- Efficient synthesis of N-methylamides and amines via 4-(alkylamino)benzyl- N-methylamine as a new protecting group
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4-(Alkylamino)benzyl-N-methylamine is a good protecting group for the synthesis of N-methylamides and amines. The N-debenzylation of N-methylamides and amines can be carried out selectively and efficiently under condition using trifluoroacetic acid (TFA).
- Lee, Sang-Hak,Mu, Yu,Kim, Gun-Woo,Kim, Jin-Seok,Park, Seok-Hwi,Jin, Tian,Lee, Kee-Young,Ham, Won-Hun
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p. 1749 - 1764
(2013/09/12)
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- Lipase-catalyzed transformations using poly(ethylene glycol) as solvent
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Candida antarctica lipase catalyzes a number of elementary reactions like alcoholysis, ammoniolysis and aminolysis in poly(ethylene glycol) (PEG) media. Reaction rates were comparable to or better than those observed in conventional organic reaction media and ionic liquids. It is envisaged that PEGs could have added benefits for performing biotransformations with highly polar substrates, which are sparingly soluble in common organic solvents.
- Kidwai, Mazaahir,Poddar, Roona,Bhardwaj, Saurav
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experimental part
p. 113 - 118
(2011/12/15)
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- The ruthenium-catalyzed reduction and reductive N-alkylation of secondary amides with hydrosilanes: Practical synthesis of secondary and tertiary amines by judicious choice of hydrosilanes
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(Chemical Equation Presented) A triruthenium cluster, (μ3, η2,η3,η5-acenaphthylene)Ru 3(CO)7 (1) catalyzes the reaction of secondary amides with hydrosilanes, yielding a mixture of secondary amines, tertiary amines, and silyl enamines. Production of secondary amines with complete selectivity is achieved by the use of higher concentration of the catalyst (3 mol %) and the use of bifunctional hydrosilanes such as 1,1,3,3-tetramethyldisiloxane. Acidic workup of the reaction mixture affords the corresponding ammonium salts, which can be treated with a base, providing a facile method for isolation of secondary amines with high purity. In contrast, tertiary amines are formed with high selectivity by using lower concentration of the catalyst (1 mol %) and polymeric hydrosiloxanes (PMHS) as reducing agent. Reduction with PMHS encapsulates the ruthenium catalyst and organic byproducts to the insoluble silicone resin. The two reaction manifolds are applicable to various secondary amides and are practical in that the procedures provide the desired secondary or tertiary amine as a single product. The product contaminated with only minimal amounts of ruthenium and silicon residues. On the basis of the products and observed side products as well as NMR studies a mechanistic scenario for the reaction is also described.
- Hanada, Shiori,Ishida, Toshiki,Motoyama, Yukihiro,Nagashima, Hideo
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p. 7551 - 7559
(2008/02/12)
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- Reductions with lithium in low molecular weight amines and ethylenediamine
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Reductions of several types of compounds with lithium and ethylenediamine using low molecular weight amines as solvent are described. In all cases 1 mol of ethylenediamine or N,N'-dimethylethylenediamine per gram-atom of lithium was used. In some cases it was beneficial to add an alcohol as a proton donor. These reaction conditions were applied to the debenzylation of N-benzylamide and lactams which are refractory to hydrogenolysis with hydrogen and a catalyst. N-Benzylpilolactam 2, synthesized from pilocarpine hydrochloride in refluxing benzylamine, was debenzylated in good yield using 10 gram-atoms of lithium per mole (10 Li/mol) of 2 in n-propylamine. The debenzylation of N-benzyl-N-methyldecanoic acid amide, 4 (6 Li/mol), in t-butylamine/N,N'-dimethylethylenediamine gave N-methyldecanoic acid amide 6 in 70% yield. Alternatively, reduction of 4 (7 Li/mol) in t-butanol/n-propylamine/ethylenediamine gave n-decanal 12 in 36% yield. Using the same conditions, thioanisole, 1-adamantane-p-toluenesulfonamide, and 1-adamantane methyl p-toluenesulfonate were reduced with 3, 7, and 7.2 Li/mol of compound to give thiophenol (74%), adamantamine (91%), and 1-adamantane methanol (75%), respectively. In this solvent system naphthalene and 3-methyl-2-cyclohexene-1-one were reduced to isotetralin (74%) and 3-methyl cyclohexanone (quantitative) with 5 and 2.2 Li/mol of starting compound, respectively. Oximes and O-methyloximes were reduced to their corresponding amines using 5 and 8 Li/mol of compound, respectively. Anisole was also reduced to 1-methoxy-1,4-cyclohexadiene with 2.5 Li/mol of anisole. Undecanenitrile was reduced to undecylamine with 8.6 Li/mol. Additionally, a base-catalyzed formation of imidazolines from a nitrile and ethylenediamine was also explored.
- Garst,Dolby,Esfandiari,Fedoruk,Chamberlain,Avey
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p. 7098 - 7104
(2007/10/03)
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- Lithium and amine dissolving metal reduction
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The invention is directed to a process for reducing or reductively cleaving an organic compound susceptible to dissolving metal reduction comprising exposing the organic compound to a solution of lithium in a polyamine including at least two amino groups, selected from the group consisting of primary and secondary amino groups and mixtures thereof, e.g. ethylenediamine and R--NH2, optionally containing a lower alkyl alcohol, wherein R is chosen from the group consisting of ethyl, propyl, and butyl, including all straight and branched chain isomers thereof, for a time sufficient to effect reduction.
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