Practical Approach for Clean Preparation of Z-β-Thiocyanate Alkenyl Esters

Abstract

A practical and eco-friendly method for the clean preparation of a variety of Z-β-thiocyanate alkenyl esters via lactic acid-catalyzed multicomponent hydrothiocyanation reaction was established. In the subgram-scale synthesis, Z-β-thiocyanate alkenyl esters were exclusively generated, and the product could be easily isolated in high purity via extraction. In the large-scale synthesis, the pure products could be simply collected through liquid–liquid separation. The eco-friendly lactic acid played a dual function in the transformation, serving as recyclable biomass catalyst and recyclable reaction medium.

Visible-Light-Initiated One-Pot, Three-Component Synthesis of 2-Amino-4H-pyran-3,5-dicarbonitrile Derivatives

“…In the past few years, visible light as clean, safe, nonpolluting, inexpensive, abundant, and sustainable energy source has been utilized for the design of a variety of organic reactions under mild reaction conditions and low-energy irradiation, and remarkable achievements have already been demonstrated. − In a photopromoted organic synthetic chemical reaction, light acts as a reagent to induce conversion of a compound as it is usually carried out by a chemical reagent . Moreover, multicomponent reactions (MCRs) have become a fascinating and powerful synthetic tool in organic synthesis, and medicinal and combinatorial chemistry by the reaction of three or more different starting materials in a one-pot manner for the construction of complex molecular structures with shortened reaction time, increased yield, fewer side products, and simple workup procedures compared with conventional reaction strategies. − At the same time, catalyst-free protocols have become an important strategy because of their simple workup, low cost, reduced contamination, and avoidance of the effects of catalysts on sensitive substrates . These characteristics meet the requirements of green chemistry.…”

Direct cyanation, hydrocyanation, dicyanation and cyanofunctionalization of alkynes

“…Aer treating alkynes 59 with KSCN in the presence of natural lactic acid under ultrasound conditions for 30 min, the expected Z-b-thiocyanate alkenyl esters 60 was formed in excellent yields. 43 Iodine-mediated regio-and stereoselective iodothiocyanation of alkynes was reported by Zeng and Chen in 2018 (Scheme 34). Iodothiocyanation of alkyne 61 with NH 4 SCN in the presence of I 2 as the iodine source and EtOH/H 2 O as the solvent at 80 C under air afforded series of functional b-iodo vinylthiocyanates 62 in good to excellent yields.…”

Visible‐Light‐Promoted Synthesis of Fusesd Imidazoheterocycle by Eosin Y under Metal‐Free and Solvent‐Free Conditions

“…[16] Compared to conventional reaction strategies, multicomponent reactions (MCRs) have emerged as an intriguing and effective synthetic method in organic synthesis, combinatorial chemistry, and medicinal chemistry, involving the one-pot reaction of three or more than three different starting components to construct the complex molecules with reduced reaction time, improved yield, lesser side products, and easy procedure for workup. [17][18][19][20][21][22][23][24][25][26][27][28] Imidazopyrimidines, imidazopyrazines, and imidazopyridines, which are imidazo-fused bicyclic heterocycles, are privileged pharmacophores in the field of organic and medicinal chemistry. These moieties can be used to treat cancer, [29] inflammation, [30] bacterial infection, [31] HIV, [32] cancer-induced osteoporosis, [33] Alzheimer's disease, [34] and diabetes.…”