517 research outputs found
An iterative approach to higher polyquinanes
A simple cyclopentane annulation strategy has been developed using inexpensive reagents. Starting from the readily available bicyclo[3.3.0]octane system several polyquinanes were prepared by iterative annulation procedure and herein we report a short and a convenient route to a new C20-hexaquinane system
Synthetic approach to linearly annulated tetralin-based constrained α-amino acid derivatives via Rongalite
Tetralin-based α-amino acid derivatives were assembled through the application of Diels-Alder reaction as a key step. Here, Rongalite has been used to generate the key o-xylylene intermediate
Synthesis of cage heterocycles containing tetrahydrofuran and pyran ring system via Grignard addition and ring-closing metathesis
75-84Several cage compounds containing tetrahydrofuran and pyran rings have been reported by using the Grignard addition and ring-closing metathesis as key steps. Cage hemiketal derivatives have been generated due to the proximity of two carbonyl groups in cage dione. These cage heterocycles have been derived from readily available starting materials such as 1,4-hydroquinone and dicyclopentadiene
Synthesis of cage heterocycles containing tetrahydrofuran and pyran ring systemvia Grignard addition and ring-closing metathesis
Several cage compounds containing tetrahydrofuran and pyran rings have been reported by using the Grignard additionand ring-closing metathesis as key steps. Cage hemiketal derivatives have been generated due to the proximity of twocarbonyl groups in cage dione. These cage heterocycles have been derived from readily available starting materials such as1,4-hydroquinone and dicyclopentadiene
GSM BASED INTELLIGENT WIRELESS MOBILE PATIENT MONITORING SYSTEM USING ZIGBEE COMMUNICATION
Miniaturization of biomedical sensors helped the fast development and popularization of information processing and wireless data transmission technology, the research of wireless Medical Monitoring System has became a hot topic. By utilizing the wireless technique to transmit information between medical sensor and monitoring control center, the free space of patients is enlarged, and the efficiency of the modern management of hospitals is improved. Besides, the problem of the lack of unremitted real-time care for every patient, which is caused by the shortage of health care members, is also solved. Therefore, the portable wireless medical monitoring products will become popular in the future market. This paper deals with one of such Medical Application of Wireless Networks
Quantifying The Role of Vegetation in Slope Stability
Soil erosion and landslides are the two great concerns to the land managers in the world. The presence of root system in the soil plays good role in increasing the stability of the slope .The hydrological and geo mechanical effects due to the vegetation increase the stability of the slope. The hydrological effect due to the vegetation is related to the soil suction regime and the geo mechanical effect is related to the reinforcement provided by the root network in soil. In this project, the mechanical effect of vegetation on the slope stability is calculated. The finite element package PLAXIS 3D version 2013 is used for stability analysis of the slope. This study also highlights the use of reliability analysis in slope stability. Reliability analysis is performed on the slope which is covered with vegetation. The limit state function is developed by using the linear response surface model. The two level full factorial design is used for the design of experiments (DoE). The reliability index (ß) is calculated by using the first order reliability method. The standard USACE chart is used to calculate the probability of failure (Pf) of the slop
A protection PWS system UPS to sum up profiles as per client security prerequisites
Personalized web search has demonstrated its effectiveness in improving the quality of various search services on the Internet. However, evidences show that users’ reluctance to disclose their private information during search has become a major barrier for the wide proliferation of PWS. We study privacy protection in PWS applications that model user preferences as hierarchical user profiles. We propose a PWS framework called UPS that can adaptively generalize profiles by queries while respecting user-specified privacy requirements. Our runtime generalization aims at striking a balance between two predictive metrics that evaluate the utility of personalization and the privacy risk of exposing the generalized profile. We present two greedy algorithms, namely GreedyDP and GreedyIL, for runtime generalization. We also provide an online prediction mechanism for deciding whether personalizing a query is beneficial. Extensive experiments demonstrate the effectiveness of our framework. The experimental results also reveal that GreedyIL significantly outperforms GreedyDP in terms of efficiency
Synthetic approach to oxa-triquinanes via olefin metathesis as a key step
Earlier, a simple synthetic approach to cis, syn, cis-triquinanes and propellanes from exo-nadic anhydride through metathesis approach had been demonstrated. In the present work is discussed a distinct course of observations when this methodology has been extended to oxygenated exo-nadic anhydride derivatives and the importance of stereochemistry and the role of hetero atom in the outcome of olefin metathesis has been demonstrated
Synthesis of spiro-annulated cyclobutane derivatives through ketene [2+2] cycloaddition and ring-rearrangement metathesis
Herein is reported a concise synthesis of spiro-annulated cyclobutane tetracyclic and pentacyclic derivatives by ketene addition, and ring-rearrangement metathesis (RRM) as key steps, starting with commercially available norbornadiene and dicyclopentadiene. The tetracyclic spiro-derivative contains a [5/5/4] core unit, which is the key building block to angular triquinanes synthesis. Whereas, the pentacyclic spiro-derivative contains a basic core skeleton of presilphiperfolanes, and other sesquiterpenoids
Synthetic approach to oxa-triquinanes via olefin metathesis as a key step
1868-1874Earlier, a simple synthetic approach to cis, syn, cis-triquinanes and propellanes from exo-nadic anhydride through metathesis approach had been demonstrated. In the present work is discussed a distinct course of observations when this methodology has been extended to oxygenated exo-nadic anhydride derivatives and the importance of stereochemistry and the role of hetero atom in the outcome of olefin metathesis has been demonstrated
- …