788-17-0Relevant academic research and scientific papers
Rational and predictable chemoselective synthesis of oligoamines via Buchwald-Hartwig amination of (hetero)aryl chlorides employing Mor-Dalphos
Tardiff, Bennett J.,McDonald, Robert,Ferguson, Michael J.,Stradiotto, Mark
experimental part, p. 1056 - 1071 (2012/02/15)
We report a diverse demonstration of synthetically useful chemoselectivity in the synthesis of di-, tri-, and tetraamines (62 examples) by use of Buchwald-Hartwig amination employing a single catalyst system ([Pd(cinnamyl)Cl]2/L1; L1 = N-(2-(di(1-adamantyl)phosphino)phenyl) morpholine, Mor-DalPhos). Competition reactions established the following relative preference of this catalyst system for amine coupling partners: linear primary alkylamines and imines > unhindered electron-rich primary anilines, primary hydrazones, N,N-dialkylhydrazines, and cyclic primary alkylamines > unhindered electron-deficient primary anilines, α-branched acyclic primary alkylamines, hindered electron-rich primary anilines ? cyclic and acyclic secondary dialkylamines, secondary alkyl/aryl and diarylamines, α,α-branched primary alkylamines, and primary amides. The new isomeric ligand N-(4-(di(1-adamantyl)phosphino)phenyl)morpholine (p-Mor-DalPhos, L2) was prepared in 63% yield and was crystallographically characterized; the [Pd(cinnamyl)Cl]2/L2 catalyst system exhibited divergent reactivity. Application of the reactivity trends established for [Pd(cinnamyl)Cl] 2/L1 toward the chemoselective synthesis of di-, tri-, and tetraamines was achieved. Preferential arylation was observed at the primary alkylamine position within 2-(4-aminophenyl)ethylamine with [Pd(cinnamyl)Cl] 2/L1 and 4-chlorotoluene (affording 5a); the alternative regioisomer (5a′) was obtained when using [Pd(cinnamyl)Cl]2/L2. These observations are in keeping with coordination chemistry studies, whereby binding of 2-(4-aminophenyl)ethylamine to the in situ generated [(L1)Pd(p-tolyl)] + fragment occurred via the primary amine moiety, affording the crystallographically characterized adduct [(L1)Pd(p-tolyl)(NH2CH 2CH2(4-C6H4NH2)] +OTf- (7) in 72% yield.
Stabilization of polymers with styrenated-p-cresols
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, (2008/12/08)
Disclosed herein is a process for the preparation of a mixture of styrenated p-cresol species that is liquid at room temperature and has a viscosity of less than 40,000 cps at 25° C., wherein said process affords 2,6-distyrenated p-cresol assaying at 70% minimum by GC area percent, comprising reacting styrene with p-cresol at a molar ratio of 1.85 to 2.1:1, respectively, in the presence of an acid catalyst at elevated temperature, wherein said mixture comprises monostyrenated-p-cresol, distyrenated-p-cresol, and tristyrenated-p-cresol and exhibits an acid number of less than 0.1 mg KOH/gram.
Compositions and methods for inhibiting vinyl aromatic monomer polymerization
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, (2008/06/13)
Methods and compositions are provided for inhibiting the polymerization of vinyl aromatic monomers under distillation conditions. The compositions comprise a combination of a phenylenediamine compound and a hydroxylamine compound.
Preparation of N-substituted-N'-phenyl p-phenylenediamines
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, (2008/06/13)
The present invention relates to a process for the preparation of a N-substituted-N'-phenyl-p-phenylenediamine of the formula: STR1 comprising reacting (a) a mixture of (1) N-phenyl-p-quinoneimine of the formula: STR2 and (2) p-hydroxydiphenylamine in a mole ratio of N-phenyl-p-quinoneimine to p-hydroxydiphenylamine of from 1.5:1 to 1:1.5 with (b) a primary amine of the formula: in the presence of methanol wherein R1 is selected from the group of radicals consisting of alkyls having 1 to 20 carbon atoms, cycloalkyls having 6 to 8 carbon atoms and radicals of the structural formula: STR3 wherein R2 may be the same or different and is independently selected from the group of radicals consisting of hydrogen and an alkyl having 1 carbon atom, R3 is selected from the group of radicals consisting of an alkyl having 1 to 12 carbon atoms and n is an integer of from 0 to 6.
