10.1007/BF00956104
The research investigates the Leuckart reaction for synthesizing sterically hindered aminophenols from carbonyl derivatives of 2,6-di-tert-butylphenol. The key chemicals involved include 3,5-di-tert-butyl-4-hydroxybenzaldehyde, 3,5-di-tert-butyl-4-hydroxyacetophenone, and 3,5-di-tert-butyl-4-hydroxypropiophenone as starting materials. Formamide or ammonium formate is used as the reaction medium, and hydrochloric acid is employed in the acid hydrolysis step to obtain the final amines. Additionally, methylenequinone reacts with ammonia to produce aminophenol derivatives. The study demonstrates that these aminophenols and their analogs can be prepared in high yields through the Leuckart reaction, highlighting the efficiency and potential applications of this synthetic approach.
10.1021/jo060281e
This research investigates the impact of electronic and hydrogen bonding effects on the chain-breaking activity of sulfur-containing phenolic antioxidants. The study aims to understand the influence of sulfur substituents on the O-H bond dissociation enthalpy (BDE) and reactivity towards peroxyl radicals in phenolic antioxidants. The researchers found an inverse correlation between BDE and reactivity, with para-substituted thiyl groups decreasing BDE values to a lesser extent than methoxy groups, while ortho-substituted thiyl groups showed an opposite trend. The study concluded that sulfur-containing phenols exhibit enhanced activity as chain-breaking antioxidants compared to their oxygenated counterparts, but to a lesser extent than methoxy phenols. The research used a variety of phenols, including 2,6-di-tert-butylphenols substituted with thiyl (SR), sulfinyl (SOR), and sulfonyl (SO2R) groups, along with various solvents and reagents such as cumene, styrene, and di-tert-butyl peroxide. The findings suggest that the antioxidant efficacy of phenols para-substituted with XR groups decreases in the order X = O > S > Se, and the intramolecular hydrogen bond of the phenolic OH proton to the adjacent SMe group is weaker than that to an OMe group.
Xn,
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