Acid-catalyzed rearrangement of 3-carene-2,5-dione (3,7,7-trimethylbicyclo[4.1.0]hept-3-ene-2,5-dione)

1970 ◽  
Vol 48 (6) ◽  
pp. 1013-1016 ◽  
Author(s):  
I. W. J. Still ◽  
G. W. Nathan
Keyword(s):  
Sulfuric Acid ◽  
Acetic Anhydride ◽  
Concentrated Sulfuric Acid ◽  
Acid Catalyzed

The reaction of 3-carene-2,5-dione (2) with acetic anhydride–concentrated sulfuric acid at 25° has been shown to lead exclusively to the formation of 2-methyl-6-isopropenylhydroquinone diacetate (3b).

Cyclodiene Chemistry. III. Derivative Formation for the Identification of Heptachlor, Heptachlor Epoxide, cis-Chlordane, irans-Chlordane, Dieldrin, and Chromatography

1969 ◽  
Vol 52 (6) ◽  
pp. 1220-1226 ◽  
Author(s):  
Alfred S Y Chau ◽  
W P Cochrane
Keyword(s):  
Sulfuric Acid ◽  
Acid Treatment ◽  
Heptachlor Epoxide ◽  
Improved Method ◽  
Sulfuric Acid Treatment ◽  
Subsequent Conversion ◽  
Concentrated Sulfuric Acid ◽  
Acid Catalyzed ◽  
Cis And Trans ◽  
Feed Samples

Abstract An improved method, involving potassium tert.-butoxide and tert.-butanol treatment followed by acetylation, is described for the similtaneous confirmation of heptachlor, heptachlor epoxide, and cis- and trans-chlordanes in cleaned-up feed samples. Parent pesticide residues can be identified at levels of 0.01 ppm and above. As a confirmative test for dieldrin, the formation of an acetate and subsequent conversion to a “ketone” by acetic anhydride/ sulfuric acid treatment is used. The concentrated sulfuric acid-catalyzed isomerization of endrin is also reported.

The Nitration of Some 4-Alkylphenols; Acid-Catalyzed Rearrangements of Some Polysubstituted 4-Alkyl-4-Hydroxycyclohexa-2,5-Dienones

1986 ◽  
Vol 39 (1) ◽  
pp. 59 ◽  
Author(s):  
MJ Gray ◽  
MP Hartshorn ◽  
J Vaughan
Keyword(s):  
Sulfuric Acid ◽  
Alkyl Group ◽  
Concentrated Sulfuric Acid ◽  
Acid Catalyzed

The nitrations of 4-methyl (6a) and 4-ethyl (9a) tetrabromo phenols, and 4-methyl (6b) and 4-ethyl (9b) 2,3,5-tribromo-6-nitrophenols are described. The acid- catalysed rearrangements of 4-alkyl-4-hydroxycyclohexa-2,5-dienones (7a,b) and (8a,b) in concentrated sulfuric acid are described, and the effects of the nature of the C4- alkyl group and C6-substituent (Br or NO2) on the observed reactions are discussed.

ChemInform Abstract: Nitration of Anilinium Ions in Concentrated Sulfuric Acid Catalyzed by Nitrosonium Hydrogensulfate.

ChemInform ◽  
2010 ◽  
Vol 27 (2) ◽  
pp. no-no
Author(s):  
M. V. GORELIK ◽  
V. I. LOMZAKOVA ◽  
E. A. KHAMIDOVA ◽  
V. YA. SHTEIMAN ◽  
M. G. KUZNETSOVA
Keyword(s):  
Sulfuric Acid ◽  
Concentrated Sulfuric Acid ◽  
Acid Catalyzed

scholarly journals Rearrangements in the acid-catalyzed formation of lactones from 2-hydroxynorbornane-2-acetic acid derivatives and related compounds

1992 ◽  
Vol 70 (9) ◽  
pp. 2491-2501 ◽  
Author(s):  
Peter Yates ◽  
Magdy Kaldas
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Ethyl Esters ◽  
Alkyl Groups ◽  
Acid Lactone ◽  
Concentrated Sulfuric Acid ◽  
Acid Catalyzed ◽  
Preliminary Study ◽  
Related Compounds ◽  
Acetic Acids

A mixture of the epimeric ethyl 2-hydroxynorbornane-2-acetates (1) on treatment with concentrated sulfuric acid is converted in turn to the lactones of exo-2-hydroxynorbornane-1-acetic acid (4), endo-6-hydroxynorbornane-endo-2-acetic acid (5), and exo-3-hydroxynorbornane-exo-2-acetic acid (6). With trifluoroacetic acid or 50% sulfuric acid, 1 gives 4, but this does not react further. In concentrated sulfuric acid the parent acids of 1 (7) and (E)- and (Z)-(norborn-2-ylidene)acetic acids (8 and 9) and their ethyl esters (10 and 11) give 6 as the infinity product. A mixture of 5-norbornene-endo- and exo-2-acetic acid (30 and 31) on treatment with 50% sulfuric acid gives 4, 5, 6, and exo-2-hydroxynorbornane-syn-7-acetic acid lactone (33). Routes are proposed for the formation of the lactones that involve protonation and carbocation formation followed by rearrangement via Wagner–Meerwein, endo-6,2-hydride, and exo-3,2-hydride shifts in decreasing order of preference. It is postulated that the usual inhibition of the rearrangement of tertiary to secondary norbornyl carbocations is not operative when the third substituent is a carboxymethyl group or its derivatives because of the electron-withdrawing properties of such groups relative to simple alkyl groups. A preliminary study has shown that exo-5-acetyloxy-endo-2-hydroxynorbornane-exo-2-acetic acid (35) with 50% sulfuric acid gives four products that are considered to be the γ-lactones of endo-5-acetyloxy- and endo-5-hydroxynorbornane-1-acetic acid (38 and 39) and exo-2-acetyloxy-1-hydroxy-and 1,2-dihydroxynorbornane-syn-7-acetic acid (40 and 41). Protonation of either the hydroxyl or acetyloxyl group is postulated, giving two carbocations that undergo rearrangements as in the case of 1, together with 3,2-hydroxyl shifts. The structures of the lactones are assigned on the basis of spectroscopy, reactivity, and analogy. The reactions of the lactones, which lead to a variety of hydroxy- and oxonorbornaneacetic acids, illustrate their synthetic potential.

Modified Synthesis of 2-Ethoxycarbonyl-3,4-Diethyl-Pyrrole and the Corresponding Octaethylporphyrin

2014 ◽  
Vol 884-885 ◽  
pp. 465-470
Author(s):  
Qi Feng Liu
Keyword(s):  
Sulfuric Acid ◽  
Low Temperature ◽  
Acetic Anhydride ◽  
Acetyl Chloride ◽  
Toluene Solution ◽  
Organic Base ◽  
Crude Product ◽  
Concentrated Sulfuric Acid ◽  
Boiling Toluene

In the synthesis of 2-ethoxycarbonyl-3, 4-diethyl-pyrrole (1) by the Barton-Zard reaction of 4-acetoxy-3-nitrohexane (1b) with ethyl isocyanoacetate, the organic base 1, 8-diazabicyclo [5.4.0] undec-7-ene (DBU) and the solvent tetrahydrofuran (THF) were replaced with K2CO3 and ethanol, respectively. Moreover, the preparation of the intermediate 1b from 1a by acetylation reaction was carried out by employing acetyl chloride in boiling toluene solution instead of acetic anhydride and the catalyst concentrated sulfuric acid. After treatment of 1 with excess LiAlH4 at low temperature, the crude product 1c (α-hydroxymethyl-3, 4-diethyl-pyrrole) was immediately reacted via a tetramerization in the presence of the catalyst BF3.OEt2 in crude CHCl3,followed by oxidation of 2, 3-dichloro-5, 6-dicyano-1, 4-benzoquinone (DDQ) to provide the corresponding octaethylporphyrin 2. The results indicate that using BF3.OEt2 as catalyst instead of p-toluenesulphonic acid (p-TsOH)in the synthesis of 2 from 1c can obviously increase the yield of product 2 up to 80% from 69%.

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

An Expedient Approach to the Synthesis of Chloroacetic, Dichloroacetic and Acetic Acid Catalyzed by Sulfuric Acid in the Presence of Crown Ethers

2006 ◽  
Vol 3 (12) ◽  
pp. 940-942 ◽  
Author(s):  
Shahnaz Perveen ◽  
Tahira Sarfaraz ◽  
Khalid Khan ◽  
Wolfgang Voelter
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Crown Ethers ◽  
Acid Catalyzed

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.

Sign in / Sign up

Export Citation Format

Share Document