- Synthesis of 5-methylidenehexahydropyrrolo[l,2-a]imidazoles and 6-methylideneoctahydropyrrolo[l,2-a]pyrimidines by the reaction of 1-alkynyl-1-chlorocyclopropanes with lithium derivatives of 1,2- and 1,3-diaminoalkanes
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A reaction of 1-alkynyl-1-chlorocyclopropanes with excess of lithium derivative of 1,2-diaminoethane leads to 5-methylidenehexahydropyrrolo[l,2-a] imidazoles in 35-72% yields, whereas analogous reaction with lithium derivative of 1,3-diaminopropane gives 6-methyl-ideneoctahydropyrrolo[l,2-a]pyrimidine in up to 50% yield. A mechanism of these unusual multi-step processes includes dehydrochlorination of 1-alkynyl-1-chlorocyclopropanes to form conjugated alkynylcyclopropenes capable of addition of monoalkylamide ions at the double bond, leading to the corresponding secondary cyclopropylamines; the latter under the reaction conditions isomerize to the linear imines, which further undergo a cascade cyclization with sequential involvement of the C=N and C≡C bonds.
- Shavrin,Gvozdev,Nefedov
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experimental part
p. 1451 - 1458
(2011/04/16)
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- Some reactions of ammonia and primary amines with propanal, 2-chloroethanal, 2,2-dichloroethanal and 2,2,2-trichloroethanal in acetonitrile
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The reaction of ammonia with propanal in acetonitrile produces the hexahydrotriazine, 1, in good yield. The corresponding reaction of chloroethanal yields the cyclic trimer 16 but only in poor yield. Increasing chloro-substitution in the aldehyde stabilises the initially formed carbinolamines and disfavours trimerisation. Imines formed by reaction of primary amines with the aldehydes are relatively stable. Those formed from aliphatic amines may undergo slow dimerisation by C-C bond formation and this may be accompanied by loss of amine to yield products containing a conjugated double-bond system. Kinetic and equilibrium data are reported for both the forward and reverse reactions involving interconversion of propanal and ammonia with 1 in acetonitrile-water mixtures. The results indicate that dehydration of the carbinolamine is rate determining.
- Crampton, Michael R.,Lord, Simon D.,Millar, Ross
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p. 909 - 914
(2007/10/03)
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- SYNTHESE D'IMINES LINEAIRES NON-STABILISEES PAR REACTIONS GAZ-SOLIDE SOUS VIDE(1).
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Unstabilized imines are synthetized in gram-scale by vacuum dehydrochlorination of N-chloroalkylamines and by vacuum dehydrocyanation of α-aminonitriles on solid base.All the new compounds are characterized at low temperature by 1H, 13C NMR and IR spectroscopy.
- Guillemin, Jean-Claude,Denis, Jean-Marc
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p. 4431 - 4446
(2007/10/02)
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- The Synthesis of NH Aldimines and Derivatives by Spontaneous and Base-catalysed Decomposition of Oxaziridines
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A range of oxaziridines containing N-methylene substituents has been synthesized by peracid oxidation of the corresponding fluorenylidene N-alkylamines.Spontaneous and tertiary amine base-catalysed decomposition of the oxaziridines into unstable NH aldimines and derivatives was observed.Acrylaldehyde, 2-methylacrylaldehyde, and benzaldehyde NH imines have been identified as initial products from decomposition of the corresponding oxaziridines. 2,4,6-Trialkylhexahydro-1,3,5-triazines, N,N'-dialkylidene-1,1-diaminoalkanes, N,N'-diarylidene-1,1-diaminoalkanes, and N-isobutylidene-2-methylpropenylamine were among the isolated products formed via the undetected alkyl aldehyde NH imines resulting from oxaziridine decomposition.
- Boyd, Derek R.,Coulter, Peter B.,Hamilton, Robert,Thompson, Norris T.,Sharma, Narain D.,Stubbs, Michael E.
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p. 2123 - 2128
(2007/10/02)
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- Pyridines and dihydropyridines
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A process of preparing alkyl (or aralkyl) pyridines and N-substituted alkyl (or aralkyl) dihydropyridines which comprises treating a2,5,6,8,9-pentaalkyl (or aralkyl) substituted 1,3,7-triazabicyclo (3,3,1) non-3-ene with a Lewis acid.
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