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Abstract:The isocoumarins are naturally occurring lactones that constitute an important class of natural products exhibiting an array of biological activities. A wide variety of these lactones have been isolated from natural sources and, due to their remarkable bioactivities and structural diversity, great attention has been focused on their synthesis. This review article focuses on their structural diversity, biological applications, and commonly used synthetic modes.

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Due to vast technology advancement in communication System, it has been possible to use unmanned aerial vehicle (UAV) that can fly independently and worked remotely without carrying any human personnel. UAV provides new methods for communication in military and civilian application. They have small operating and installation cost. They provide flexible way for communication. Unmanned aerial vehicle can be used as Wireless base station in cellular system providing an alternative communication mechanism for cellular communication in any disaster or emergency situation when existing terrestrial network goes down. However besides these several advantages UAVs has many Unique design challenges for both indoor and outdoor users. Energy limitation is one of the major challenges as each UAV has limited battery source so due to limited battery time completing the task in minimum Hover time is another challenge. Another major challenge is Optimal UAVs placement in such a way that Sum data rate of all the users is maximized. this paper investigate the problem of Optimal UAVs placement and minimum transmit power through which better signal to noise ratio is achieved for indoor users, first proved our problem is mixed integer non-linear problem and our objective function is convex and use Genetic algorithm and Nomad to solve our problem, Through Numerical result conclude that optimal placement of UAVs is achieved with minimum path loss and minimum transmit power required to cover indoor user.