Search Results

You are looking at 1 - 10 of 91 items for :

  • "organic synthesis" x
Clear All

Abstract

The generation of stereochemically rich benzothiaoxazepine-1,1´-dioxides for enrichment of high-throughput screening collections is reported. Utilizing a microwave-assisted, continuous-flow organic synthesis platform (MACOS), scale-out of core benzothiaoxazepine-1,1´-dioxide scaffolds has been achieved on multigram scale using an epoxide opening/SNAr cyclization protocol. Diversification of these sultam scaffolds was attained via a microwave-assisted intermolecular SNAr reaction with a variety of amines. Overall, a facile, two-step protocol generated a collection of benzothiaoxazepine-1,1´-dioxides possessing stereochemical complexity in rapid fashion, where all eight stereoisomers were accessed from commercially available starting materials.

Restricted access

Abstract

A microwave-assisted, continuous-flow organic synthesis (MACOS) protocol for the synthesis of functionalized 1,2,5-thiadiazepane 1,1-dioxide library, utilizing a one-pot elimination and inter-/intramolecular double aza-Michael addition strategy is reported. The optimized protocol in MACOS was utilized for scale-out and further extended for library production using a multicapillary flow reactor. A 50-member library of 1,2,5-thiadiazepane 1,1-dioxides was prepared on a 100- to 300-mg scale with overall yields between 50 and 80% and over 90 % purity determined by proton nuclear magnetic resonance (1H-NMR) spectroscopy.

Restricted access

Abstract  

We reported the synthesis and labeling of one tetradentate and two pentadentate amino-phenol ligands with technetium-99m by the direct pertechnetate addition and by ligand exchange methods. Labeling by direct pertechnetate addition was attended by adding pertechnetate eluate to the ethanolic solution of the amino-phenol ligands at pH 9. Stannous chloride dihydrate was used as reducing agent. Exchange studies were carried out via the use of the following 99mTc-chelates: 99mTc-DTPA, 99mTc-gluconate, 99mTc-tartrate and 99mTc-citrate complexes. Ligand exchange method was achieved by incubation the ligand solutions with 99mTc-co-ligands complexes in 0.05M bicarbonate buffer pH 9. At this pH value the 99mTc-co-ligands dissociated and the more stable new 99mTc-ligands were formed with high radiochemical yield 95%. The radiochemical yield of 99mTc-labeled amino-phenol ligands were estimated by solvent extraction, electrophoresis and HPLC methods. The produced technetium-99m amino-phenol complexes were neutral, lipophilic and stable during the period of 24 hours.

Restricted access

Abstract  

This work focuses on the “3 + 1” mixed ligands of 99mTc labeled Gabapentin as α2δ receptor imaging agents in the brain. Gabapentin 1-(aminomethyl)cyclohexanacetic acid as monodentate and two tridentates: tridentate A; 3-(2-imino-thiozolidin-4-one)-quinozoline-4-(3H)-one and tridentate B; N-(4-chlorophenyl)-2-imino-2H-chromene-3-Carbothioamide which were synthesized and characterized by infrared analysis (IR), 1H nuclear magnetic resonance (NMR), and mass spectrum. 99mTc-complexes were prepared by the “3 + 1” mixed ligand approach. The labeling conditions were optimized and the complexes was extracted by chloroform and purified by high performance liquid chromatography. 99mTc-complexs were lipophilic and stable for at least 8–12 h at room temperature. The biodistribution of the 99mTc-complexes was evaluated in mice. The brain uptake was 4.5% and 3.5% ID/g (percentage of the injected dose per gram) at 5 min, and the retention was 1.5% and 1.7% ID/g at 120 min for 99mTc-complex A and 99mTc-complex B, respectively.

Restricted access

In recent papers, laboratory microfluidic electrolysis cells with extended channel lengths (0.7–2 m) and narrow interelectrode gap (≤0.5 mm) have been introduced; these cells permit high conversions at a flow rate consistent with the synthesis of products at a rate of multigrams/hour. Such microflow electrolysis cells must be operated with appropriate control parameters if good performance is to be achieved; thus, this paper emphasizes the correct selection of cell current, flow rate, and counter electrode chemistry. It is also shown that, within the limitations, the cells can be used for a number of electrosyntheses in the synthetic laboratory.

Restricted access

“ Submillisecond Organic Synthesis: Outpacing Fries Rearrangement through Microfluidic Rapid Mixing ” Science 2016 , 352 , 691 – 694 J. Ehgartner , P. Sulzer , T

Restricted access

.; Sato M.; Ryu, I. Synlett 2008 , 151â€"163; (d) Yoshida, J. Flash Chemistry: Fast Organic Synthesis in Microsystems ; Wiley-VCH: Weinheim, 2008; (e) Chemical Reactions and Processes under Flow Conditions ; Luis S. V.; Garcia-Verdugo, E., Eds.; Royal

Open access

Organic Synthesis “ High-throughput generation of emulsions and microgels in parallelized microfluidic drop-makers prepared by rapid prototyping ” T. Femmer , A. Jans , R. Eswein , N. Anwar , M. Moeller , M

Restricted access

“ Continuous flow formulation and functionalization of magnesium di-hydroxide nanorods as a clean nano-fire extinguisher ” S. Elbasuney , S. F. Mostafa Powder Technology 2015 , 278 , 72 – 83 “ Machine-assisted organic synthesis ” S

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: Ju-Lan Zeng, Sai-Bo Yu, Bo Tong, Li-Xian Sun, Zhi-Cheng Tan, Zhong Cao, Dao-Wu Yang and Jing-Nan Zhang

Introduction Protection of organic functions plays a fundamental role in the field of multi-step organic synthesis. Amine functions are wildly existed in a great amount of biologically active compounds, making its’ protection a

Restricted access