Search

A novel synthetic approach to 2,3,6-trisubstituted pyridines, their 4,5-dideuterated derivatives, 4,5- 13 C 2 - and doubly-labeled D 2 - 13 C 2 -pyridines has been developed using catalyst-free [4+2] cycloaddition of 1,2,4-triazines and in situ generated acetylene or labeled acetylene. Calcium carbide and water or deuterium oxide were used for the in situ generation of acetylene and dideuteroacetylene. Calcium carbide- 13 C 2 in the mixture with water or deuterium oxide was applied as 13 C 2 -acetylene and D 2 - 13 C 2 -acetylene source., (© 2023 Wiley-VCH GmbH.)

Recent progress in the leading synthetic applications of acetylene is discussed from the prospect of rapid development and novel opportunities. A diversity of reactions involving the acetylene molecule to carry out vinylation processes, cross-coupling reactions, synthesis of substituted alkynes, preparation of heterocycles and the construction of a number of functionalized molecules with different levels of molecular complexity were recently studied. Of particular importance is the utilization of acetylene in the synthesis of pharmaceutical substances and drugs. The increasing interest in acetylene and its involvement in organic transformations highlights a fascinating renaissance of this simplest alkyne molecule., Competing Interests: The authors declare no conflict of interest.

A novel synthetic methodology for the preparation of 1,3-disubstituted pyrazoles from in situ generated nitrile imines and acetylene is reported. The reactions are performed in a simple two-chamber reactor. One part of the reactor is loaded with hydrazonoyl chloride precursors of active nitrile imine species and a base. The other part is used to generate acetylene from CaC 2 and water. Partitioning of the reactants improves the yields of desired pyrazoles up to 99% and simplifies their isolation to a simple procedure of solvent evaporation. The approach requires no complex equipment and utilizes inexpensive, safe, and easy to handle calcium carbide as a starting material. A model deuterium incorporation is carried out according to the developed methodology, producing a series of novel 4,5-dideuteropyrazoles with excellent deuterium enrichment. Theoretical calculations on reaction mechanism and characterization of possible intermediate structures were performed.

A system of automated control Aspect-2 was developed for automation of gamma-beam therapy on units of the Rokus series. The system consists of the following hardware and software complexes: a complex of preirradiation preparation "Centrator-imitator"; a complex Accord for anatomotopographic data coding; a software complex and a gamma-therapeutic complex Rokus-AM. The Centrator-imitator and Rokus-AM complexes are fitted out with built-in microcomputers with specially developed systemic software. The Rokus-AM complex has automatic punch tape programmed control of 9 degrees of freedom of the gamma-unit and treatment table and ensures 5 modes of irradiation: positional, rotating, rotating-convergent, sectoral rotating-convergent and scanning.