Chemistry is an experimental science, and the best way to enjoy it and learn about it is performing experiments.Introducing a new discovery about 1806-29-7, Name is 2,2-Biphenol, Application In Synthesis of 2,2-Biphenol.
Stereoselective Formation of beta-O-4 Structures Mimicking Softwood Lignin Biosynthesis: Effects of Solvent and the Structures of Quinone Methide Lignin Models
p-Quinone methide (QM) is formed as an intermediate during lignin biosynthesis. The aromatization of the QM by the attack of a nucleophile at the alpha-position of its side chain generates a phenolic hydroxy group in a growing polymer and creates stereoisomeric forms in the side chain. A series of beta-O-4-aryl ether QMs was reacted with water at 25 C to replicate the formation of p-hydroxyphenyl (H) and guaiacyl (G) beta-O-4 structures in plant cell walls. Water addition occurred in 3-methoxy-substituted QMs (G-type QMs) with half-lives (t1/2) between 13 and 15 min, at pH 7, in 50% water solution (dioxane-water, 1:1). The rate increased as the water concentration increased to 99% (t1/2, 1.2-1.4 min). Similar solvent effects were observed for more reactive nonsubstituted QMs (H-type QMs with t1/2 of <1 min). Consequently, t1/2 of the H-type QMs was shorter than that of the G-type QMs under every solvent condition. Upon increasing the water concentration, the variation in the erythro/threo ratios of the four dimeric beta-O-4 products increased. Interestingly, the effect of pH on the stereopreference, which was observed in 50% water solution, was small and became imperceptible as the water concentration increased to 99%, suggesting that the effect of the solvent, as well as the effect of the pH, plays an important role in understanding the reaction conditions in cell walls during lignin biosynthesis. The threo isomer was preferentially formed in the four dimeric beta-O-4 structures, which is inconsistent with the structural features of compression wood lignin rich in H-units. However, the erythro-selective formation was attained in an H-type QM at every pH studied (pH 3.5-7) by introducing a biphenyl structure into the beta-etherified ring moiety. Balanced chemical reaction does not necessarily reveal either the individual elementary reactions by which a reaction occurs or its rate law.Application In Synthesis of 2,2-Biphenol. In my other articles, you can also check out more blogs about 1806-29-7
Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare