- Efficient synthesis of vitamin e intermediate by lipase-catalyzed regioselective transesterification
-
Trimethylhydroquinone-1-monoacetate (TMHQ-1-MA) is a valuable synthetic intermediate for vitamin E acetate. Immobilized Lipozyme RM IM from Mucor miehei was shown to be the best biocatalyst for the production of TMHQ-1-MA through regioselective transesterification between trimethylhydroquinone diacetate (TMHQ-DA) and alcohol. The effects of lipase-catalyzed reaction conditions including solvent, acyl receptor, substrate mole ratio, reaction temperature and agitation speed were investigated. The optimum conditions for Lipozyme RM IM catalyzed regioselective transesterification were achieved at a substrate mole ratio of 1:1, an agitation of 200 rpm at 50 °C in MTBE/n-hexane (3:7). Under the above conditions, Lipozyme RM IM exhibited high substrate tolerance (substrate concentrations of 1.06 M). Recycling experiments demonstrated that Lipozyme RM IM was quite steady under the reaction conditions. The analysis of kinetic experiment showed that the enzymatic reaction obeys the Ping-Pong bi-bi mechanism with n-butanol inhibition.
- Wei, Chun,Fu, Xian-Feng,Wang, Zhao,Yu, Xin-Jun,Zhang, Yin-Jun,Zheng, Jian-Yong
-
-
- SUBSTITUTED PHENOLS AND THIOPHENOLS USEFUL AS ANTIOXIDANT AGENTS
-
The present invention provides compounds of formula (1), wherein X is selected from the group consisting (a), (b), (c), (d), (e) or (f); Y is thio, oxy or a methylene group; Z is hydrogen or -C(O)-(CH2)m-Q, wherein Q is hydrogen or -COOH and m is an integer 1, 2, 3 or 4; R1 is C1-C6 alkyl; and R2, R3 and R4 are each independently hydrogen or C1-C6 alkyl; or a stereoisomer thereof; useful for the treatment of atherosclerosis and chronic inflammatory disorders; for inhibiting cytokine-induced expression of VCAM-1 and/or ICAM-1; for inhibiting the peroxidation of LDL lipid; for lowering plasma cholesterol; and as anti-oxidant chemical additives useful for preventing oxidative deterioration in organic materials.
- -
-
-
- Process for producing chromans
-
A process for producing chromans, comprising reacting a phenol, a formaldehyde and an alcohol in the presence of a secondary amine and an acid, to generate an alkoxymethylphenol compound with the ortho position to the phenolic hydroxyl group substituted with an alkoxymethyl group, and reacting the alkoxymethylphenol compound with an unsaturated compound having a carbon--carbon double bond.
- -
-
-
- Substituted phenols and thiophenols useful as antioxidant agents
-
The present invention provides compounds of the formula STR1 wherein X is selected from the group consisting of STR2 Y is thio, oxy or a methylene group; Z is hydrogen or --C(O)--(CH 2) m --Q wherein Q is hydrogen or --COOH and m is an integer 1, 2, 3 or 4; PA1 R 1 is C 1 -C 6 alkyl; and PA1 R 2, R 3 and R 4 are each independently hydrogen or C 1 -C 6 alkyl; PAL or a stereoisomer thereof; useful for the treatment of atherosclerosis and chronic inflammatory disorders; for inhibiting cytokine-induced expression of VCAM-1 and/or ICAM-1; for inhibiting the peroxidation of LDL lipid; for lowering plasma cholesterol; and as anti-oxidant chemical additives useful for preventing oxidative deterioration in organic materials.
- -
-
-
- Alkyl-4-silyl-phenols and esters thereof as antiatherosclerotic agents
-
This invention relates to compounds of the formula STR1 wherein R1 and R6 are each independently C1 -C6 alkyl; R2, R3 and R4 are each independently hydrogen or C1 -C6 alkyl; R is hydrogen or --C(O)--(CH2)m --Q wherein Q is hydrogen or --COOH and m is an integer 1, 2, 3 or 4; Z is a thio, oxy or methylene group; A is a C1 -C4 alkylene group; R5 and R7 are each independently a C1 -C6 alkyl or --(CH2)n --(Ar) wherein n is an integer 0, 1, 2 or 3; and Ar is phenyl or naphthyl unsubstituted or substituted with one to three substituents selected from the group consisting of hydroxy, methoxy, ethoxy, halogen, trifluoromethyl, C1 -C6 alkyl, or --NR8 R9, wherein R8 and R9 are each independently hydrogen or C1 -C6 alkyl; with the proviso that when R2 and at least one of R5 or R7 is C1 -C6 alkyl, and Ar is not substituted with trifluoromethyl or --NR8 R9, then R is --C(O)--(CH2)m --Q; or a pharmaceutically acceptable salt thereof; useful for the treatment of atherosclerosis and chronic inflammatory disorders; for inhibiting cytokine-induced expression of VCAM-1 and/or ICAM-1; for inhibiting the peroxidation of LDL lipid; for lowering plasma cholesterol; and as antioxidant chemical additives useful for preventing oxidative deterioration in organic materials.
- -
-
-
- REACTION OF 1,2,4-TRIMETHYLBENZENE WITH PERACETIC ACID
-
The oxidation of 1,2,4-trimethylbenzene with peracetic acid leads to the formation of trimethylphenols and hydroquinones, which undergo transformations to the corresponding benzoquinones and products from oxidative cleavage of the ring.The controlling stage of the process is the electrophilic hydroxylation of 1,2,4-trimethylbenzene.
- Kharchuk, V. G.,Kolenko, I. P.,Petrov, L. A.,Gus'kova, L. M.
-
p. 2071 - 2078
(2007/10/02)
-
