Heteroanthracyclines. 2. 4-Demethoxythioxanthodaunomycinone (7,8,9,10-tetrahydrobenzo(b)-6,7,9,11-tetrahydroxy-9-acetylthioxanthen-12-one)

1984 ◽  
Vol 62 (8) ◽  
pp. 1600-1607 ◽  
Author(s):  
Chiu-Ming Wong ◽  
Ai-Qiao Mi ◽  
Jiali Ren ◽  
Wasimul Haque ◽  
Hing-Yat Lam ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Hydrolysis ◽  
Title Compound ◽  
Compound A ◽  
Concentrated Sulfuric Acid

The title compound, a new heteroanthracyclinone was synthesized in five steps starting with 5,8-dimethoxy-2-acetyltetralin (15). Reaction of 2,2′-dithiosalicylic acid (16) with the tetralin 15 in concentrated sulfuric acid gave the tetracyclic thioxanthones 17 and 18. Conversion of 18 to 24 by demethylation and realkylation followed by oxidation and acid hydrolysis gave the title compound 27.

scholarly journals Characteristics of xylose and glucuronic acid at concentrated sulfuric acid hydrolysis

2012 ◽  
Vol 44 (3) ◽  
pp. 9-14 ◽  
Author(s):  
Dae-Haeng Cho ◽  
Yong-Hwan Kim ◽  
Jong-Moon Park ◽  
Jae-Hoon Sim ◽  
Byung-Ro Kim ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Hydrolysis ◽  
Glucuronic Acid ◽  
Concentrated Sulfuric Acid

Gallium Arsenide Integrated Circuits Decapsulation Technique Using Mixed Acid Chemistry For Die-Level Failure Analysis

2018 ◽  
Author(s):  
Harold Jeffrey M. Consigo ◽  
Ricardo S. Calanog ◽  
Melissa O. Caseria
Keyword(s):  
Gallium Arsenide ◽  
Sulfuric Acid ◽  
Nitric Acid ◽  
Integrated Circuits ◽  
Failure Analysis ◽  
Mixed Acid ◽  
Optimum Parameters ◽  
Plastic Package ◽  
Fuming Nitric Acid ◽  
Concentrated Sulfuric Acid

Abstract Gallium Arsenide (GaAs) integrated circuits have become popular these days with superior speed/power products that permit the development of systems that otherwise would have made it impossible or impractical to construct using silicon semiconductors. However, failure analysis remains to be very challenging as GaAs material is easily dissolved when it is reacted with fuming nitric acid used during standard decapsulation process. By utilizing enhanced chemical decapsulation technique with mixture of fuming nitric acid and concentrated sulfuric acid at a low temperature backed with statistical analysis, successful plastic package decapsulation happens to be reproducible mainly for die level failure analysis purposes. The paper aims to develop a chemical decapsulation process with optimum parameters needed to successfully decapsulate plastic molded GaAs integrated circuits for die level failure analysis.

PRODUCTION OF SULFOCATIONITE BY MODIFICATION OF NATURAL COAL WITH CONCENTRATED SULFURIC ACID

2020 ◽  
Vol 3 (441) ◽  
pp. 104-109
Author(s):  
N.A. Bektenov ◽  
◽  
N.C. Murzakassymova ◽  
M.A. Gavrilenko ◽  
А.N. Nurlybayeva ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Concentrated Sulfuric Acid ◽  
Natural Coal

Addition of primary alcohols to 3-chlorononafluoro-1,5-hexadiene and perfluoro-1,3,5-hexatriene

1985 ◽  
Vol 50 (8) ◽  
pp. 1714-1726 ◽  
Author(s):  
Václav Dědek ◽  
Igor Linhart ◽  
Milan Kováč
Keyword(s):  
Sulfuric Acid ◽  
Primary Alcohols ◽  
Principal Product ◽  
Allyl Rearrangement ◽  
Concentrated Sulfuric Acid ◽  
Sodium Alkoxide

Sodium alkoxide-catalyzed addition of methanol, ethanol and propanol to 3-chlorononafluoro-1,5-hexadiene (I) proceeds at temperatures -35 °C to 8 °C with allyl rearrangement, affording 1,6-dialkoxy-1,1,2,3,4,4,5,6,6-octafluoro-2,4-hexadiene (V) as the principal product, along with 1,6-dialkoxy-1,2,3,3,4,5,6,6-octafluoro-1,5-diene (VI) and trans-1,6-dialkoxy-1,1,2,3,4,4,5,6,6-nonafluoro-2-hexene (VII). The ethers Va-Vc consist of the cis,trans- and trans,trans-isomers in about 3 : 1 ratio, whereas the ethers VIa-VIc have trans,trans-configuration. Ethers Vc and VIc react with concentrated sulfuric acid to give dipropyl 2,3,4,5-tetrafluoro-2,4-hexadienedioate (IX) and dipropyl 2,3,4,4,5-pentafluoro-2-hexenedioate (X), respectively, whereas the ether VIIc affords a mixture of propyl 6-propyloxy-2,3,4,4,5,6-heptafluoro-2-hexenoate (XI) and ester X. Addition of methanol to perfluoro-1,3,5-hexatriene (II) affords 1,1,2,3,4,5,6,6-octafluoro-1,6-dimethoxy-3-hexene (XIII) as the principal product.

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