Anthracyclines. XI. A short, site-specific synthesis of unsymmetrical 3-Acetyl-5,8-dialkoxy-1,2-dihydronaphthalenes; key precursors to daunomycinone AB-synthons

1984 ◽  
Vol 37 (8) ◽  
pp. 1721 ◽  
Author(s):  
RA Russell ◽  
GJ Collin ◽  
MP Crane ◽  
PS Gee ◽  
AS Krauss ◽  
...  
Keyword(s):  
Acetyl Chloride ◽  
Cost Effective ◽  
Base Hydrolysis ◽  
Chromatographic Separations ◽  
Phenol Alkylation ◽  
Site Specific ◽  
Effective Synthesis ◽  
Hydrolysis Of ◽  
Specific Synthesis

5,8-Dihydronaphthalene-1,4-diol, readily available from benzoquinone and buta-1,3-diene, is isomerized by heating with strong sodium hydroxide, and acetylated (Ac2O), in situ, to form 5,8-diacetoxy-1,2-dihydronaphthalene. Catalysed (AlCl3) addition of acetyl chloride followed by dehydrochlorination (LiCI/HCONMe2) yielded 5,8-diacetoxy-3-acetyl-1,2-dihydronaphthalene (11) in 82% overall yield. Base hydrolysis of (11), followed by methylation (Me2SO4) gives 3-acetyl-5,8-dimethoxy-1,2-dihydronaphthalene in 94% yield, the most direct route to this product so far described. More importantly, the diacetate (11) is selectively deacetylated at C5 (Cs2CO3 in tetrahydrofuran, or K2CO3 in Me2SO) to form the related phenol, alkylation of which produces the 5-alkoxy compound. Further hydrolysis followed by alkylation yields the unsymmetrically, but regiospecifically substituted, 3-acetyl-5,8-dialkoxy-1,2-dihydronaphthalenes. This method is specifically illustrated by the production of 3-acetyl-5-benzyloxy-8-methoxy-1,2-dihydronaphthalene which is formed in a short, cost effective synthesis in a moderate overall yield (25%) based upon benzoquinone as starting material;significantly, no chromatographic separations are required.

Squaraine chemistry. A new approach to symmetrical and unsymmetrical photoconductive squaraines. Characterization and solid state properties of these materials

1993 ◽  
Vol 71 (4) ◽  
pp. 494-505 ◽  
Author(s):  
Kock-Yee Law ◽  
F. Court Bailey
Keyword(s):  
Solid State ◽  
Condensation Reaction ◽  
Cost Effective ◽  
Squaric Acid ◽  
Reductive Alkylation ◽  
Reaction Sequence ◽  
New Approach ◽  
Effective Synthesis ◽  
Better Than

A new approach to 1-(p-dimethylaminophenyl)-2-hydroxycyclobutene-3,4-dione (4), a precursor for the synthesis of symmetrical and unsymmetrical photoconductive squaraines, is described. In situ generation of p-nitrophenyl ketene, by the reaction of p-nitrophenylacetyl chloride and triethylamine in the presence of tetraethoxyethylene in anhydrous ether, results in a (2 + 2) cycloaddition between the ketene and the electron-rich olefin. The cycloadduct generated, 6, was hydrolyzed to give 1-(p-nitrophenyl)-2-hydroxycyclobutene-3,4-dione (5) in 51% yield. Reductive alkylation of 5 by hydrogen in the presence of formaldehyde in DMF at 50–60 °C affords 4 in 81% yield. The overall yield of 4 is 41% from tetraethoxyethylene and is significantly better than other preparative procedures of 4 based on a partial Friedel–Crafts reaction or an arylation reaction of a squaric acid derivative with an aniline, where yields ranging from 8.5% to 24% were reported. Condensations of 4 with 2 equivalents of N,N-dimethylaniline and its derivatives in refluxing 2-propanol in the presence of 6 equivalents of tributyl orthoformate yield symmetrical squaraine 1a and unsymmetrical squaraines 1b–1e. The synthesis is accomplished by a (2 + 2) cycloaddition – reductive alkylation – condensation reaction sequence and represents a new, cost-effective synthesis for photoconductive squaraines where the expensive squaric acid reactant is bypassed. The spectroscopic and the solid state properties of 1a–1e have been studied. Results show that the properties exhibited by 1a–1e are essentially identical to those exhibited by other photoconductive, symmetrical squaraines that are synthesized by other known processes. From the resemblance in solid state properties, 1a–1e are expected to be photoconductive. This has indeed been observed in preliminary experiments.

Site-Specific Synthesis and In Situ Immobilization of Fluorescent Silver Nanoclusters on DNA Nanoscaffolds by Use of the Tollens Reaction

2011 ◽  
Vol 123 (18) ◽  
pp. 4262-4265 ◽  
Author(s):  
Suchetan Pal ◽  
Reji Varghese ◽  
Zhengtao Deng ◽  
Zhao Zhao ◽  
Ashok Kumar ◽  
...  
Keyword(s):  
Silver Nanoclusters ◽  
In Situ Immobilization ◽  
Site Specific ◽  
Specific Synthesis

In-situ Formation of Co3O4 Nanocrystals Embedded in Laser-Induced Graphene Foam for High-Energy Flexible Micro-supercapacitor

2022 ◽  
Author(s):  
Xiaohong Ding ◽  
Ruilai Liu ◽  
Jiapeng Hu ◽  
Jingyun Zhao ◽  
Jinjin Wu ◽  
...  
Keyword(s):  
Cost Effective ◽  
High Energy ◽  
Wearable Electronics ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Effective Synthesis ◽  
In Situ Formation ◽  
The Cost ◽  
Power Densities

The cost-effective synthesis of flexible energy storage devices with high energy and power densities is a challenge in wearable electronics. Here, we report a facile, efficient, and scalable approach for...

scholarly journals A Cost-Effective and Eco-Friendly Way to Dihydroxylate Terminal and Internal Alkenes Using Hydrogen Peroxide/formic Acid

2020 ◽  
Author(s):  
Chia-Wei Hsu ◽  
Trevor Dzwiniel ◽  
Krzysztof Pupek
Keyword(s):  
Hydrogen Peroxide ◽  
Formic Acid ◽  
Cost Effective ◽  
Performic Acid ◽  
Excess Water ◽  
Hydrolysis Of

<div> <p>Abstract In this report, we present a modified dihydroxylation procedure for terminal and internal alkenes under neat conditions using formic acid and hydrogen peroxide. Upon the <i>in situ</i> formation of performic acid, followed by the hydrolysis of hydroxy-formoxy compounds with excess water, we can obtain a series of diols without catalysts and bases.</p> </div>

In-situ cost-effective synthesis of zeolite A in Al2O3–SiO2 glass fibers for fixed bed adsorption of Cu2+, Cd2+ and Pb2+

Adsorption ◽  
2021 ◽  
Author(s):  
Antonia M. M. França ◽  
Raquel A. Bessa ◽  
Edipo S. Oliveira ◽  
Marcos V. M. Nascimento ◽  
Francisco M. T. Luna ◽  
...  
Keyword(s):  
Glass Fibers ◽  
Fixed Bed ◽  
Cost Effective ◽  
Zeolite A ◽  
Sio2 Glass ◽  
Fixed Bed Adsorption ◽  
Effective Synthesis

Site-Specific Synthesis and In Situ Immobilization of Fluorescent Silver Nanoclusters on DNA Nanoscaffolds by Use of the Tollens Reaction

2011 ◽  
Vol 50 (18) ◽  
pp. 4176-4179 ◽  
Author(s):  
Suchetan Pal ◽  
Reji Varghese ◽  
Zhengtao Deng ◽  
Zhao Zhao ◽  
Ashok Kumar ◽  
...  
Keyword(s):  
Silver Nanoclusters ◽  
In Situ Immobilization ◽  
Site Specific ◽  
Specific Synthesis

scholarly journals A Cost-Effective and Eco-Friendly Way to Dihydroxylate Terminal and Internal Alkenes Using Hydrogen Peroxide/formic Acid

2020 ◽  
Author(s):  
Chia-Wei Hsu ◽  
Trevor Dzwiniel ◽  
Krzysztof Pupek
Keyword(s):  
Hydrogen Peroxide ◽  
Formic Acid ◽  
Cost Effective ◽  
Performic Acid ◽  
Excess Water ◽  
Hydrolysis Of

<div> <p>Abstract In this report, we present a modified dihydroxylation procedure for terminal and internal alkenes under neat conditions using formic acid and hydrogen peroxide. Upon the <i>in situ</i> formation of performic acid, followed by the hydrolysis of hydroxy-formoxy compounds with excess water, we can obtain a series of diols without catalysts and bases.</p> </div>

scholarly journals A Cost-Effective and Eco-Friendly Way to Dihydroxylate Terminal and Internal Alkenes Using Hydrogen Peroxide/formic Acid

2020 ◽  
Author(s):  
Chia-Wei Hsu ◽  
Trevor Dzwiniel ◽  
Krzysztof Pupek
Keyword(s):  
Hydrogen Peroxide ◽  
Formic Acid ◽  
Cost Effective ◽  
Performic Acid ◽  
Excess Water ◽  
Hydrolysis Of

<div> <p>Abstract In this report, we present a modified dihydroxylation procedure for terminal and internal alkenes under neat conditions using formic acid and hydrogen peroxide. Upon the <i>in situ</i> formation of performic acid, followed by the hydrolysis of hydroxy-formoxy compounds with excess water, we can obtain a series of diols without catalysts and bases.</p> </div>

INDIREKTE PAPIERCHROMATOGRAPHISCHE METHODE ZUR BESTIMMUNG DER HARNOESTROGENE

1961 ◽  
Vol 38 (4) ◽  
pp. 545-562 ◽  
Author(s):  
L. Kecskés ◽  
F. Mutschler ◽  
I. Glós ◽  
E. Thán ◽  
I. Farkas ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Granulosa Cell ◽  
Iron Content ◽  
List Type ◽  
Granulosa Cell Tumour ◽  
Hydrolysis Of ◽  
Phenol Fraction ◽  
Qualitative Determination

ABSTRACT 1. An indirect paperchromatographic method is described for separating urinary oestrogens; this consists of the following steps: acidic hydrolysis, extraction with ether, dissociation of phenol-fractions with partition between the solvents. Previous purification of phenol fraction with the aid of paperchromatography. The elution of oestrogen containing fractions is followed by acetylation. Oestrogen acetate is isolated by re-chromatography. The chromatogram was developed after hydrolysis of the oestrogens 'in situ' on the paper. The quantity of oestrogens was determined indirectly, by means of an iron-reaction, after the elution of the iron content of the oestrogen spot, which was developed by the Jellinek-reaction. 2. The method described above is satisfactory for determining urinary oestrogen, 17β-oestradiol and oestriol, but could include 16-epioestriol and other oestrogenic metabolites. 3. The sensitivity of the method is 1.3–1.6 μg/24 hours. 4. The quantitative and qualitative determination of urinary oestrogens with the above mentioned method was performed in 50 pregnant and 9 non pregnant women, and also in 2 patients with granulosa cell tumour.

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