Heteroditopic Macrobicyclic Molecular Vessels for Single Step Aerial Oxidative Transformation of Primary Alcohol Appended Cross Azobenzenes

2021 ◽  
Author(s):  
Sayan Sarkar ◽  
Piyali Sarkar ◽  
Pradyut Ghosh
Keyword(s):  
Primary Alcohol ◽  
Single Step ◽  
Oxidative Transformation

The Fukuyama Synthesis of (−)-Lepenine

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Claisen Rearrangement ◽  
Primary Alcohol ◽  
Acid Methyl Ester ◽  
Single Step ◽  
Membered Ring ◽  
Diels Alder ◽  
Allylic Alcohol ◽  
Mannich Condensation ◽  
Open Face ◽  
Stereogenic Center

The denudatine alkaloids, exemplified by (−)-lepenine 3, have been converted chem­ically into the physiologically-active aconitine alkaloids. Tohru Fukuyama of Nagoya University envisioned (J. Am. Chem. Soc. 2014, 136, 6598) an intramolecular Mannich condensation, the conversion of 1 to 2, that in a single step would assemble two of the six rings of 3. The starting material for the synthesis was the ether 4, prepared by Mitsunobu cou­pling of the phenol with L-lactic acid methyl ester. Reduction of the ester to the alde­hyde followed by the addition of vinylmagnesium chloride led to the secondary allylic alcohol. Claisen rearrangement with triethyl orthoacetate delivered not the ether, but rather 5, the desired product of an additional Claisen rearrangement. The phenol of 5 was protected as the mesylate, that was then subjected to ozonolysis with a reduc­tive workup to give the primary alcohol. This was protected as the pivalate, which was selectively saponified. The resulting carboxylic acid was cyclized to 6 using trifluoro­acetic anhydride. The triene 7 was prepared from 6 by the addition of vinylmagnesium chloride fol­lowed by dehydration. Prospective intramolecular Diels–Alder cycloadditions that would form five-or six-membered ring lactones often fail. In the event, the cycliza­tion of 7 to the seven-membered ring lactone 8 proceeded smoothly. The tetracyclic 8 could be brought to high ee by recrystallization. Hydroboration followed by reduc­tion then delivered the diol aldehyde 9, that was converted to 1 by reductive amina­tion followed by protection and oxidation. On deprotection, 1 cyclized to the iminium salt 10. Intramolecular Mannich addi­tion of the enol form of the ketone then proceeded, to give 2. It is possible to protect tertiary amines, inter alia by formation of the adduct with a borane. In this case, transient protection as the hydrochloride was sufficient to allow oxidation of the alcohol derived from 2 to the diene 11. This was reactive enough to undergo the Diels–Alder addition of ethylene, from the more open face, leading to 12. The now-extraneous methoxy groups were then removed reductively to give 13, and the last stereogenic center of 3 was installed by hydroboration of the alkene. Methylenation of 14 followed by Luche reduction then completed the synthesis of (−)-lepenine 3.

V884: Demonstration of a Novel Single-Step Percutaneous Access Sheath for Nephrostolithotomy: A Video Presentation

2005 ◽  
Vol 173 (4S) ◽  
pp. 240-240
Author(s):  
Premal J. Desai ◽  
David A. Hadley ◽  
Lincoln J. Maynes ◽  
D. Duane Baldwin
Keyword(s):  
Single Step ◽  
Video Presentation ◽  
Percutaneous Access ◽  
Access Sheath

Effect of Lipoprotein(a) and LDL on Plasminogen Binding to Extracellular Matrix and on Matrix-dependent Plasminogen Activation by Tissue Plasminogen Activator

1996 ◽  
Vol 75 (03) ◽  
pp. 497-502 ◽  
Author(s):  
Hadewijch L M Pekelharing ◽  
Henne A Kleinveld ◽  
Pieter F C.C.M Duif ◽  
Bonno N Bouma ◽  
Herman J M van Rijn
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Binding Sites ◽  
Umbilical Vein ◽  
Single Step ◽  
Plasminogen Activation ◽  
Structural Homology ◽  
Tissue Plasminogen ◽  
Umbilical Vein Endothelial Cells

SummaryLp(a) is an LDL-like lipoprotein plus an additional apolipoprotein apo(a). Based on the structural homology of apo(a) with plasminogen, it is hypothesized that Lp(a) interferes with fibrinolysis. Extracellular matrix (ECM) produced by human umbilical vein endothelial cells was used to study the effect of Lp(a) and LDL on plasminogen binding and activation. Both lipoproteins were isolated from the same plasma in a single step. Plasminogen bound to ECM via its lysine binding sites. Lp(a) as well as LDL were capable of competing with plasminogen binding. The degree of inhibition was dependent on the lipoprotein donor as well as the ECM donor. When Lp(a) and LDL obtained from one donor were compared, Lp(a) was always a much more potent competitor. The effect of both lipoproteins on plasminogen binding was reflected in their effect on plasminogen activation. It is speculated that Lp(a) interacts with ECM via its LDL-like lipoprotein moiety as well as via its apo(a) moiety.

Purification of Urokinase from Complex Mixtures Using Immobilized Monoclonal Antibody Against Urokinase Light Chain

1983 ◽  
Vol 49 (01) ◽  
pp. 024-027 ◽  
Author(s):  
David Vetterlein ◽  
Gary J Calton
Keyword(s):  
Monoclonal Antibody ◽  
Light Chain ◽  
Culture Media ◽  
Biological Fluids ◽  
Single Step ◽  
High Yield ◽  
Step Method ◽  
Commercial Preparation ◽  
E Coli ◽  
Tissue Culture Media

SummaryThe preparation of a monoclonal antibody (MAB) against high molecular weight (HMW) urokinase light chain (20,000 Mr) is described. This MAB was immobilized and the resulting immunosorbent was used to isolate urokinase starting with an impure commercial preparation, fresh urine, spent tissue culture media, or E. coli broth without preliminary dialysis or concentration steps. Monospecific antibodies appear to provide a rapid single step method of purifying urokinase, in high yield, from a variety of biological fluids.

Distribution of Aedes aegypti and Aedes albopictus in different eco zones of Thiruvananthapuram city with special reference to dengue viremia in humans

ENTOMON ◽  
2018 ◽  
Vol 43 (4) ◽  
pp. 223-230
Author(s):  
S. Sunil Kumar ◽  
D.A. Evans ◽  
K. Muthulakshmi ◽  
T. DilipKumar ◽  
R. Heera Pillai ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Dengue Shock Syndrome ◽  
Single Step ◽  
Equal Distribution ◽  
Distribution Study ◽  
Urban Zone ◽  
High Prevalence ◽  
Vector Management ◽  
Efficient Vector

Mosquito index study of three ecologically different ecozones of the Thiruvananthapuram district, Kerala showed sharp difference on the proportionate distribution of Aedes aegypti and Aedes albopictus. Human dengue viremia (HDV) was very high in those ecozones where A.aegypti density was high and HDV was low where A.albopictus was high. In a coastal zone of Thiruvananthapuram city, A. aegypti was the most abundant vector and in a hilly, arid suburban zone, A.albopictus was the abundant vector. In the urban zone both species of mosquitoes showed equal distribution. Study on the circulating serotypes in the serum of HDV by Single step single tube Multiplex PCR showed all the four serotypes viz DENV1, DENV2, DENV3 and DENV4 in patients of Thiruvananthapuram city, which indicated the possibility of Dengue Shock Syndrome, unless there is efficient vector management. Among the four dengue serotypes, Type 1 was the most abundant virus. Abundance of microhabitats in Thiruvananthapuram city, which support A. aegypti may be the reason for high prevalence of dengue fever in the urban zone.

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