scholarly journals Intramolecular Nitrile Oxide—Alkene Cycloaddition of Sugar Derivatives with Unmasked Hydroxyl Group(s).

ChemInform ◽  
2007 ◽  
Vol 38 (29) ◽  
Author(s):  
Tony K. M. Shing ◽  
Wai F. Wong ◽  
Hau M. Cheng ◽  
Wun S. Kwok ◽  
King H. So
Keyword(s):  
Nitrile Oxide ◽  
Hydroxyl Group ◽  
Sugar Derivatives

Intramolecular Nitrile Oxide−Alkene Cycloaddition of Sugar Derivatives with Unmasked Hydroxyl Group(s)

2007 ◽  
Vol 9 (5) ◽  
pp. 753-756 ◽  
Author(s):  
Tony K. M. Shing ◽  
Wai F. Wong ◽  
Hau M. Cheng ◽  
Wun S. Kwok ◽  
King H. So
Keyword(s):  
Nitrile Oxide ◽  
Hydroxyl Group ◽  
Sugar Derivatives

New Strategy of Synthesis of Peramivir Analogues as Potential Neuraminidase Inhibitors

Synthesis ◽  
2019 ◽  
Vol 52 (06) ◽  
pp. 933-941
Author(s):  
Roberta Bartolotta ◽  
Concetta La Rosa ◽  
Donatella Nava
Keyword(s):  
Cycloaddition Reaction ◽  
Nitrile Oxide ◽  
Hydroxyl Group ◽  
Dipolar Cycloaddition ◽  
Carbon Nucleus ◽  
Neuraminidase Inhibitors ◽  
Subsequent Reaction ◽  
New Strategy

Highly functionalised potential neuraminidase (NA) inhibitors, analogues of peramivir, were synthesised via a new and versatile method starting from a stereoselective 1,3-dipolar cycloaddition reaction between the nitrile oxide derived from 2-ethylbutanal and the commercially available and inexpensive cyclopentadiene and 1,3-cyclohexadiene, which afforded the isoxazolino-cyclopentene or cyclohexene intermediates, respectively. The subsequent reaction of the C=C bond in different conditions allowed the functionalisation of the five (or six) membered carbon nucleus. Further functionalised derivatives displaying an amino and a hydroxyl group were achieved via the final opening of the isoxazoline ring.

scholarly journals Structural requirements for binding to the sugar-transport system of the human erythrocyte

1973 ◽  
Vol 131 (2) ◽  
pp. 211-221 ◽  
Author(s):  
J. E. G. Barnett ◽  
G. D. Holman ◽  
K. A. Munday
Keyword(s):  
Transport System ◽  
Human Erythrocyte ◽  
Sugar Transport ◽  
Hydroxyl Group ◽  
Structural Requirements ◽  
Glucose Molecule ◽  
Inhibition Constants ◽  
Polar Substituents ◽  
Sugar Derivatives ◽  
Potential Substrate

The structural requirements for binding to the glucose/sorbose-transport system in the human erythrocyte were explored by measuring the inhibition constants, Ki, for specifically substituted analogues of d-glucose when l-sorbose was the penetrating sugar. Derivatives in which a hydroxyl group in the d-gluco configuration was inverted, or replaced by a hydrogen atom, at C-1, C-2, C-3, C-4 or C-6 of the d-glucose molecule, all bound to the carrier, confirming that no single hydroxyl group is essential for binding to the carrier. The binding and transport of 1-deoxy-d-glucose confirmed that the sugars bind in the pyranose form. The relative inhibition constants of d-glucose and its deoxy, epimeric and fluorinated analogues are consistent with the combination of β-d-glucopyranose with the carrier by hydrogen bonds at C-1, C-3, probably C-4, and possibly C-6 of the sugar. Both polar and non-polar substituents at C-6 enhance the affinity of d-glucose derivatives relative to d-xylose, and d-galactose derivatives relative to l-arabinose, and it is suggested that the carrier region around C-6 of the sugar may contain both hydrophobic and polar binding groups. The spatial requirements at C-1, C-2, C-3, C-4 and C-6 were explored by comparing the relative binding of d-glucose and its halogeno and O-alkyl substituents. The carrier protein closely approaches the sugar except at C-3 in the d-gluco configuration, C-4 and C-6. d-Glucal was a good inhibitor, showing that a strict chair form is not essential for binding. 3-O-(2′,3′-Epoxypropyl)-d-glucose, a potential substrate-directed alkylating agent, bound to the carrier, but did not inactivate it.

scholarly journals Flüssigkristalline Kohlenhydratdithioacetale / Liquid Crystalline Carbohydrate Dithioacetals

1988 ◽  
Vol 43 (7) ◽  
pp. 878-888 ◽  
Author(s):  
Andreas Eckert ◽  
Bernd Kohne ◽  
Klaus Praefcke
Keyword(s):  
Molecular Structure ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
The Other ◽  
Hydroxyl Group ◽  
Melting Behaviour ◽  
Sugar Chain ◽  
Alkyl Chains ◽  
Identical Type ◽  
Sugar Derivatives

Abstract S,S-dialkyl acetals of hexanal and numerous aldoses, tripodal in structure, have been synthesized, characterized and investigated by optical microscopy and D.S.C. Most of these geminal dithioacetals show a complicated melting behaviour and are thermotropic liquid crystal-line, exhibiting only one smectic-like phase of identical type. This mesophase is not miscible with the SAd -Phase of other amphiphilic sugar-based liquid crystals. As shown in a homologues series of D-glucose S,S-dialkylacetal derivatives clearing points are rising as function of growing number n of carbon atoms in their S-alkyl chains. With constant n given a similar trend is observed by varying the length of the polar, hydrophilic sugar units. Regarding stereochemistry the dithioderivatives 5 and 12 of the pentose or hexose series, respectively, with a configuration related to that of D-mannose exhibit relatively the most stable mesophase. However, the most stable mesophase of all investigated sugar dithioderivatives is exhibited by the heptose S,S-dialkylacetal 13. Surprisingly, derivative 10 of L-rhamnose (6-desoxy-L-mannose) - the terminal hydroxyl group in the sugar chain of mannose is missing! -showed to be non-mesomorphic, demonstrating that a terminal hydroxyl group of these sugar derivatives seems to be essential for exhibiting a mesophase. On the other hand, as shown with the dithioderivative 9 of 2-desoxy-D-glucose in comparison to the derivative 8e and 12 of D-glucose or D-mannose, respectively, their clearing points seem to be less, although differently effected if an internal hydroxyl group - for instance here at C-2 - has been stripped off.Melting behaviour as well as thermomesogenic properties of the presented amphiphilic carbo-hydrate liquid crystals in relationship to their molecular structure are discussed in detail.

Reactions of nitro sugars. XII. A novel type of disaccharide synthesis

1969 ◽  
Vol 47 (15) ◽  
pp. 2819-2826 ◽  
Author(s):  
Hans H. Baer ◽  
Frank Kienzle
Keyword(s):  
Ethylenic Bond ◽  
Hydroxyl Group ◽  
Reaction Conditions ◽  
Free Hydroxyl ◽  
Sugar Derivatives ◽  
Derivatives Of

Nitro disaccharide methyl glycosides were obtained by base-catalyzed addition of partially blocked sugar derivatives having one free hydroxyl group, across the ethylenic bond in methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-β-D-erythro-hex-2-enopyranoside (1) and its α-anomer (2). Thus, the addition of 2,3,4,6-tetra-O-acetyl-β-D-glucopyranose (3) gave blocked derivatives of sophorose, namely methyl 2-O-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-4,6-O-benzylidene-3-deoxy-3-nitro-β-D-glucopyranoside (4) and -α-D-glucopyranoside (5). Similarly, the use of methyl 4,6-O-benzylidene-3-deoxy-3-nitro-β-D-glucopyranoside (10) and its α-anomer (13) as addends led to 2 → 2 linked bisglycosidyl ethers; these were the methyl 4,6-O-benzylidene-3-deoxy-2-O-(methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-D-gluco-pyranosid-2-yl)-3-nitro-D-glucopyranosides with the anomeric configurations β,β, α,α, and α,β (11, 14, and 15, respectively). Methyl 4,6-O-benzylidene-3-deoxy-3-nitro-β-D-mannopyranoside (12) was found to epimerize to 10 under the reaction conditions; therefore, interaction of 12 and 1 also gave the bis-β-D-glucosidyl ether (11). The L-enantiomer of 12 gave with 1 an optically inactive meso compound (16) possessing a β-L- and a β-D-glucosidyl moiety.

Detection method of combustion oscillation characteristics under strong noise background

2020 ◽  
Vol 21 (6) ◽  
pp. 612
Author(s):  
Yunkun Wei ◽  
Tianhong Zhang ◽  
Zhonglin Lin ◽  
Qi Xie ◽  
Yan Zhang
Keyword(s):  
Radiation Thermometry ◽  
Hydroxyl Group ◽  
Interference Signal ◽  
Engine Vibration ◽  
Combustion Technology ◽  
Lean Fuel ◽  
Combustion Oscillation ◽  
Aero Engines ◽  
Temperature Measurement System ◽  
Multispectral Radiation Thermometry

After the lean fuel premixed combustion technology is applied to aero engines, severe combustion oscillations will be cased and led to hidden safety hazards such as engine vibration, further energy waste and other problems. Therefore, it is increasingly important to actively control combustion oscillations. In this paper, a multispectral radiation thermometry (MRT) is used to analyze the hydroxyl group, which is a measurable research object in the combustion chamber of an aero engine, and to fit the functional relationship between the radiation intensity ratio and the temperature in different bands. The theoretical value of the error is <2%. At the same time, in order to solve the problem of weak detection signal and excessive interference signal, an improved frequency domain filtering method based on fast Fourier transform is designed. Besides, the FPGA platform is used to ensure the real-time performance of the temperature measurement system, and simulations and experiments are performed. An oscillating signal with an oscillation frequency of 315 Hz is obtained on the established test platform, and the error is only 1.42%.

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