The alkylation reaction of the ambident 2-hydroxypyridine anion was examined in ionic liquid media. Ionic liquids increase the alkylation reaction rate in comparison with molecular liquids, as well as the level of impact on the reaction rates of the counter ion and/or additives, and the distribution of isomers of the reaction products in trans-formations of the ambident 2-hydroxypyridine anion.
Fragmentation pathways of some imidazolium based zwitterionic liquids-3-(3-alkyl-1-imidazolio)- propane sulfonates and 3-(2-methyl-3-alkyl-1-imidazolio)-propane sulfonates -- have been studied by tandem electrospray mass spectrometry and collision-induced dissociation. The relative abundances of the lowest energy fragment ions depend on the length of the alkyl chain at the (II)N of the imidazolium ring and the cone voltage. The first fragment ions originate from the scission of C(non aromatic)-N bond of compounds investigated, but with increasing collision energy, scission of C-C bonds occurs. Aggregates of the general formula [(M + H)(x) + (M)(y)](+) (x;y = 1-2) formed. Methyl substituted zwitterionic liquids show higher molecular stability than 3-(3-alkyl-1-imidazolio)-propane sulfonates.
Alkylation of indole salts in different ionic liquids is reported. Ionic liquids increase the alkylation reaction rate of ambident indole anion and reduce the effects of counter ions and/or additives, the alkylation reaction rates being independent of the presence of small amounts of protic solvents or water.
Alkylation of the ambident indole anion in ionic liquids has been investigated. The reaction rate is greater in ionic liquids than in organic solvents. The polarity of certain ionic liquids has been determined to be located between methanol and acetonitrile.Conversions of ambident anions in ionic liquids (IL) have been little investigated in organic synthesis [1][2][3][4][5][6][7][8][9][10][11], in spite of the great interest of chemists in these solvents during the past 20 years [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. Only a few conversions of ambident anions of heterocyclic compounds are reported in the literature [1][2][3][4][5]. The poor availability of information does not permit generalizations on rules for such reactions and the forecasting of their results.The ambident anion of indole (1) forms several products in alkylation reactions, viz. the N-substituted compound 1-alkylindole 3, the C-substituted compound 3-alkylindole 4, and the N,C-disubstituted compound 1,3-dialkylindole 5 [32][33][34]. The rate of the alkylation reaction and the distribution of isomers in the mixture of products 3-5 depend on various factors, the properties of the solvents used, the form and charge of the cation, the structure of the alkylating agent, etc. [32][33][34]. The overall effect of these factors is considered in reactions which are carried out in molecular liquids (organic solvents), and a difference in their influence has N H N N N R N R N R R MY M + _ _ M + 1A 1B 1 R-X 2a-c 3 4 5 + + Y a = OMe, b Y = Bu, c Y = Me; 1 a M = Na, b M = Li, c M = MgI;2−5 a R = n-C 4 H 9 , b R = PhCH 2 , c R = CH 2 =CHCH 2 ; 2a 1 X = Cl, a 2 X = Br, a 3
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