515-40-2Relevant articles and documents
Long sought synthesis of quaternary phosphonium salts from phosphine oxides: Inverse reactivity approach
Vetter, Anna C.,Nikitin, Kirill,Gilheany, Declan G.
supporting information, p. 5843 - 5846 (2018/06/13)
Quaternary phosphonium salts (QPS), a key class of organophosphorus compounds, have previously only been available by routes involving nucleophilic phosphorus. We report the realisation of the opposite approach to QPS utilising phosphine oxides as the electrophilic partner and Grignard reagents as nucleophiles. The process is enabled through the crucial intermediacy of the derived halophosphonium salts. The route does not suffer from the slow kinetics and limited availability of many parent phosphines and a broad range of QPS were prepared in excellent yields.
Oxidative C-C bond formation reactivity of organometallic Ni(II), Ni(III), and Ni(IV) complexes
Watson, Michael B.,Rath, Nigam P.,Mirica, Liviu M.
, p. 35 - 38 (2017/05/16)
The use of the tridentate ligand 1,4,7-trimethyl-1,4,7-triazacyclononane (Me3tacn) and the cyclic alkyl/aryl C-donor ligand-CH2CMe2-o-C6H4-(cycloneophyl) allows for the synthesis of isolable organometallic NiII, NiIII, and NiIV complexes. Surprisingly, the fivecoordinate NiIII complex is stable both in solution and the solid state, and exhibits limited C-C bond formation reactivity. Oxidation by one electron of this NiIII species generates a six-coordinate NiIV complex, with an acetonitrile molecule bound to Ni. Interestingly, illumination of the NiIV complex with blue LEDs results in rapid formation of the cyclic C-C product at room temperature. This reactivity has important implications for the recently developed dual Ni/photoredox catalytic systems proposed to involve high-valent organometallic Ni intermediates. Additional reactivity studies show the corresponding NiII species undergoes oxidative addition with alkyl halides, as well as rapid oxidation by O2, to generate detectable NiIII and/or NiIV intermediates and followed by C-C bond formation.
Regio-selective synthesis of key intermediates of fexofenadine
Kumar, Anil,Bhashkar, Bhuwan,Kumar, Harish,Singh, Gurpreet
, p. 2285 - 2287 (2015/12/19)
The present work is focused on improved process of preparation of fexofenadine which is achieved by regio-selective synthesis of intermediate; 1-oxoalkoxy-2-methyl-2-[4-(4-chloro-1-oxobutyl)phenyl]propane. The said intermediate is prepared in good yields and with greater purity wherein the synthesis of side products like 1-oxoalkoxy-2-methyl-2-[3-(4-chloro-1-oxobutyl)phenyl]propane (metaisomer) is reduced to a great amount. The intermediate, 1-oxoalkoxy-2-methyl-2-[4-(4-chloro-1-oxobutyl)phenyl]propane (para-isomer) where, alkyl group is selected from C2-5 carbon chain, is synthesized through preparation of 1-chloro-2-methyl-2-phenylpropane which upon reaction with potassium salt of aliphatic carboxylic acid followed by Friedel-Crafts acylation with 4-chlorobutyrylchloride results into desired intermediate, 1-oxoalkoxy-2-methyl-2-[4-(4-chloro-1-oxobutyl)phenyl]propane and a side impurity, 1-oxoalkoxy-2-methyl-2-[3-(4-chloro-1-oxobutyl)phenyl]propane (meta-isomer) in the ratio of 1:0.09-0.15. The above said mixture can be directly used for the synthesis of fexofenadine and has an advantage of eliminating the purification process at intermediate stage and use of less volume of expensive solvents.
