- 2-amino-4,6-bis(benzyloxy)-5-nitroso-pyrimidine: Chains built from three-centre N-H...(N,O) and N-H...π(arene) hydrogen bonds
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The molecules of the title compound, C18H16N4O3, exhibit a very polarized molecular-electronic structure. The molecules are linked into chains by a combination of an asymmetric three-centre N-H...(N,O) hydrogen
- Quesada, Antonio,Low, John N.,Melguizo, Manuel,Nogueras, Manuel,Glidewell, Christopher
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- Amino-substituted O6-benzyl-5-nitrosopyrimidines: Interplay of molecular, molecular-electronic and supramolecular structures
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The structures of eight 2,4,6-trisubstituted-5-nitrosopyrimidines (one of which crystallizes in two polymorphs) have been determined, including seven O6-benzyl derivatives which are potential, or proven, in vitro inhibitors of the human DNA-repair protein O6-alkylguanine-DNA-transferase. In the derivatives having an amino substituent at the 4-position, an intramolecular N-H...O hydrogen bond with the nitroso O as an acceptor leads to an overall molecular shape similar to that of substituted purines. There is a marked propensity for these nitroso compounds to crystallize with Z′ = 2. The structure of an analogue with no nitroso group is also reported for comparative purposes. Compounds containing the N-alkyl substituents -NHCH2COOEt, -NHCH2CH2COOEt and -NHCH(CH2Ph)COOEt, derived from amino acid esters, exhibit a rich variety of conformational behaviour, and in all of the nitroso compounds the bond lengths provide strong evidence for a highly polarized electronic structure. Associated with this polarization is extensive charge-assisted hydrogen bonding between the molecules, leading to supra-molecular aggregation in the form of finite (zero-dimensional) aggregates, chains, molecular ladders, sheets and frameworks.
- Quesada, Antonio,Marchal, Antonio,Melguizo, Manuel,Nogueras, Manuel,Sanchez, Adolfo,Low, John N.,Cannon, Debbie,Farrell, Dorcas M. M.,Glidewell, Christopher
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