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Articles 1 - 11 of 11

Full-Text Articles in Physical Sciences and Mathematics

Stereoselective Synthesis Of 3,7-Diarylaminocholestanes By Titanium-Mediated Reductive Amination, Md Wasi Ahmad, Hong Seok Kim Dec 2013

Stereoselective Synthesis Of 3,7-Diarylaminocholestanes By Titanium-Mediated Reductive Amination, Md Wasi Ahmad, Hong Seok Kim

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

An efficient method for the synthesis of aryl aminocholestanes, using a chlorotriisopropoxytitanium (IV)-mediated reductive amination reaction of 5a-cholestane-3,7-dione, is reported. A series of 3, 7-diarylaminocholestane derivatives were prepared according to this methodology in up to 98% yield. These compounds were primarily characterized by 1H NMR, 13C NMR, and mass spectrometry.


Selective Fluorescence Sensing Of Salicylic Acid Using A Simple Pyrene Appended Imidazole Receptor, Md Wasi Ahmad, Bo Yeon Kim, Hong Seok Kim Dec 2013

Selective Fluorescence Sensing Of Salicylic Acid Using A Simple Pyrene Appended Imidazole Receptor, Md Wasi Ahmad, Bo Yeon Kim, Hong Seok Kim

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

A simple salicylic acid selective fluorescence receptor 1 was designed by combining 1-pyrenecarboxaldehyde and 1-(3-aminopropyl)imidazole. The selective sensing of salicylic acid resulted in a significant increase in monomer emissions due to the p–p interactions between the benzene and pyrene rings. The nature of the interactions between receptor 1 and salicylic acid was investigated further by 1H NMR spectroscopy, and the energy minimised structure of the complex between receptor 1 and salicylic acid was optimised. Receptor 1 showed the highest binding constant with 5-nitrosalicylic acid among all the aromatic carboxylic acids tested. 5-Nitrosalicylic acid formed a complex with receptor 1 at …


Bovine Serum Albumin (Bsa) And Cleaved-Bsa Conjugated Ultrasmallgd2o3nanoparticles: Synthesis, Characterization, And Application To Mri Contrast Agents, Md Wasi Ahmad, Cho Rong Kim, Jong Su Baeck, Yongmin Chang, Tae Jeong Kim, Ji Eun Bae, Kwon Seok Chae, Gang Ho Lee Dec 2013

Bovine Serum Albumin (Bsa) And Cleaved-Bsa Conjugated Ultrasmallgd2o3nanoparticles: Synthesis, Characterization, And Application To Mri Contrast Agents, Md Wasi Ahmad, Cho Rong Kim, Jong Su Baeck, Yongmin Chang, Tae Jeong Kim, Ji Eun Bae, Kwon Seok Chae, Gang Ho Lee

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

No abstract provided.


Surface Coated Eu(Oh)3 Nanorods: A Facile Synthesis, Characterization, Mr Relaxivities And In Vitro Cytotoxicity, Krishna Katte, Ja Young Park, Wenlong Xu, Badrul Alam Bony, Woo Cheol Heo, Tirusew Tegafaw, Cho Rong Kim, Md Wasi Ahmad, Seonguk Jin, Jong Su Baeck, Yongmin Chang, Tae Jeong Kim, Ji Eun Bae, Kwon Seok Chae, Ji Yun Jeong, Gang Ho Lee Dec 2012

Surface Coated Eu(Oh)3 Nanorods: A Facile Synthesis, Characterization, Mr Relaxivities And In Vitro Cytotoxicity, Krishna Katte, Ja Young Park, Wenlong Xu, Badrul Alam Bony, Woo Cheol Heo, Tirusew Tegafaw, Cho Rong Kim, Md Wasi Ahmad, Seonguk Jin, Jong Su Baeck, Yongmin Chang, Tae Jeong Kim, Ji Eun Bae, Kwon Seok Chae, Ji Yun Jeong, Gang Ho Lee

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

No abstract provided.


Selective Recognition Of H2po4 By A Cholestane-Imidazole-Zinc Ensemble, Jyoti Ramesh Jadhav, Md Wasi Ahmad, Hong Seok Kim Dec 2011

Selective Recognition Of H2po4 By A Cholestane-Imidazole-Zinc Ensemble, Jyoti Ramesh Jadhav, Md Wasi Ahmad, Hong Seok Kim

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

A new facile amphiphile cholestane-based zinc complex 4 containing a 3-aminopropylimidazole moiety at the 3a and 7a positions of cholestane was designed and synthesized. Recognition selectivity of the new receptor 4 with various anions was assessed by 1H NMR titration. Dihydrogen phosphate showed the highest binding affinity among all the tested anions


Fluorescein-Polyethyleneimine Coated Gadolinium Oxide Nanoparticles As T1 Magnetic Resonance Imaging (Mri)–Cell Labeling (Cl) Dual Agents, Wenlong Xu, Ja Young Park, Krishna Kattel, Md Wasi Ahmad, Badrul Alam Bony, Woo Choul Heo, Seonguk Jin, Jang Woo Park, Yongmin Chang, Tae Jeong Kim, Ji Ae Park, Ji Yeon Do, Kwon Seok Chae, Gang Ho Lee Dec 2011

Fluorescein-Polyethyleneimine Coated Gadolinium Oxide Nanoparticles As T1 Magnetic Resonance Imaging (Mri)–Cell Labeling (Cl) Dual Agents, Wenlong Xu, Ja Young Park, Krishna Kattel, Md Wasi Ahmad, Badrul Alam Bony, Woo Choul Heo, Seonguk Jin, Jang Woo Park, Yongmin Chang, Tae Jeong Kim, Ji Ae Park, Ji Yeon Do, Kwon Seok Chae, Gang Ho Lee

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

We report the synthesis, characterization and application of highly water-soluble fluoresceinpolyethyleneimine (PEI) coated gadolinium oxide (Gd2O3) nanoparticles to magnetic resonance imaging (MRI) and cell labeling (CL). The average particle diameter and average hydrodynamic diameter were estimated to be 3.92 and 7.5 nm, respectively. Fluorescein-PEI was prepared from EDC/NHS coupling method. The surface coating was characterized by the FT-IR absorption spectrum and the surface coating amount was estimated to be 22.42 wt% from a TGA analysis, corresponding to 0.65 nm22 grafting density. The fluorescein-PEI coated gadolinium oxide nanoparticles showed r1 and r2 of 6.76 and 20.27 s21mM21, respectively, and a strong …


A New Acridine-Imidazolium-Based Cholestane Receptor For Anion Sensing, Jyoti Ramesh Jadhav, Md Wasi Ahmad, Hong Seok Kim Dec 2010

A New Acridine-Imidazolium-Based Cholestane Receptor For Anion Sensing, Jyoti Ramesh Jadhav, Md Wasi Ahmad, Hong Seok Kim

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

A new highly selective receptor (3) based on an acridine-imidazolium functionalized cholestane for anion sensing was designed and synthesized. A binding study of 3 with various anions was assessed by UV-vis and fluorescence spectroscopies in dry CH3CN. Receptor 3 showed the highest selectivity toward hydrogen pyrophosphate.


Pyrenyl-Appended Imidazolium Receptor For Selective Fluorescence Sensing Of Oxalic Acid, Md Wasi Ahmad, Sung Hong Kim, Hong Seok Kim Dec 2010

Pyrenyl-Appended Imidazolium Receptor For Selective Fluorescence Sensing Of Oxalic Acid, Md Wasi Ahmad, Sung Hong Kim, Hong Seok Kim

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

A new fluorescent imidazolium-based cholestane receptor 4 bearing a pyrene moiety was synthesized. The binding ability of 4 toward various dicarboxylic acids was examined by UV–vis and fluorescence spectroscopy. Receptor 4 showed the highest binding constant for oxalic acid among all the tested dicarboxylic acids. Oxalic acid formed a complex with 4 with a 1:2 ratio in ethanol.


Ticl(Oipr)3-Mediated One-Pot Reductive Amination Of 1,1'-Diacetylferrocene With Aryl Amines, Md Wasi Ahmad, Sang Yeon Lee, Tae Jeong Kim, Hong Seok Kim Dec 2010

Ticl(Oipr)3-Mediated One-Pot Reductive Amination Of 1,1'-Diacetylferrocene With Aryl Amines, Md Wasi Ahmad, Sang Yeon Lee, Tae Jeong Kim, Hong Seok Kim

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

No abstract provided.


New 2-Aminoethylimidazole-Based Dicarboxylic Acid Receptor Derived From Cholestane, Jyoti Ramesh Jadhav, Md Wasi Ahmad, Hong Seok Kim Dec 2009

New 2-Aminoethylimidazole-Based Dicarboxylic Acid Receptor Derived From Cholestane, Jyoti Ramesh Jadhav, Md Wasi Ahmad, Hong Seok Kim

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

A new facial amphiphile cholestane-based receptor 1 containing a 2-imidazolylethylamino moiety at the 3a and 7a positions of cholestane was synthesized. Recognition selectivity of the new receptor 1 with various dicarboxylic acids was assessed by 1H NMR titration. Maleic acid showed the highest binding constant among all the tested acids


Synthesis Of Facial Amphiphile 3,7-Diamino-5Α-Cholestane Derivatives As A Molecular Receptor, Md Wasi Ahmad, Young Mee Jung, Sharaf Nawaz Khan, Hong Seok Kim Dec 2008

Synthesis Of Facial Amphiphile 3,7-Diamino-5Α-Cholestane Derivatives As A Molecular Receptor, Md Wasi Ahmad, Young Mee Jung, Sharaf Nawaz Khan, Hong Seok Kim

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

A series of facial amphiphiles 3,7-diaminocholestane were synthesized from 3,7-diketocholestane via 2 sequential reductive aminations and anion recognition was evaluated with acetate, chloride, bromide, fluoride and phosphate anions. The stereo-selective reductive amination protocol was utilized to synthesized facial amphiphiles afforded receptors in high yields. The molecular receptor 2 showed the highest binding constant with acetate in a 1:1 ratio.