Sanjeev Kumar

Abstract: Herein, we report a mild and significant method for the synthesis of oxaspirocyclohexadienones by using a combination of Lewis acid-HFIP mediated [2+3]-annulation of p-quinone methides (p-QMs) and iodonium ylides. The proposed mechanism proceeds through a one-pot sequence of carbonyl activation/cyclopropyl formation/Cloke-Wilson rearrangement to provide a broad range of oxaspirocyclohexadienones in moderate to high yields. Interestingly, the spiro-annulated products were further converted to tetrahydroxanthane derivatives via BF3.OEt2 mediated dienone-phenol rearrangement pathway. Moreover, the spiro-annulated derivatives also showed a moderate anti-tuberculosis activity against Mycobacterium tuberculosis H37Ra ATCC25177.

Adda247's

Adda247's

hello sir how i get free computer training institute for students.

Vishwajit Chavda Harsh D. Patel A. K. Patel Darshna Hirpara N. K. Acharya

School of Health Sciences, Western Sydney University, Campbelltown, NSW 2560, Australia

Artificial Intelligence (AI) is no longer just a futuristic concept; it's a transformative force that is reshaping industries across the globe. For

We are at a pivotal moment where generative AI is set to redefine industries and society globally, much like the internet did for the information age.

In recent times, photonic synthesis and processing of arbitrary microwave waveforms have gained interest due to their high frequency and huge time–bandwidth product. This study reviews methods for producing dual-chirp microwave waveforms, focusing mostly on system topologies based on external modulation techniques, such as cascaded Mach–Zehnder modulator (MZM), dual parallel MZM, and dual polarized MZM. Other photonic approaches, like using semiconductor laser and optical heterodyne detection methods, are also discussed. These techniques are preferable because of high frequency, enhanced time–bandwidth product, greater chirp rate, and many more advantages. Additionally, the difficulties associated with integrating the systems into real-world applications are also addressed.

Fire and flooding accidents onboard ships can only be minimised, never eliminated. The rising trend indicates that we are not on the right side of this balance and some major course corrections may be needed.