Darjeeling Government College

Rhododendron pendulum Hook.f, a new record belonging to the family Ericaceae series Edgeworthii found in Singalila National Park, Darjeeling, West Bengal, India. The description includes detailed morphology, photographs, GPS location, and sketches. This significant record enriches the flora of West Bengal and increases the number of Rhododendron taxa in the Darjeeling Himalaya to 23. The Sikkim Botanical Survey of India authenticated the specimen (Accession no. 0313). As the species is rare in the park, conservation strategies have also been implemented.

Two diorganotin(IV) complexes of the general formula[R2Sn{Ph(O)C=CH-C(Me)=N-C6H3(2-O)(4-NO2)}] [R2Sn (HNPP)] (R = Ph, 1a; R = Me, 1b) have been synthesized from the corresponding diorganotin(IV) dichlorides and the ligand, 3-((2-hydroxy-4-nitrophenyl)imino)-1-phenylbutan-1-one, H2HNPP (1) in methanol at room temperature in presence of triethylamine. Both compounds have been characterized by elemental analyses, IR and 1H, 13C, 119Sn NMR spectra. The structures of the free ligand and the complexes have been confirmed by single crystal X-ray diffraction. There are two independent molecules in the crystal structure of the ligand 1 and the O-bound proton in imino-en-ol form (II) of the ligand is not transferred to the imine nitrogen as compared to the ligand, 3-(2-hydroxyphenylimino)-1-phenylbutan-1-one (H2HPP) in which O-bound proton is transferred to the imine nitrogen. The X-ray structure of the ligand, H2HNPP (1) shows that it exists exclusively in keto form in solid state but it exists as enol form in solution as evident from solution state NMR spectrum. It reacts with diorganotin(IV) dichlorides in solution as enol form. In both 1a and 1b, the central tin atom adopts distorted trigonal-bipyramidal coordination geometry. The dimethyltin(IV) compound (1b) derived from H2HNPP (1) is not dimeric whereas dimethyltin(IV) compound derived from H2HPP was dimeric. This may be due to presence of-NO2 group in 1, which makes phenolic-O less basic. The delta(119Sn) values for the complexes 1a and 1b are-301.7 and-124.1 ppm, respectively, thus indicating penta-coordinated Sn centres in solution.

Exploring the emergence of spatio-temporal patterns due to nonlinearities in gene expression is a relatively new development. In this work, we explore the effect of resource constraint on gene regulatory motif from both equilibrium and spatio-temporal standpoint, taking into consideration the degradation class of resource, protease. We have demonstrated that protease-tagged degradation can cause an emergent bistability to form in the system in a steady-state scenario. Instead of a graded linear response in protein synthesis, two Saddle-node bifurcations caused by protease competition provide a switch-like response with hysteresis, where two drastically differing protein concentrations can coexist. We next turn our attention to spatio-temporal analysis: we extend our study for a two-dimensional sheet of cells with diffusible protein molecules and report the stationary patterns.To investigate the reasons behind these non-homogeneous stationary patterns, we investigate the traveling wave solution and observe that a stationary pattern is formed by the traveling wave solution. Considering that proteases play a major role in the regulation and expression of genes in a variety of diseased scenarios, the repercussions of this spatial patterning caused by protease competition can be extensive in gene regulatory systems.

Cross-coupling reactions are the most reliable techniques in organic synthesis for constructing various C-C and C-heteroatom bonds, enabling the formation of complex molecular scaffolds with significant chemical and physical properties and their diverse applications. More specifically, defunctionalized cross-coupling strategies have attracted significant research interest due to their inherent advantages, including a broader substrate scope, elimination of prior pre-functionalization steps, and improved product yields compared to traditional cross-coupling methods, which often suffer from several limitations. The limitations of traditional cross-coupling reactions have been addressed through the development of sustainable pathways such as metal-free, photocatalytic, microwave-assisted, and electrochemical methodologies, which have been well documented in the literature. Therefore, a comprehensive perspective review on recent advancements in the synthetic applications of various defunctionalized cross-coupling reactions is in high demand, as it would stimulate new ideas and fresh thinking among emerging researchers. Hence, in the present article, we have summarized the recent advancements in cross-coupling reactions, with particular emphasis on the latest electrochemical strategies developed and explored over the past decade, along with their future prospects. Specifically, we have discussed electrochemical defunctionalized cross-coupling strategies including decarboxylative, deaminative, decyanative, dehalogenative, deoxygenative, and decarbonylative coupling reactions, which represent more sustainable alternatives for the formation of C-C, C-N, C-O, and C-X bonds in the current synthetic landscape. Furthermore, brief mechanistic insights, representative examples, critical discussions, and future perspectives are provided. This article is expected to serve as a valuable resource for young researchers and scholars, fostering innovative ideas and opening new avenues in synthetic organic chemistry research.