Supercooled deep eutectic melt of tetramethylguanidine hydrochloride and sorbitol: An efficient promoter for synthesis of pyrano[3,2-c]chromenes

• Published in: Journal of molecular liquids 2022-12, Vol.367, p.120501, Article 120501
• Main Authors: Ahmadian, Mahsa, Rad-Moghadam, Kurosh, Gholami, Zohreh
• Format: Article
• Language: English
• Subjects: Deep eutectic solvent; Ionic liquid; Pyrano[3,2-c]chromene; Sorbitol; Supercooled liquid
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2022.120501

[Display omitted] •A new natural deep eutectic melt with a wide liquidity window was obtained.•It can exist as a supercooled liquid below its glass transition point at −42 °C.•It has a significant electric conductance and is thermally stable up to 190 °C.•It is an amphipathic solvent, making it easily separable from organic reactions.•It was tested as an efficient promoter in the synthesis of pyrano[3,2-c]chromenes. Glassy viscous liquids were obtained by heating some mixtures of tetramethylguanidine hydrochloride and sorbitol in different molar ratios at temperatures far below the melting points of the two components. The seminatural deep eutectic melt, which was prepared in this way, showed a wide liquid window, as preserves its fluidity even by standing at −60 °C for 2 days and is thermally stable up to 190 °C. It displays a significant electric conductivity and maintains its liquid state at ambient temperature even by dissolving additional amounts of sorbitol and shows an efficient promotion effect on the three-component synthesis of pyrano[3,2-c]chromenes. Interestingly, sorbitol preserves its chemical identity in the melt, as no signals attributable to formation of isosorbid or sorbitan are detected in the NMR spectra of the melt.