A polystyrene-supported zinc bromide-ethylenediamine complex was shown to be useful as a recyclable heterogeneous catalyst for the rapid and efficient synthesis of a,b-acetylenic ketones in good-to-excellent yields by cross-coupling of acid chlorides with terminal alkynes. The catalyst is easily prepared, stable, reusable, and efficient under the reaction conditions.
The problem of multicollinearity among predictor variables is a frequent issue in longitudinal data analysis. In this context, this paper proposes a mixed ridge regression model via shrinkage methods to analyze such data. Furthermore, in view of obtaining more efficient estimators, we propose preliminary and Stein-type estimators using prior information for fixedeffects parameters. The model parameters are estimated via the EM algorithm. A simulation study is also presented to assess the performance of the estimators under different estimation methods. An application to the HIV data is also illustrated.
Polystyrene-Supported Zinc Bromide-Ethylenediamine Complex as a Reusable and Highly Efficient Heterogeneous Catalyst for the Synthesis of α,β-AcetylenicKetones. -(KEIVANLOO*, A.; BAKHERAD, M.; BAHRAMIAN, B.; RAHMANI, M.; TAHERI, S. A. N.; Synthesis 2011, 2, 325-329, http://dx.doi.org/10.1055/s-0030-1258365 ; Sch. Chem., Shahrood Univ. Technol., Shahrood, Iran; Eng.) -Mais 21-076
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