39799-77-4Relevant academic research and scientific papers
High-Field NMR Spectroscopy Reveals Aromaticity-Modulated Hydrogen Bonding in Heterocycles
Kakeshpour, Tayeb,Bailey, John P.,Jenner, Madison R.,Howell, Darya E.,Staples, Richard J.,Holmes, Daniel,Wu, Judy I.,Jackson, James E.
, p. 9842 - 9846 (2017)
From DNA base pairs to drug–receptor binding, hydrogen (H-)bonding and aromaticity are common features of heterocycles. Herein, the interplay of these bonding aspects is explored. H-bond strength modulation due to enhancement or disruption of aromaticity of heterocycles is experimentally revealed by comparing homodimer H-bond energies of aromatic heterocycles with analogs that have the same H-bonding moieties but lack cyclic π-conjugation. NMR studies of dimerization in C6D6 find aromaticity-modulated H-bonding (AMHB) energy effects of approximately ±30 %, depending on whether they enhance or weaken aromatic delocalization. The attendant ring current perturbations expected from such modulation are confirmed by chemical shift changes in both observed ring C?H and calculated nucleus-independent sites. In silico modeling confirms that AMHB effects outweigh those of hybridization or dipole–dipole interaction.
Metal-free C(sp2)-H functionalization of azoles: K2CO3/I2-mediated oxidation, imination, and amination
Das, Ranajit,Banerjee, Mainak,Rai, Rakesh Kumar,Karri, Ramesh,Roy, Gouriprasanna
, p. 4243 - 4260 (2018/06/22)
The direct C2-H oxidation and imination of a wide variety of azoles was achieved by using a commercially available simple K2CO3/I2 reagent combination. The iodinated azole adduct, produced via the in situ generation of N-heterocyclic carbene, is the key intermediate for C2-H oxidation, imination, and amination of azoles. Significantly, these reactions proceed under mild conditions with high to excellent yields, are scalable to large quantity and exhibit a broad substrate scope. Interestingly, this direct C2-H imination method allowed us to access various pharmacologically active N6-alkyl or N6-aryl substituted benzimidazoquinazolinone scaffolds through intramolecular C-H imination in a sequential one-pot reaction.
Photochemistry of N-(pyrimidin-2-one-4-yl)pyridinium derivatives. The ring contraction of pyrimidinone into imidazolinone
Wenska,Skalski,Paszyc,Gdaniec
, p. 2178 - 2184 (2007/10/03)
Photochemical reactions (λ > 300 nm) of N-(1-methylpyrimidin-2-one)- and N-(1,5-dimethyl-pyrimidin-2-one)pyridinium chlorides were studied in deoxygenated aqueous solution at various pH's. Only the former compound was found to be reactive under these conditions to give pyrimidine ring contraction photoproducts 1-methyl-4-imidazolin-2-one and 1-methyl-4-imidazolin-2-one-5-carboxyaldehyde, with pH-dependent chemical yields. The photochemical pyrimidine ring contraction reaction does not occur for other photochemically reactive pyrimidin-2-ones bearing 3-methylimidazolium-1,1,2,4-triazol-1-yl, or imidazol-1-yl as substituents at the C-4 position. The suggested mechanism of the reaction involves the addition of water to the pyrimidinone part of the N-(1-methylpyrimidin-2-one)pyridinium salt in the excited triplet state as the primary photochemical step. Addition of alcohol to the pyridinium ring was found to be the major reaction under irradiation of N-(1-methylpyrimidin-2-one-4-yl)pyridinium chloride in methanol.
Imidazolin-2-ones
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, (2008/06/13)
A compound having the formula: STR1 wherein R, R1 and R2 are independently selected from hydrogen; hydroxy; fluorine; bromine; chlorine; C1 -C20 alkyl; C2 -C20 alkenyl; C2 -C20 alkynyl; C3 -C10 cycloalkyl; C2 -C20 (monohydroxy or polyhydroxy)alkyl; C1 -C20 (monohalo or polyhalo)alkyl; carboxy; C1 -C20 alkylcarboxy; C1 -C20 alkenylcarboxy; C1 -C20 carboxyalkyl; C1 -C20 alkanoyl; C1 -C20 alkanoyloxy; C1 -C20 alkoxycarbonyl; carbamoyl; carbamyl; C1 -C20 alkylcarbamyl; sulfo; C1 -C20 alkylsulfonyl; C1 -C20 alkylsulfinyl; C1 -C20 alkylsulfoxide; C1 -C20 alkylsulfone; thio; C1 -C20 alkylthio; amino; nitro; C1 -C20 alkylamino; C1 -C20 aminoalkyl; substituted or unsubstituted phenyl or benzyl, the substituents being selected from hydroxy, fluorine, bromine, chlorine, C1 -C20 alkyl, C2 -C20 alkenyl, C2 -C20 (monohydroxy or polyhydroxy)alkyl, X is methyl or oxygen and n is 0 to 20. The invention is also directed to a method for increasing the topical penetration of a physiologically active agent across the skin or membrane of a mammalian organism. Also claimed is a pharmaceutical composition and a novel method for preparing 1-substituted-4-imidazolin-2-one.
AN IMPROVED SYNTHESIS OF 1-ALKYL-4-IMIDAZOLIN-2-ONES
Wong, Ooi,Tsuzuki, Noriko,Richardson, Mark,Rytting, Howard,Konishi, Ryoji,Higuchi, Takeru
, p. 3153 - 3158 (2007/10/02)
Two 1-alkyl-4-imidazolin-2-ones were prepared by acid-catalysed cyclization of N-(2,2-dialkoxyethyl)-N-alkylureas with improved yields of over 90 percent.The amount of HCl used in the reaction and the proper isolation procedure are the important factors in obtaining the high yields.
Effect of structural modification of the hydrantoin ring on anticonvulsant activity
Cortes,Liao,Watson,Kohn
, p. 601 - 606 (2007/10/02)
Selectively substituted hydantoins (15 examples), 4-hydroxy-2-imidazolidinones (13 examples), 2-imidazolones (10 examples), 2-imidazolidinones (four examples), vicinal diamines (two examples), and simple amino acid derivatives (four examples) have been pr
