New approach to the synthesis of optically active trityl systems

1969 ◽  
Vol 47 (21) ◽  
pp. 4073-4076 ◽  
Author(s):  
K. G. Rutherford ◽  
J. L. H. Batiste ◽  
J. M. Prokipcak
Keyword(s):  
Michael Reaction ◽  
Sodium Hydride ◽  
Optically Active ◽  
New Method ◽  
New Approach

A new method for the resolution of potentially optically active trityl alcohols is reported. Three trityl alcohols as pilot compounds were converted to hydracrylic acid derivatives. Esterification with diazo-methane was followed by degradation (reverse Michael reaction) to the original alcohols with sodium hydride. The resolution of phenyl-α-naphthyl-p-tolylcarbinol was effected conveniently by this route.

Copper-catalyzed substitution of allylic carbonates with diboron: A new approach to allylboronate synthesis

2008 ◽  
Vol 80 (5) ◽  
pp. 1039-1045 ◽  
Author(s):  
Hajime Ito ◽  
Shinichiro Ito ◽  
Yusuke Sasaki ◽  
Kou Matsuura ◽  
Masaya Sawamura
Keyword(s):  
Optically Active ◽  
New Method ◽  
Efficient Synthesis ◽  
Chirality Transfer ◽  
New Approach ◽  
Highly Efficient ◽  
Selective Substitution

Copper-catalyzed γ-selective substitution of allylic carbonates with diboron provides a new method for the efficient synthesis of allylboronates. Optically active α-chiral allylboronates were synthesized through the reaction of chiral allylic carbonates with bis(pinacolato)diboron in the presence of achiral Cu(I)-catalyst with highly efficient chirality transfer. Additionally, in the presence of a chiral Cu(I) catalyst, optically active α-chiral allylboronates were obtained with >90 % ee through the reaction of prochiral substrates with the diboron.

A New Approach for the Analysis of Mixture Toxicity Data

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2345-2348 ◽  
Author(s):  
C. N. Haas
Keyword(s):  
Quantitative Analysis ◽  
Mixture Toxicity ◽  
New Method ◽  
Metal Exposure ◽  
Positive Interactions ◽  
Toxicity Data ◽  
Data Set ◽  
New Approach ◽  
Negative Interactions

A new method for the quantitative analysis of multiple toxicity data is described and illustrated using a data set on metal exposure to copepods. Positive interactions are observed for Ni-Pb and Pb-Cr, with weak negative interactions observed for Ni-Cr.

New Approach to the Theory of Circular Dichroism

1998 ◽  
Vol 63 (8) ◽  
pp. 1187-1201 ◽  
Author(s):  
Jaroslav Zamastil ◽  
Lubomír Skála ◽  
Petr Pančoška ◽  
Oldřich Bílek
Keyword(s):  
Electromagnetic Wave ◽  
Circular Dichroism ◽  
Electromagnetic Waves ◽  
Maxwell Equations ◽  
Optically Active ◽  
Semiclassical Approach ◽  
New Approach ◽  
Isotropic Media ◽  
New Formula ◽  
Circular Dichroïsm

Using the semiclassical approach for the description of the propagation of the electromagnetic waves in optically active isotropic media we derive a new formula for the circular dichroism parameter. The theory is based on the idea of the time damped electromagnetic wave interacting with the molecules of the sample. In this theory, the Lambert-Beer law need not be taken as an empirical law, however, it follows naturally from the requirement that the electromagnetic wave obeys the Maxwell equations.

scholarly journals New Method for Generating New Families of Distributions

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 726
Author(s):  
Lamya A. Baharith ◽  
Wedad H. Aljuhani
Keyword(s):  
Exponential Distribution ◽  
Real Data ◽  
Rate Function ◽  
New Method ◽  
Likelihood Method ◽  
Alpha Power ◽  
Unknown Parameters ◽  
Failure Rate Function ◽  
New Approach ◽  
Numerical Studies

This article presents a new method for generating distributions. This method combines two techniques—the transformed—transformer and alpha power transformation approaches—allowing for tremendous flexibility in the resulting distributions. The new approach is applied to introduce the alpha power Weibull—exponential distribution. The density of this distribution can take asymmetric and near-symmetric shapes. Various asymmetric shapes, such as decreasing, increasing, L-shaped, near-symmetrical, and right-skewed shapes, are observed for the related failure rate function, making it more tractable for many modeling applications. Some significant mathematical features of the suggested distribution are determined. Estimates of the unknown parameters of the proposed distribution are obtained using the maximum likelihood method. Furthermore, some numerical studies were carried out, in order to evaluate the estimation performance. Three practical datasets are considered to analyze the usefulness and flexibility of the introduced distribution. The proposed alpha power Weibull–exponential distribution can outperform other well-known distributions, showing its great adaptability in the context of real data analysis.

Synthesis and Selected Transformation of Optically Active Cyclopentenyl Sulfoxides: New Approach to Optically Active Cyclopentenones.

ChemInform ◽  
2007 ◽  
Vol 38 (27) ◽  
Author(s):  
W. H. Midura ◽  
J. Krysiak ◽  
M. W. Wieczorek ◽  
A. Filipczak
Keyword(s):  
Optically Active ◽  
New Approach

Comparison of New Telescopic Video Microlaryngoscopic and Standard Microlaryngoscopic Techniques

1992 ◽  
Vol 101 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Eiji Yanagisawa ◽  
Ken Yanagisawa ◽  
Jay B. Horowitz ◽  
Lawrence J. Mambrino
Keyword(s):  
Video Camera ◽  
New Method ◽  
Depth Of Field ◽  
Microscopic Technique ◽  
New Approach ◽  
Advantages And Disadvantages ◽  
Laryngeal Surgery ◽  
Valuable Method ◽  
Microlaryngeal Surgery ◽  
Television Image

A new approach to microlaryngeal surgery using a specially designed video microlaryngoscope with a rigid endoscopic telescope and an attached video camera was introduced by Kantor et al in 1990. The ability to video document and perform surgery of the larynx by viewing a high-resolution television image was demonstrated. This method was recommended over the standard microscopic technique for increased visibility with greater depth of field, unimpeded instrument access, instant documentation, and superior teaching value. The authors tried this new method and the standard microscopic technique at the same sitting on a series of patients. This paper will compare these two different techniques and discuss their advantages and disadvantages. Although the new method has many advantages, the standard microscopic technique remains as a valuable method in laryngeal surgery.

Inferring age from otolith measurements: a review and a new approach

2004 ◽  
Vol 61 (7) ◽  
pp. 1269-1284 ◽  
Author(s):  
RIC Chris Francis ◽  
Steven E Campana
Keyword(s):  
Simulation Experiment ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
New Method ◽  
Population Parameters ◽  
Benefit Analysis ◽  
Mixture Analysis ◽  
New Approach ◽  
Individual Fish ◽  
The Cost

In 1985, Boehlert (Fish. Bull. 83: 103–117) suggested that fish age could be estimated from otolith measurements. Since that time, a number of inferential techniques have been proposed and tested in a range of species. A review of these techniques shows that all are subject to at least one of four types of bias. In addition, they all focus on assigning ages to individual fish, whereas the estimation of population parameters (particularly proportions at age) is usually the goal. We propose a new flexible method of inference based on mixture analysis, which avoids these biases and makes better use of the data. We argue that the most appropriate technique for evaluating the performance of these methods is a cost–benefit analysis that compares the cost of the estimated ages with that of the traditional annulus count method. A simulation experiment is used to illustrate both the new method and the cost–benefit analysis.

Heteroepitaxy and Characterization of Low-Dislocation-Density GaN on Periodically Grooved Substrates

2000 ◽  
Vol 639 ◽  
Author(s):  
T. Detchprohm ◽  
M. Yano ◽  
R. Nakamura ◽  
S. Sano ◽  
S. Mochiduki ◽  
...  
Keyword(s):  
Dislocation Density ◽  
New Method ◽  
Growth Technique ◽  
New Approach ◽  
Density Area ◽  
Low Dislocation Density ◽  
Dislocation Densities ◽  
Movpe Growth

ABSTRACTWe have developed a new method to prepare low-dislocation-density GaN by using periodically grooved substrates in a conventional MOVPE growth technique. This new approach was demonstrated for GaN grown on periodically grooved α-Al2O3(0001), 6H-SiC(0001)Si and Si(111) substrates. Dislocation densities were 2×107 cm−2 in low-dislocation-density area.

A new approach to the stereoselective synthesis of trans-3-carbamoyl-β-lactam moieties

2017 ◽  
Vol 41 (6) ◽  
pp. 2479-2489 ◽  
Author(s):  
Anna Zakaszewska ◽  
Ewelina Najda-Mocarska ◽  
Sławomir Makowiec
Keyword(s):  
Stereoselective Synthesis ◽  
Optically Active ◽  
Thermal Generation ◽  
New Approach

Optically active 1,4-disubstituted-3-carbamoyl-azetidinones are synthesized from 5-[(N-arylamino)(hydroxyl)methylene]-2,2-dimethyl-1,3-dioxa-4,6-diones and chiral aldimines via thermal generation of carbamoyl ketenes and subsequent [2+2] cycloaddition.

scholarly journals A New Approach to Gauging Inflation Expectations

2009 ◽  
pp. 1-4
Author(s):  
Joseph G. Haubrich
Keyword(s):  
Interest Rates ◽  
Risk Premium ◽  
New Method ◽  
Inflation Expectations ◽  
Real Interest Rates ◽  
Inflation Risk ◽  
New Approach ◽  
Expected Inflation ◽  
Inflation Risk Premium

This Economic Commentary explains a relatively new method of uncovering inflation expectations, real interest rates, and an inflation-risk premium. It provides estimates of expected inflation from one month to 30 years, an estimate of the inflation-risk premium, and a measure of real interest rates, particularly a short (one-month) rate, which is not readily available from the TIPS market. Calculations using the method suggest that longer-term inflation expectations remain near historic lows. Furthermore, the inflation-risk premium is also low, which in the model means that inflation is not expected to deviate far from expectations.

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