A NEW TYPE OF CARBOHYDRATE ORTHOESTER: SIDE REACTIONS OF THE KÖNIGS-KNORR SYNTHESIS

1963 ◽  
Vol 41 (12) ◽  
pp. 3074-3080 ◽  
Author(s):  
C. S. Giam ◽  
H. R. Goldschmid ◽  
A. S. Perlin
Keyword(s):  
Silver Oxide ◽  
Side Reactions ◽  
Carboxyl Group ◽  
Acetoacetic Acid ◽  
The Third ◽  
Carbohydrate Derivative ◽  
Ketene Acetal ◽  
New Type ◽  
Related Compounds ◽  
Anomeric Center

A trisaccharide orthoester (IV) is one of the products formed by decomposition of 2,3,4,6-tetra-O-acetyl α-D-mannopyranosyl bromide in the presence of silver oxide. This new type of carbohydrate derivative contains three units of D-mannose linked together through the functional groups of a molecule of acetoacetic acid. The carboxyl group of the latter takes part in the orthoester structure of IV, with one D-mannose unit closing a 1,2-orthoester ring, and another unit comprising the —OR group through its anomeric center; the keto group of the acetoacetate forms a 1,2-ketal structure with the third D-mannose unit. The n.m.r. spectra characteristics of the trisaccharide and some related compounds are described. The following sequence of reactions is consistent with formation of the trisaccharide: 1,2-trans-acetoxyl bromide [Formula: see text] 1,2-cyclic acetoxonium ion (IX)[Formula: see text] 1,2-cyclic ketene-acetal; ion IX and 2,3,4,6-tetra-O-acetyl D-mannose then added to the ketene derivative.Selective degradation of trisaccharide IV yields a novel type of ketal, i.e., 1,2,O-[1-(carbomethoxymethyl)-ethylidene]-β-D-mannose.

Synthesis and Ring Cyclization - Expansion - Contraction Reactions of Some New 2,2-Disubstituted Indan-1,3-diones and Related Compounds

2006 ◽  
Vol 59 (1) ◽  
pp. 59 ◽  
Author(s):  
Craig J. Roxburgh ◽  
Lee Banting
Keyword(s):  
Catalytic Hydrogenation ◽  
Pyridine Ring ◽  
Functional Group ◽  
Chemical Properties ◽  
Ring Expansion ◽  
Ring Structure ◽  
Side Reactions ◽  
The Third ◽  
Ring Expansion Reaction ◽  
Related Compounds

We have found that the hydrochloride of 2-phenyl-2-[2-(2-piperidyl)ethyl]-4,5,6,7-tetrahydroindan-1,3-dione 1 possesses marked analgesic activity (100% inhibition referenced to codeine) and report, as part of an extensive synthetic program, the synthesis of 38 new and structurally related compounds. Selective catalytic hydrogenation of the pyridine ring of 2-phenyl-2-[2-(2-pyridyl)ethyl]-indan-1,3-dione 2 yields the nine-membered nitrogen-containing heterocycle 6 by a novel ring cyclization–expansion reaction. The structural and functional group parameters required for this novel ring-expansion reaction have been extensively and thoroughly investigated through the synthesis of a series of structurally related compounds; principally by modification, substitution, and replacement of the various functionality contained within 2. In addition, we report the synthesis of a series of new 2-methyl-2-(ω-N-phthalimidoalkyl)-indan-1,3-diones 41, 45, and 53, two of which, like the parent 2-phenyl substituted indan-1,3-dione 2, also undergo a novel ring cyclization–expansion reaction to yield eight- and nine-membered nitrogen-containing rings. However, in these cases, further transannular reactions occur to produce the new 5,5- and 5,6-ring-fused nitrogen-containing heterocycles 44, 48 and 51, 52. Hydrazinolysis of the third, 2-methyl-2-(4-N-phthalimidobutyl)-indan-1,3-dione yields the new azepine-containing ring structure 56 by direct cyclization. Furthermore, some interesting and unexpected chemical properties of the final compounds, which include selective and non-selective pyridine-ring hydrogenations and a few unexpected side reactions, are described.

Photogeneration of Superoxide Anion upon Illumination of Purines and Pyrimidines in the Presence of Riboflavin: Structure-activity Relationships

1980 ◽  
Vol 43 (1) ◽  
pp. 19-20 ◽  
Author(s):  
MALGORZATA KORYCKA-DAHL ◽  
THOMAS RICHARDSON
Keyword(s):  
Superoxide Dismutase ◽  
Superoxide Anion ◽  
Orotic Acid ◽  
Imidazole Ring ◽  
Fluorescent Light ◽  
Carboxyl Group ◽  
Amino Group ◽  
Structure Activity ◽  
Related Compounds ◽  
Purines And Pyrimidines

Photogenerated superoxide anion might be involved in the oxidative deterioration of foods. For this reason, purines, pyrimidines and related compounds were illuminated with fluorescent light in the presence of riboflavin to examine their capacity to photogenerate superoxide anion (measured from suppression of its reduction of nitro blue tetrazolium by superoxide dismutase). Superoxide anion was photogenerated in the presence of guanine, xanthine, 6-thioguanine, thymine, uracil, 6-methyl uracil, orotic acid and 5- as well as 6-amino uracil but not in the presence of 24 other related compounds examined. Replacing the oxygen at the 6-position of guanine with sulfur or attachment of an amino group to the 5- or 6-carbon of uracil greatly increased superoxide anion generation as compared to guanine and uracil, respectively. The attachment of a carboxyl group at the 6-position of uracil augmented superoxide anion photogeneration to a much smaller extent and thymine and 6-methyl uracil did not yield any more superoxide anion than did uracil. In general, only those compounds which had an oxo group at the 6-position of purines or the 4-position of pyrimidines, and either an oxo or an amino group in the 2-position of either ring served as substrates for photogeneration of superoxide anion. Additionally, presence of purines and pyrimidines in an enol and/or amino form and an unsubstituted imidazole ring for purines were required for photogeneration of superoxide anion.

History Matters: Chinese Urbanisation as an Emergent Space

Urbanisation ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Yimin Sun ◽  
Daria Lisaia
Keyword(s):  
Communist Party ◽  
Historical Analysis ◽  
Central Committee ◽  
Labour Migration ◽  
Communist Party Of China ◽  
The Third ◽  
New Type

This article explores the process of urbanisation in China in the context of three historical transformations spanning the period 1840–2017. During the first two transformations urbanisation took place slowly, with the fragmented development of cities without a systemic character. This laid the foundation for the third historical transformation, the policy of reforms and openness in 1978, which opened up opportunities for the development of cities and stimulated a wave of internal labour migration. Over the last 30 years, urbanisation in China has acquired a huge scale, becoming a powerful tool for the development of the country’s economy. Initially a spontaneous development, in the 2000s urbanisation began to acquire a strategically planned approach. In 2014, the Central Committee of the Communist Party of China (CPC Central Committee) announced the adoption of a ‘National New-Type Urbanisation Plan’ (2014–2020), which marked a qualitative transition in terms of the management of the urbanisation process. This article argues that a nuanced historical analysis of China’s urbanisation is key to studying its urban future.

Oxygen-permselectivity in new type polyorganosiloxanes with carboxyl group on the side chain

1990 ◽  
Vol 23 (6) ◽  
pp. 637-642 ◽  
Author(s):  
Manshi Ohyanagi ◽  
Hiroyuki Nishide ◽  
Koichi Suenaga ◽  
Eishun Tsuchida
Keyword(s):  
Side Chain ◽  
Carboxyl Group ◽  
New Type

A New Type of Marine Ballast Water System Simulator

2013 ◽  
Vol 791-793 ◽  
pp. 1247-1251
Author(s):  
Feng Wei Yu ◽  
Fa Ming He ◽  
Xiao Chen Liu ◽  
Hong Ying Sun
Keyword(s):  
Ballast Water ◽  
Water System ◽  
Training System ◽  
The Third ◽  
Trouble Shooting ◽  
Software Interfaces ◽  
New Type ◽  
Third Dimension ◽  
Multi Mode ◽  
Marine Engineers

Operation and trouble shooting of ballast water system becomes a legal training item for marine engineers in STCW convention of IMO. Multi-mode simulating training system designed combines the actual devices with the simulating system. Ballast console mode improves the third dimension of training. Simulating software interfaces can meet the requirement of more trainees. The new configuration of the simulating system is benefit to the learning of actual devices. Convenient adjustment of the velocity of system process improves the efficiency of training. Several years of operation proved that the system is economical, reliable and the training effect is perfect.

Numerical Simulation on Thermal Field in the Fluidized Bed with Internal Heating Plates

2013 ◽  
Vol 690-693 ◽  
pp. 3162-3165
Author(s):  
Ji Hai Duan ◽  
Qi Wang
Keyword(s):  
Numerical Simulation ◽  
Pressure Drop ◽  
Fluidized Bed ◽  
Fluidized Beds ◽  
Thermal Field ◽  
Side Reactions ◽  
Internal Heating ◽  
New Type ◽  
Over Time

Fluidized beds are widely used in the factories. However, the traditional heating methods can not meet the actual needs. Then we propose a new type fluidized-bed, which can effectively resolve the problem occurred in conventional fluidized-bed. The temperature of the reaction gas can be distributed uniformly in the new type fluidized-bed, the bed pressure drop is relatively stable over time. The above situations are conducive to the reactions stability, and reduce the occurrence of side reactions as well.

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