Visible-Light-Mediated, Organophotocatalytic C-H Thiocyanation of Pyrazolo[1,5-]pyrimidines.

Herein, we report a metal-free, organophotoredox-catalyzed sustainable C-H thiocyanation of a biologically active class of N-heterocycles, pyrazolo[1,5-]pyrimidines, with potassium thiocyanate (KSCN) using 9-mesityl-10-methylacridinium perchlorate as the photocatalyst (PC) and molecular oxygen as the terminal oxidant under blue-light-emitting diode irradiation at room temperature. The developed catalytic protocol features mild reaction conditions, a broad substrate scope, a high yield of products, and a straightforward scalability. Mechanistic studies revealed a radical pathway involving reductive quenching of the PC by KSCN.

HFIP-Mediated, Highly Chemo-, Regio-, and Stereoselective Hydrofunctionalizations of Ynamides: Access to Stereodefined Alkenes Bearing Drugs and Natural Products.

We disclose a sustainable and versatile synthetic strategy for the highly chemo-, regio-, and stereoselective hydrofunctionalizations of ynamides, through its activation by a solvent, HFIP, to access a wide variety of stereodefined ketene ,, ,, ,, and , acetals in high yield at room temperature. The reaction proceeded through the formation of the reactive keteniminium ion intermediate, formed via protonation at the β-carbon of ynamide by HFIP, followed by an attack of a nucleophile (-addition) at the α-carbon. When ynamides are treated with only HFIP at room temperature, the HFIP addition products of ynamides are formed in a 100% atom-economic fashion; however, in the presence of a stronger -/-/-/-based nucleophile, the corresponding -hydroheterofunctionalized products are formed.

Solvent-Controlled, Atom-Economic, and Highly Regio- and Stereoselective Halo-Chalcogenations of Ynamides: Green Synthesis of Stereodefined Tetrasubstituted Alkenes Bearing Four Different Functional Groups.

The synthesis of stereodefined tetrasubstituted alkenes bearing four different functional groups is challenging. Herein, we disclose a 100% atom-economic and highly regio- and stereoselective halo-chalcogenations, in particular, chlorosulfenylation, bromosulfenylation, chloroselenation, and bromoselenation, of ynamides in toluene at room temperature under an aerobic atmosphere for the synthesis of a wide variety of stereodefined tetrasubstituted alkenes bearing four different functional groups in excellent yields. Notably, all the reactions are highly efficient and furnished the desired products in excellent yield (average yield >96%) and stereoselectivity (/ = 90:10 to >99:1) within a short time (15-30 min).

Biomimetic learning of hand gestures in a humanoid robot.

Hand gestures are a natural and intuitive form of communication, and integrating this communication method into robotic systems presents significant potential to improve human-robot collaboration. Recent advances in motor neuroscience have focused on replicating human hand movements from synergies also known as movement primitives. Synergies, fundamental building blocks of movement, serve as a potential strategy adapted by the central nervous system to generate and control movements.

Assessment of universal thermal climate index (UTCI) using the WRF-UCM model over a metropolitan city in India.

Rapid urbanization increases urban air temperature, considerably affecting health, comfort, and the quality of life in urban spaces. The accurate assessment of outdoor thermal comfort is crucial for urban health. In the present study, a high-resolution mesoscale model coupled with a layer Urban Canopy Model (WRF-UCM) is implemented over the city of Hyderabad (17.