- Nonstabilised azomethine ylids from n-oxides: Unravelling the deprotonation of n-methylmorpholine n-oxide
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Nonstabilised azomethine ylids (NAYs) are useful 1,3-dipoles, but their synthetic applications are restricted by the high temperatures often needed for their generation, and by an incomplete understanding of the effect of heteroatoms in cyclic systems. We have examined the behaviour of N-methylmorpholine N-oxide (NMO) as a NAY precursor in the Roussi reaction (low-temperature reaction of an N-oxide with strong base). The choice of base is critical to achieving cycloadduct formation. We report synthetic and computational (density functional theory) investigations of the products obtained with different bases and their mechanisms of formation.
- Mirzayans, Paul Malek,Krenske, Elizabeth H.,Williams, Craig M.
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- pH-Sensitive Polycations for siRNA Delivery: Effect of Asymmetric Structures of Tertiary Amine Groups
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pH-sensitive polyelectrolytes provide enormous opportunity for siRNA delivery. Especially, their tertiary amine structures can not only bind genes but also act as pH-sensitive hydrophobic structure to control genes release. However, the influence of molecular structures on siRNA delivery still remains elusive, especially for the asymmetric alkyl substituents of the tertiary amine groups. Herein, a library of N-methyl-N-alkyl aminoethyl methacrylate monomers (MsAM) with asymmetric alkyl substituents on the tertiary amine group is synthesized and used to prepare a series of tri-block polycationic copolymers poly(aminoethyl methacrylate)-block-poly (N-methyl-N-alkyl aminoethyl methacrylate)-block-poly(ethylene glycol methacrylate) (PAMA-PMsMA-PEG). And the properties of these polycations and their self-assembled micelles are characterized, including molecular structure, proton buffering capacity, pH-sensitivity, size, and zeta potential. With the length increase of one alkyl substituent, the proton buffering capacity of both monomers and polycations is demonstrated to be narrowed down. The siRNA delivery efficiency and cytotoxicity of these micelles are also evaluated on HepG2 cells. In particular, poly(aminoethyl methacrylate)-block-poly(N-methyl-N-ethyl aminoethyl methacrylate)-block-poly(ethylene glycol methacrylate) (PAMA-PMEMA-PEG) elicited the best luciferase knockdown efficiency and low cytotoxicity. Besides, PAMA-PMEMA-PEG/siRRM2 also induced significant anti-tumor activity in vitro. These results indicated PAMA-PMEMA-PEG has potential for further use in the design of gene vehicles with the improved efficiency of siRNA delivery.
- Yang, Qinping,Dong, Yanliang,Wang, Xuanyu,Lin, Zhihao,Yan, Mingyu,Wang, Weiwei,Dong, Anjie,Zhang, Jianhua,Huang, Pingsheng,Wang, Changrong
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- PYRROLO[3,2-C]PYRIDIN-4-ONE DERIVATIVES AS PFK INHIBITORS USEFUL FOR THE TREATMENT OF PROTOZOAL INFECTIONS
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The invention described herein relates to compounds of formula I, or salts, hydrates and solvates thereof. (I) In other aspects the invention relates to pharmaceutical compositions comprising compounds defined herein, the use of the compounds defined herein in therapy, including for the treatment of a disease or condition mediated by infection by a protozoal parasite, such as trypanosomiasis.
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Paragraph 00350-00354
(2019/06/17)
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- DIALKYLAMINO ALKYL ESTERS OF PIVAGABINE AS MEDICAMENTS FOR THE TREATMENT OF CENTRAL NERVOUS SYSTEM DISORDERS
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The present embodiments are related to the compound of Formula 1 or Formula 2 below and pharmaceutical formulations thereof as well as treatments for a wide variety of Central Nervous System disorders with the pharmaceutical formulations. Some embodiments include the use of a variety of the instant compounds which surprisingly and advantageously exhibit improved pharmacokinetic and therapeutic profiles in comparison to pivagabine.
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Page/Page column 75-76
(2008/12/06)
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- Continuous chemoselective methylation of functionalized amines and diols with supercritical methanol over solid acid and acid-base bifunctional catalysts
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The selective N-methylation of bifunctionalized amines with supercritical methanol (scCH3OH) promoted by the conventional solid acids (H-mordenite, β-zeolite, amorphous silica-alumina) and acid-base bifunctional catalysts (Cs-P-Si mixed oxide and γ-alumina) was investigated in a continuous-flow, fixed-bed reactor. The use of scCH 3OH in the reaction of 2-aminoethanol with methanol (amine/CH 3OH = 1/10.8) over the solid catalysts led to a significant improvement in the chemoselectivity of the N-methylation. Among the catalysts examined, the Cs-P-Si mixed oxide provided the most efficient catalyst performance in terms of selectivity and reactivity at 300 °C and 8.2 MPa; the N-methylation selectivity in the products reaching up to 94% at 86% conversion. The present selective methylation was successfully applied to the synthesis of N-methylated amino alcohols and diamines as well as O-methylated ethylene glycol. Noticeably, ethoxyethylamine was less reactive, suggesting that the hydroxy group of the amino alcohols is a crucial structural factor in determining high reactivity and selectivity, possibly because of the tethering effect of another terminus, a hydroxo group, to the catalyst surface. The magic-angle-spinning NMR spectroscopy and X-ray diffraction analysis of the Cs-P-Si mixed oxide catalyst revealed that the acidic and basic sites originate from P2O5/SiO2 and Cs/SiO2, respectively, and the weak acid-base paired sites are attributed to three kinds of cesium phosphates on SiO2. The weak acid-base sites on the catalyst surface might be responsible for the selective dehydrative methylation.
- Oku, Tomoharu,Arita, Yoshitaka,Tsuneki, Hideaki,Ikariya, Takao
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p. 7368 - 7377
(2007/10/03)
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- Enhanced product selectivity in continuous N-methylation of amino alcohols over solid acid-base catalysts with supercritical methanol
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The unique properties of supercritical fluids can be exploited for fine-tuning product selectivity. Under the conditions listed for the N-methylation of amino alcohols (see scheme) over solid acid-base bifunctional catalysts, the total yield and product selectivity could be improved. Enhanced product selectivity might be attributed to the milder reaction conditions possible with supercritical methanol, as well as the increased concentration of methanol on the catalyst.
- Oku, Tomoharu,Ikariya, Takao
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p. 3476 - 3479
(2007/10/03)
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