- Synthesis of 6-arylisocytosines and their potential for hydrogen bonding interactions
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Abstract The synthesis of a number of 6-arylisocytosines, including linked bis-isocytosines, from the reaction of guanidine with β-ketoesters is described. The compounds were investigated for their ability to form hydrogen-bonded structural networks, and for their potential interactions with the telomeric quadruplex forming sequence AGGG(TTAGGG)3.
- Patel, Alpa,Lewis, William,Searle, Mark S.,Stevens, Malcolm F.G.,Moody, Christopher J.
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- Strong dimerization of ureidopyrimidones via quadruple hydrogen bonding
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6-Methyl-2-butylureidopyrimidone dimerizes via four hydrogen bonds in the solid state as well as in CHCl3 solution via a donor-donor-acceptor-acceptor (DDAA) array of hydrogen bonding sites in the 4[1H]-pyrimidinone tautomer. An intramolecular hydrogen bond from the pyrimidine NH group to the urea oxygen atom preorganizes the molecules for dimerization. The dimerization constant of the dimer in CHCl3 exceeds 106 M-1. In CHCl3 containing DMSO, the dimer is in equilibrium with the monomeric G[1H]-pyrimidinone tautomer. In 6-phenyl-2-butylureidopyrimidone, the 4[1H]-pyrimidinone tautomer coexists with the pyrimidin-4-ol form, which dimerizes with similar high dimerization constants via four hydrogen bonds in a DADA array. The latter tautomer predominates in derivatives with electronegative 6-substituents, like 6-nitrophenyl- and 6-trifluoromethyl-2-butylureidopyrimidone Due to its simple preparation and high dimerization constant, the ureidopyrimidone functionality is a useful building block for supramolecular chemistry.
- Beijer, Felix H.,Sijbesma, Rint P.,Kooijman, Huub,Spek, Anthony L.,Meijer
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p. 6761 - 6769
(2007/10/03)
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