ...

A series of oligomers of cytidylic acid were prepared and partially (6–9% of the bases) thiolated in the 5 positions. The modified oligomers showed increasing inhibition with increasing chain length of both the DNA polymerase-α from regenerating rat liver and the DNA-dependent RNA polymerase o...

Poly(cytidylic acid) and poly(adenylic acid) analogues, resembling closely the structures of the natural polymers, were synthesized by the alternating cyclocopolymerization of a nucleoside derivative and acrylic anhydride, and subsequent hydrolysis. The polymers catalyzed the cleavage of dinuleo...

Poly (5-fluorocytidylic acid) [poly(f5C)] has been prepared by the polymerisation of 5-fluorocytidine diphosphate with polynucleotide phosphorylase. The polymer forms a 1:1 hydrid with poly(I) and this hybrid is a good inducer of interferon. From a comparison of the melting temperatures of hybri...

Innate immunity, the first line of defense against invading pathogens, is an ancient form of host defense found in all animals, from sponges to humans. During infection, innate immune receptors recognize conserved molecular patterns, such as microbial surface molecules, metabolites produces duri...

Nucleic acids (NA) contain the genetic information and play a key role in protein biosynthesis. They are formed by the polymerization of units called nucleotides, which consist of a nitrogenous base, an aldopentose, and phosphoric acid. The base can be a pyrimidine: thymine (T), cytosine (C), an...

In this work, solid-liquid equilibrium data of binary mixtures formed by n-hexadecane, a representative compound of fossil fuels, and ethyl esters present in ethylic biodiesel (ethyl oleate, ethyl laurate, ethyl palmitate, ethyl myristate and ethyl stearate) were determined through differential ...