Regioselective Alkylation of β-Cyclodextrin

1998 ◽  
Vol 51 (10) ◽  
pp. 915 ◽  
Author(s):  
Paramjit S. Bansal ◽  
Craig L. Francis ◽  
Noel K. Hart ◽  
Scott A. Henderson ◽  
David Oakenfull ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Dimethyl Sulfoxide ◽  
Sodium Hydroxide ◽  
Alkyl Halides ◽  
Barium Hydroxide ◽  
Analytical Methodology ◽  
Regioselective Alkylation ◽  
Benzyl Ethers ◽  
Hydroxy Groups

Methodology for preparation of heptakis(2,6-di-O-alkyl)-β-cyclodextrins, heptakis(2-O-alkyl)-β- cyclodextrins, and heptakis(6-O-alkyl)-β-cyclodextrins in substantially purified form has been developed. Treatment of β-cyclodextrin (1) with sodium or barium hydroxide and various alkyl halides in dimethyl sulfoxide or a mixture of dimethyl sulfoxide and N,N-dimethylformamide provided the corresponding heptakis(2,6-di-O-alkyl)-β-cyclodextrins. Treatment of heptakis(6-O-t-butyldimethylsilyl)-β-cyclodextrin (5) with sodium hydroxide and several haloalkanes in dimethyl sulfoxide followed by desilylation provided heptakis(2-O-alkyl)-β-cyclodextrins. Protection of the secondary hydroxy groups of the t-butyldimethylsilyl-β-cyclodextrin (5) as benzyl ethers, followed by desilylation, alkylation, and debenzylation afforded several heptakis(6-O-alkyl)-β-cyclodextrins. Analytical methodology has been developed to characterize all of these compounds, with the homogeneity of the pattern of substitution verified by h.p.l.c. analysis, f.a.b.–mass spectrometry and n.m.r. spectroscopy.

Direct Conversion of Benzyl Ethers into Aryl Nitriles

Synlett ◽  
2018 ◽  
Vol 29 (18) ◽  
pp. 2444-2448 ◽  
Author(s):  
Yun-Lai Ren ◽  
Jianji Wang ◽  
Xinzhe Tian ◽  
Fangping Ren ◽  
Xinqiang Cheng ◽  
...  
Keyword(s):  
Nitrogen Source ◽  
Direct Method ◽  
Direct Conversion ◽  
Aromatic Nitriles ◽  
Organic Syntheses ◽  
Aryl Nitriles ◽  
Benzyl Ethers ◽  
Hydroxy Groups ◽  
A Direct Method

A direct method was developed for the conversion of benzyl ethers into aryl nitriles by using NH4OAc as the nitrogen source and ­oxygen as the terminal oxidant with catalysis by TEMPO/HNO3; the method is valuable for both the synthesis of aromatic nitriles and for the deprotection of ether-protected hydroxy groups to form nitrile groups in multistep organic syntheses.

scholarly journals Kajian Manfaat Senyawa Aktif dalam Ekstrak Kulit Buah Coklat (Theobroma Cacao )

2020 ◽  
Vol 15 (2) ◽  
pp. 13
Author(s):  
Sukatik - ◽  
Rahmi Hidayati ◽  
Roni Tri Putra ◽  
Ratih Paramitha
Keyword(s):  
Mass Spectrometry ◽  
Corrosion Inhibitors ◽  
Condensed Tannin ◽  
Gas Chromatography Mass Spectrometry ◽  
Phytochemical Screening ◽  
Liquid Chromatography Mass Spectrometry ◽  
Active Compounds ◽  
Chromatography Mass Spectrometry ◽  
Polar Extracts ◽  
Hydroxy Groups

Identification of active compounds in cacao pod rind has been done. Cacao pod rind contained active compound alkaloid, theobromine (3,7-dimethylxanthine). Cacao pod rind extract contained some other active compounds mixed flavonoid or condensed tannin such as anthocyanin, anthocyanidin, catechin, epicatechin, epigallocatechin, and leucoanthocyanidin. Cacao pod rind was extracted by maceration using methanol 70% and fractionated with hexane and ethyl acetate to obtain polar extracts. This study used an experimental method that was analyzed descriptively using Gas Chromatography-Mass Spectrometry (GC-MS) and Liquid Chromatography-Mass Spectrometry (LC-MS). Phytochemical screening test showed cocoa pod rind extracts contained alkaloids, flavonoids, tannins, terpenoids, and saponins. GC-MS analysis showed that cacao pod rind extracts contained 24 compounds. Polar extracts analysis with LC-MS obtained 10 compounds contained hydroxy groups, which can be used as corrosion inhibitors on metal. The result of this study showed that cocoa pod rind has potential as corrosion inhibitor. It also has potential as an anti-bacterial and antioxidant.

scholarly journals Diosgenin hemihydrate

2012 ◽  
Vol 68 (8) ◽  
pp. o2357-o2357 ◽  
Author(s):  
María-Guadalupe Hernández Linares ◽  
Sylvain Bernès ◽  
Marcos Flores-Alamo ◽  
Gabriel Guerrero-Luna ◽  
Anselmo A. Martínez-Gallegos
Keyword(s):  
Crystal Structure ◽  
Water Molecule ◽  
Dimethyl Sulfoxide ◽  
Starting Material ◽  
Water Molecules ◽  
Asymmetric Unit ◽  
Acta Cryst ◽  
X Ray ◽  
Hydroxy Groups ◽  
Hydrogen Bonded

Diosgenin [or (22R,25R)-spirost-5-en-3β-ol] is the starting material of the Marker degradation, a cheap semi-synthesis of progesterone, which has been designated as an International Historic Chemical Landmark. Thus far, a single X-ray structure for diosgenin is known, namely its dimethyl sulfoxide solvate [Zhanget al.(2005).Acta Cryst.E61, o2324–o2325]. We have now determined the structure of the hemihydrate, C27H42O3·0.5H2O. The asymmetric unit contains two diosgenin molecules, with quite similar conformations, and one water molecule. Hydroxy groups in steroids and water molecules form O—H...O hydrogen-bondedR54(10) ring motifs. Fused edge-sharingR(10) rings form a backbone oriented along [100], which aggregates the diosgenin molecules in the crystal structure.

Fast Analytical Methodology Based on Mass Spectrometry for the Determination of Volatile Biomarkers in Saliva

2011 ◽  
Vol 84 (1) ◽  
pp. 379-385 ◽  
Author(s):  
Miguel del Nogal Sánchez ◽  
Elena Hernández García ◽  
José Luis Pérez Pavón ◽  
Bernardo Moreno Cordero
Keyword(s):  
Mass Spectrometry ◽  
Analytical Methodology ◽  
Volatile Biomarkers

scholarly journals Quantification of silver nanoparticles taken up by single cells using inductively coupled plasma mass spectrometry in the single cell measurement mode

2018 ◽  
Vol 33 (7) ◽  
pp. 1256-1263 ◽  
Author(s):  
Ana López-Serrano Oliver ◽  
Sabine Baumgart ◽  
Wolfram Bremser ◽  
Sabine Flemig ◽  
Doreen Wittke ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Silver Nanoparticles ◽  
Cell Surface ◽  
Inductively Coupled Plasma ◽  
Single Cells ◽  
Analytical Methodology ◽  
Inductively Coupled ◽  
Cell Measurement ◽  
Measurement Mode ◽  
Plasma Mass Spectrometry

A promising analytical methodology is proposed to study nanoparticle-cell interactions providing information of the number of NPs internalized by cells or externally bound to the cell surface.

An efficient synthesis of 3-alkyl-2-diversity-substituted benzofuro[3,2-d]pyrimidin-4(3H)-one derivatives

2019 ◽  
Vol 43 (5-6) ◽  
pp. 201-204 ◽  
Author(s):  
Hong-Mei Wang ◽  
Tian-Shuai Wang ◽  
Sheng-Jie He ◽  
Zong-Yun Chen ◽  
Yang-Gen Hu
Keyword(s):  
Mass Spectrometry ◽  
Sodium Ethoxide ◽  
Catalytic Amount ◽  
Alkyl Halides ◽  
Efficient Synthesis ◽  
Pyrimidine Derivatives ◽  
Excess Carbon ◽  
H Nmr ◽  
Aliphatic Esters ◽  
C Nmr

Benzofuro[3,2- d]pyrimidine derivatives are prepared using aza-Wittig reactions of iminophosphoranes with n-butyl isocyanate at 40–50 °C to give carbodiimide intermediates, which are reacted with nitrogen-oxygen-containing nucleophiles to give 3-alkyl-2-amino (aryloxy/alkoxy)-benzofuro[3,2- d]pyrimidin-4(3 H)-ones in satisfactory yields in the presence of a catalytic amount of sodium ethoxide or K2CO3. The iminophosphorane also reacts directly with excess carbon disulfide, followed by n-propylamine; further reaction with alkyl halides or halogenated aliphatic esters in the presence of anhydrous K2CO3 produces the corresponding 2-alkylthio-3-n-propyl-benzofuro[3,2- d]pyrimidin-4(3 H)-ones in good yields. Their structures of the products are confirmed by 1H NMR, 13C NMR, mass spectrometry, infrared and elemental analysis.

scholarly journals Determination of Spiroxamine Residues in Grapes, Must, and Wine by Gas Chromatography/Ion Trap-Mass Spectrometry

2005 ◽  
Vol 88 (6) ◽  
pp. 1834-1839 ◽  
Author(s):  
Nicholas G Tsiropoulos ◽  
Konstantinos Liapis ◽  
Dimitrios T Likas ◽  
George E Miliadis
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Ion Trap ◽  
Extraction Procedure ◽  
Ion Trap Mass Spectrometry ◽  
Limit Of Quantification ◽  
Analytical Methodology ◽  
White Wines ◽  
Relative Standard

Abstract Analytical methodology was developed and validated for the determination of spiroxamine residues in grapes, must, and wine by gas chromatography/ion trap-mass spectrometry (GC/IT-MS). Two extraction procedures were used: the first involved grapes, must, and wine extraction with alkaline cyclohexane–dichloromethane (9 + 1, v/v) solution, and the second grape extraction with acetone, dichloromethane, and petroleum ether. In both procedures, the extract was centrifuged, evaporated to dryness, and reconstituted in cyclohexane or 2,2,4-trimethylpentane–toluene (9 + 1, v/v), respectively. Spiroxamine diastereomers A and B were determined by GC/IT-MS, and a matrix effect was observed in the case of grapes but not in must and wine. Recovery of spiroxamine from fortified samples at 0.02 to 5.0 mg/kg ranged from 78–102% for grapes and must, with relative standard deviation (RSD) <13%; for red and white wines, recoveries ranged from 90 to 101% with RSD <9%. The limit of quantification was 0.02 mg/kg for grapes, must, and wine or 0.10 mg/kg for grapes, depending on the extraction procedure used.

scholarly journals In situ Metabolite Mass Spectrometry Imaging: New Insights into the Adrenal Gland

2020 ◽  
Vol 52 (06) ◽  
pp. 435-447
Author(s):  
Fengxia Li ◽  
Annette Feuchtinger ◽  
Axel Walch ◽  
Na Sun
Keyword(s):  
Mass Spectrometry ◽  
Adrenal Gland ◽  
Mass Spectrometry Imaging ◽  
Neuroendocrine Cells ◽  
Adrenal Tumors ◽  
Analytical Methodology ◽  
Formalin Fixed Paraffin ◽  
Formalin Fixed Paraffin Embedded ◽  
Clinically Significant

AbstractThe adrenal gland integrates catecholamine-producing neuroendocrine cells and steroid-producing cells with mesenchymal origin in a structured manner under one capsule and is a key regulator for vital bioactivity. In addition to adrenal-specific disease, dysregulation of adrenal hormones is associated with systemic effects, leading to undesirable metabolic and cardiovascular consequences. Mass spectrometry imaging (MSI) technique can simultaneously measure a broad range of biomolecules, including metabolites and hormones, which has enabled the study of tissue metabolic and hormone alterations in adrenal and adrenal-related diseases. Furthermore, this technique coupled with labeled immunohistochemistry staining has enabled the study of the pathophysiological adaptation of the adrenal gland under normal and abnormal conditions at different molecular levels. This review discusses the recent applications of in situ MSI in the adrenal gland. For example, the combination of formalin-fixed paraffin-embedded tissue microarray and MSI to tissues from patient cohorts has facilitated the discovery of clinically relevant prognostic biomolecules and generated promising hypotheses for new sights into physiology and pathophysiology of adrenal gland. MSI also has enabled the discovery of clinically significant tissue molecular (i. e., biomarker) and pathway changes in adrenal disease, particularly in adrenal tumors. In addition, MSI has advanced the ability to optimally identify and detect adrenal gland specific molecules. Thus, as a novel analytical methodology, MSI has provided unprecedented capabilities for in situ tissue study.

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