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1.
Ammonium acetate was found to catalyze efficiently the selective deprotection of aromatic acetates in the presence of various sensitive functionalities in aqueous methanol under neutral conditions at room temperature to yield the corresponding phenols in excellent yields. The method has been utilized for deprotection of acetates of several naturally occurring bioactive phenolic compounds and for preparation of venkatasin, a natural coumarino-lignan, from the anticancer compound cleomiscosin A. 相似文献
2.
Raymond J. Huntley Mahender GurramJoel R. Walker David M. JenkinsEmmanuel J. Robé Feryan Ahmed 《Tetrahedron letters》2014
A new synthetic method has been developed for the synthesis of 2,4,5-substituted isoindolinones by means of intramolecular inverse-electron demand Diels–Alder cycloaddition reactions of substituted pyridazines. By taking advantage of the inherent reactivity of an intermediate chloropyridazine, a diverse set of analogues were prepared from common reagents and intermediates. 相似文献
3.
Mahender Reddy Marri Swamy PerakaArun Kumar Macharla Naresh MamedaSrujana Kodumuri Narender Nama 《Tetrahedron letters》2014
A new and efficient protocol is described for the one-pot synthesis of benzimidazoles from a variety of aryl alcohols and 1,2-diaminoarenes. The yields were ranging from moderate to excellent. Moreover, the present method is utilizing alcohols instead of aldehydes and the reactions are carried out under solvent- and catalyst-free conditions, offering an environmentally benign process. 相似文献
4.
Sanjiv Arora Rajeev Bagoria Mahender Kumar 《Journal of Thermal Analysis and Calorimetry》2010,102(1):375-381
Alpha-tocopherol (vitamin E) is the most widely used antioxidant for edible oils. The present investigation presents its effect
on the thermal degradation behavior of edible oils (sunflower, soybean, and their blend) through the use of dynamic thermogravimetry.
The study is based on the comparison of activation energies of decomposition process which were subsequently calculated using
preferred and reliable multiple-heating rate methods viz. Kissinger, Friedman, Ozawa–Flynn–Wall, and Coats–Redfern (modified).
It is concluded that the role of alpha-tocopherol as antioxidant at higher temperature is nearly accomplished. 相似文献
5.
K. Mahender ReddyJ. Shashidhar Gurava Reddy PottireddygariSubhash Ghosh 《Tetrahedron letters》2011,52(45):5987-5991
This Letter describes the synthetic studies of stereocalpin A and its C5-epimer. After various cyclization attempts, successful macrolactamization at 9-10 position was tried inorder to obtain stereocalpin A and its C5-epimer, which were accompanied by complete racemization and resulted in the synthesis of 11-epi- and 5,11-diepi-stereocalpin A. Highly functionalized octanoic acid motif of the depsipeptide was constructed by applying Paterson’s aldol methodology, owing to its diversity in synthesizing various analogs of aliphatic acid. 相似文献
6.
Mahender Singh 《Mathematica Slovaca》2011,61(4):653-656
We show that the inverse limit and the orbit map commute for actions of compact groups on compact Hausdorff spaces. 相似文献
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8.
We consider a polling model in which a number of queues are served, in cyclic order, by a single server. Each queue has its own distinct Poisson arrival stream, service time, and switchover time (the server's travel time from that queue to the next) distribution. A setup time is incurred if the polled queue has one or more customers present. This is the polling model with State-Dependent service (the SD model). The SD model is inherently complex; hence, it has often been approximated by the much simpler model with State-Independent service (the SI model) in which the server always sets up for a service at the polled queue, regardless of whether it has customers or not. We provide an exact analysis of the SD model and obtain the probability generating function of the joint queue length distribution at a polling epoch, from which the moments of the waiting times at the various queues are obtained. A number of numerical examples are presented, to reveal conditions under which the SD model could perform worse than the corresponding SI model or, alternately, conditions under which the SD model performs better than a corresponding model in which all setup times are zero. We also present expressions for a variant of the SD model, namely, the SD model with a patient server. 相似文献
9.
Dewal MB Xu Y Yang J Mohammed F Smith MD Shimizu LS 《Chemical communications (Cambridge, England)》2008,(33):3909-3911
Changing an ether to a ketone within the framework of a bis-urea macrocycle has little effect on the supramolecular assembly of this building block into porous crystals but introduces a triplet sensitizer into the framework that dramatically alters the photochemical reactions of included guests. 相似文献
10.
Chevella Durgaiah Mameda Naresh Macharla Arun Kumar Peraka Swamy Marri Mahender Reddy Kodumuri Srujana 《合成通讯》2016,46(13):1133-1144
A simple, efficient, and environmentally benign protocol for the synthesis of vicinal iodohydrins and iodoesters from olefins using NH4I and Oxone in CH3CN/H2O (1:1) and dimethylformamide (DMF) / dimethylacetamide (DMA), respectively, without employing a catalyst at room temperature is described. Regio- and stereoselective iodohydroxylation and iodoesterification of various olefins with anti fashion, following Markonikov’s rule, was achieved and the corresponding products were obtained in good to excellent yields. In addition, 1,2-disubstituted olefins afforded excellent diastereoselectivity. 相似文献