- ION PAIRS IN TRIFLUOROACETOLYSIS OF 2-ARYLETHYL ARENESULFONATES
-
The behaviour of ion pairs in the trifluoroacetolysis of 2-arylethyl arenesulfonates was studied by means of tracer techniques with deuterium and oxygen-18
- Yukawa, Yasuhide,Morisaki, Hisao,Tsuji, Kiyoshi,Kim, Seung-Geon,Ando, Takashi
-
-
Read Online
- Synthesis and evaluation of the antioxidant activity of lipophilic phenethyl trifluoroacetate esters by in vitro ABTS, DPPH and in cell-culture DCF assays
-
Polyphenols are natural compounds showing a variety of health-promoting effects. Unfortunately, due to low lipid solubility, their applications in the pharmaceutical, food, and cosmetic industries are limited. With the aim of obtaining novel lipophilic derivatives, the present study reports the synthesis of a series of phenethyl trifluoroacetate esters containing up to two hydroxyl groups in the aromatic ring. Experimental logP values confirmed a greater lipophilicity of the novel compounds compared to the parent compounds. The radical scavenging capacity of all phenethyl trifluoroacetate esters was evaluated by in vitro assays (ABTS, DPPH) and in cultured cells (L6 myoblasts and THP-1 leukemic monocytes) using 2,7-dichlorodihydrofluorescein diacetate. These data revealed that the esters showed a good antioxidant effect that was strictly dependent on the grade of hydroxylation of the phenyl ring. The lack of toxicity, evaluated by the MTT assay and proliferation curves, makes these trifluoroacetates attractive derivatives for pharmaceutical, food, and cosmetic applications.
- Bernini, Roberta,Barontini, Maurizio,Cis, Valentina,Carastro, Isabella,Tofani, Daniela,Chiodo, Rosa Anna,Lupattelli, Paolo,Incerpi, Sandra
-
-
- Unprecedented iron-catalyzed ester hydrogenation. Mild, selective, and efficient hydrogenation of trifluoroacetic esters to alcohols catalyzed by an iron pincer complex
-
The synthetically important, environmentally benign hydrogenation of esters to alcohols has been accomplished in recent years only with precious-metal-based catalysts. Here we present the first iron-catalyzed hydrogenation of esters to the corresponding alcohols, proceeding selectively and efficiently in the presence of an iron pincer catalyst under remarkably mild conditions. The replacement of precious-metal catalysts by an iron complex was accomplished for the synthetically important, environmentally benign hydrogenation of esters to alcohols under mild conditions. The iron pincer complex (see scheme) selectively and efficiently catalyzes the hydrogenation of trifluoroacetates under remarkably mild conditions (5-25 bar and 40 °C).
- Zell, Thomas,Ben-David, Yehoshoa,Milstein, David
-
supporting information
p. 4685 - 4689
(2014/05/20)
-
- Nucleophilic acyl substitutions of anhydrides with protic nucleophiles catalyzed by amphoteric, oxomolybdenum species
-
(Chemical Equation Presented) Among six different group VIb oxometallic species examined, dioxomolybdenum dichloride and oxomolybdenum tetrachloride were the most efficient catalysts to facilitate nucleophilic acyl substitution (NAS) of anhydrides with a myriad array of alcohols, amines, and thiols in high yields and high chemoselectivity. In contrast to the well-recognized redox chemical behaviors associated with oxomolybdenum(VI) species, the catalytic NAS was unprecedented and tolerates virtually all kinds of functional groups. By using benzoic anhydride as a mediator for in situ generation of an incipient mixed anhydride-MoO2Cl2 adduct with a given functional alkanoic acid, one can achieve oleate, dipeptide, diphenylmethyl, N-Fmoc-α-amino, pyruvic, and tert-butylthio ester, N-tert-butylamide, and trityl methacrylate syntheses with appropriate protic nucleophiles. The amphoteric character of the Mo=O unit in oxomolybdenum chlorides was found to be responsible for the catalytic NAS profile as supported by a control NAS reaction of using an authentic adduct-MoOCl2(O2-CBu t)2 between pivalic anhydride and MoO2Cl 2 as the catalyst.
- Chen, Chien-Tien,Kuo, Jen-Huang,Pawar, Vijay D.,Munot, Yogesh S.,Weng, Shieu-Shien,Ku, Cheng-Hsiu,Liu, Cheng-Yuan
-
p. 1188 - 1197
(2007/10/03)
-
- Catalytic nucleophilic acyl substitution of anhydrides by amphoteric vanadyl triflate
-
Figure presented Among four vanadyl species examined, vanadyl triflate was the most efficient catalyst to facilitate nucleophilic acyl substitution of anhydrides with a myriad array of alcohols, amines, and thiols in high yields and high chemoselectivity. By using mixed-anhydride technique, one can achieve oleate and peptide syntheses. In marked contrast to common metal Inflates, the amphoteric character of the V=O unit in vanadyl species was proven to be responsible for the catalytic profile in this process.
- Chen, Chien-Tien,Chang, I-Hsin,Lin, Jin-Sheng,Liu, Chin-Jing,Chou, Y-Chen,Kuo, Jen-Huang,Li, Chun-Hsin,Barhate,Hon, Sang-Wen,Li, Tai-Wei,Chao, Shi-Deh,Liu, Chia-Cheng,Li, Ying-Chieh
-
p. 3729 - 3732
(2007/10/03)
-
- TRIETHYL PHOSPHITE IN ORGANIC SYNTHESIS. A FACILE, ONE-POT CONVERSION OF ALCOHOLS INTO AMINES
-
General protocols for converting primary, secondary, and tertiary alcohols into the corresponding primary amines are presented.
- Zwierzak, Andrzej
-
-