121751-72-2Relevant academic research and scientific papers
Synthesis and study of 1-aryl-1H-4,5-dihydroimidazoles
Perillo, Isabel,Caterina, M. Cristina,Lopez, Julieta,Salerno, Alejandra
, p. 851 - 856 (2007/10/03)
An easy synthesis of 1-aryl-1H-4,5-dihydroimidazoles 1 by cyclocondensation of N-aryl-N′-formylethylenediamines 2 is described. Such precursors were synthesized by selective formylation of N-arylethylenediamines 3 with p-nitrophenyl formate. Cyclizations were performed using trimethylsilyl polyphosphate. Chemical properties of compounds 1, typical of amidine system, were studied. Reaction of 1 with methyl iodide leads to the corresponding 1-aryl-3-methyl-1H-4,5-dihydroimidazolium salts 5. Reduction of dihydroimidazoles 1 with sodium cyanoborohydride provides a convenient access to N-aryl-N′-methylethylenediamines 4.
Synthesis of substituted 1H-4,5-dihydroimidazolium salts by dehydrogenation of imidazolidines
Salerno, Alejandra,Caterina, Cristina,Perillo, Isabel A.
, p. 3369 - 3382 (2007/10/03)
A study is presented on the scope of the method to obtain 1H-4,5-dihydroimidazolium salts 3 by dehydrogenation of 1,3-di and 1,2,3-trisubstituted imidazolidines 2. Of the dehydrogenating agents used, N-bromoacetamide leads to the best results, providing a
Nucleophilic Addition to Substituted 1H-4,5-Dihydroimidazolium Salts
Salerno, Alejandra,Ceriani, Vanina,Perillo, Isabel A.
, p. 709 - 716 (2007/10/03)
1H-4,5-Dihydroimidazolium salts 1 react readily with nucleophilic reagents originating cyclic products which may be stable or become transformed into acyclic compounds maintaining the structural ethylenediamine unit. With methylmagnesium iodide compound le affords the expected imidazolidine, but in the case of substituted 1-aryl-3-methyl-2-phenyl salts 1b-d the N-aryl-N'-methylethylenediamines 3b-d and acetophenone (4) were isolated, the process representing the transfer of the C-2 unit to a nucleophilic carbon. With alkaline cyanides salts 1 react efficiently affording α,α-diaminonitriles 5. In these compounds the cyano group may be readily substituted by nucleophiles (hydroxyl anion, species with nucleophilic carbon and reagents that act by hydride ion transfer), in a way similar to the salts but with better yields.
Disproportionation reactions from glyoxal and difunctional basic molecules
Chassonnery, Dominique,Chastrette, Francine,Chastrette, Maurice,Blanc, Alain,Mattioda, Georges
, p. 188 - 199 (2007/10/02)
Glyoxal was reacted with basic difunctional molecules in order to study the disproportionation reaction.Symmetrical and unsymmetrical 1,2-diamines gave rise to piperazinones; their 1,3-diamine analogues yielded hexahydrodiazepinones; and β-aminoalcohols yielded morpholinones and hydroxyamino acids.Aminoamides gave the expected piperazinediones in low yields and no reaction was observed with diamides.The first step of the reaction consists of the formation of dihydroxy compounds, from which the more basic function assists the departure of OH, providing the expected more stable iminium ion.The observed regioselectivity is consistent with the relative basicities of the two functions; a 100percent regioselectivity is observed with aminoalcohols (giving way to morpholinones and not to amides), a good regiposelectivity with most of N-alkyl-N'-aryl-diamines and a rather low one with N-methyl-N'-ethyl- or N-methyl-N'-p-methoxyphenyl-diamines.Geometry factors were related to the better yield obtained with 1,2-diamines compared with 1,3-diamines.The mechanism was investigated.When deutared glyoxal and diamines were reacted in D2O, incorporation of deuterium was observed, in accordance with the formation of an enolate in the course of the oxidoreduction.The low reactivity of aminoamides and the observed regioselectivities could be related to both the weak basicity of the function that is supposed to allow the formation of the iminium ion and the basicity of the other function that accepts a positive charge and which, if too weak, impedes the reaction because of the instability of the intermediate iminium ion. glyoxal / disproportionation rules / basic difunctional molecules
