Acid-catalyzed rearrangement of cyclobutanones. V. Preparation of polycyclic aromatic dihydrofurans and dihydropyrans

1980 ◽  
Vol 58 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Paul Duperrouzel ◽  
Edward Lee-Ruff
Keyword(s):  
Polycyclic Aromatic ◽  
Acidic Conditions ◽  
Acid Catalyzed

Cyclobutanones derived from α-phenyl, α,α-diphenyl, and bisphenyleneketene cycloaddition to dihydrofuran and dihydropyran were rearranged under acidic conditions to polycyclic aromatic dihydrofurans and dihydropyrans respectively. A mechanism for these rearrangements is proposed.

The acid-catalyzed oxido-reduction of spiroketals. Evidence for stereoelectronic control in hydride transfer to cyclic oxenium ions

1981 ◽  
Vol 59 (18) ◽  
pp. 2787-2802 ◽  
Author(s):  
Pierre Deslongchamps ◽  
Daryl D. Rowan ◽  
Normand Pothier
Keyword(s):  
Hydride Transfer ◽  
Reduction Reaction ◽  
Sodium Cyanoborohydride ◽  
Oxidation Reduction ◽  
Oxidation Reduction Reaction ◽  
Stereoelectronic Control ◽  
Acidic Conditions ◽  
Acid Catalyzed ◽  
Ether Ketone ◽  
Catalyzed Oxidation

Tricyclic spiroketal 1 undergoes an acid-catalyzed oxidation–reduction reaction which yields equatorial bicyclic ether aldehyde 5 specifically. Similarly, spiroketals 2, 3, and 4 give equatorial bicyclic ether ketone 12. These results are interpreted by invoking an internal hydride transfer from an alcohol function to a cyclic oxenium ion which takes place with stereoelectronic control. The reduction of tricyclic ketals 1 and 22 with sodium cyanoborohydride under acidic conditions is also reported.

The bromination and chlorination of 2,3-dialkylindoles. Isolation of 3-bromo- and 3-chloro-2,3-dialkylindolenines and acid catalyzed conversion to 3-methoxyindolenines

1980 ◽  
Vol 58 (8) ◽  
pp. 808-814 ◽  
Author(s):  
Gary I. Dmitrienko ◽  
Edward A. Gross ◽  
Susan F. Vice
Keyword(s):  
Acetic Acid ◽  
Good Yield ◽  
Room Temperature ◽  
Chemical Properties ◽  
Nitrogen Atmosphere ◽  
Crystalline Solid ◽  
Tert Butyl ◽  
Acidic Conditions ◽  
Acid Catalyzed

The bromination of 2,3-dimethylindole in acetic acid followed by hydrolysis has been shown to yield the known dimer 16 of 3-hydroxy-2,3-dimethylindolenine 15 and not 3-hydroxymethyl-2-methylindole 12 as reported previously by others. Bromination of 2,3-dimethylindole in the presence of triethylamine has yielded 3-bromo-2,3-dimethylindolenine 17 as a crystalline solid which is stable at room temperature in a nitrogen atmosphere in the presence of triethylamine but decomposes vigorously in the absence of base. Under mildly acidic conditions 17 reacts rapidly with methanol to yield 3-methoxy-2,3-dimethylindolenine 3 in good yield. With tert-butyl hypochlorite in the presence of triethylamine, 2,3-dimethylindole gives 3-chloro-2,3-dimethylindolenine 2 which has chemical properties similar to 17 reacting readily with methanol to give 3. Similarly tetrahydrocarbazole was converted to the analogous chloroindolenine 5 and bromoindolenine 18 both of which readily underwent methanolysis to give 6 in good yield. A mechanism for the acid catalyzed methanolysis of 3-chloro- and 3-bromoindolenines is proposed.

Synthetic Entry to Tricyclic and Tetracyclic Quinuclidine Derivatives by Cycloaddition and Ring Transformation

2006 ◽  
Vol 61 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Wafaa S. Hamama ◽  
Osama M. Abd El-Magid ◽  
Hanafi H. Zoorob
Keyword(s):  
Antibacterial Activities ◽  
Ring Transformation ◽  
Fused Heterocycles ◽  
Heterocyclic Derivatives ◽  
Tetracyclic System ◽  
Acidic Conditions ◽  
Acid Catalyzed

The (Z)-2-arylidene-quinuclidines 5 - 8 were synthesized. Their reaction with aliphatic dibasic functional reagents in both basic and acidic conditions afforded the fused heterocycles 9, 10 and 11. However, the reaction of arylidene derivative 5 with an aromatic dibasic functional reagent gave benzimidazole 13 in lieu of the anticipated tetracyclic system, quinuclidino[3,2-e]benzo[b]-1,4-diazepine 12. Cycloadditions of 5 with different reagents gave the heterocyclic derivatives 17, 19, 22 and 23. Acid-catalyzed cyclization of 5 with excess resorcinol gave 24. Compounds 9a, 19 and 24 showed antibacterial activities.

Acid-Catalyzed Intramolecular Ring-Opening Reactions of Cyclopropanated Oxabenzonorbornadienes with Carboxylic Acid Nucleophiles

Synthesis ◽  
2021 ◽  
Author(s):  
Angel Ho ◽  
Austin Pounder ◽  
Samuel Koh ◽  
Matthew Macleod ◽  
Emily Carlson ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Ring Opening ◽  
Reaction Conditions ◽  
Ring Opening Reactions ◽  
Acidic Conditions ◽  
Acid Catalyzed ◽  
Type 3 ◽  
Intramolecular Ring

The present work demonstrates the ability of carboxylic acid-tethered cyclopropanated oxabenzonorbornadienes (CPOBDs) to undergo ring-opening reactions in mild acidic conditions. The optimized reaction conditions involve the use of pTsOH in DCE at 90 °C. Two regioisomers are formed but the reactions are highly regioselective towards type 3 ring-opened products. It was observed that substitution at the C-5 and aryl positions of CPOBD significantly hinders the ring opening reactions leading to decreased yields of ring-opened product, although high regioselectivity for the Type 3 ring-opened product is still maintained. Herein, we report the first examples of acid-catalyzed intramolecular ring-opening reactions of CPOBD with carboxylic acid nucleophiles.

Transmission infrared study of acid-catalyzed sol-gel silica coatings during room ambient drying

1992 ◽  
Vol 7 (8) ◽  
pp. 2230-2239 ◽  
Author(s):  
T.M. Parrill
Keyword(s):  
Thin Films ◽  
Fourier Transform ◽  
Infrared Spectra ◽  
Spin Coating ◽  
Room Temperature ◽  
Sol Gel ◽  
Infrared Study ◽  
Silica Coatings ◽  
Acidic Conditions ◽  
Acid Catalyzed

Sol-gel solutions prepared from tetraethylorthosilicate (TEOS) hydrolyzed in acidic conditions were used to make thin films on Si wafers via spin coating. Solutions with H2O/TEOS ratios of 2, 5, and 10 were prepared and aged at room temperature in sealed containers for times ranging from <2.5 h to 1 month. Transmission Fourier transform infrared spectra acquired around 1 min after spinning showed peaks characteristic of both SiO2 and SiOH. Additional features at ≍580, 1093, and 1130 cm−1 were observed and possible origins are discussed. Peaks at ≍580 and 1130 cm−1, which increased in intensity with solution age time, are attributed to cyclic Si–O, e.g., 4-member rings. When films were exposed to room air, ring concentration decreased significantly within 30 min. Rings were stable for hours, however, when films were kept in N2. The feature at 1093 cm−1, most sensitive to H2O/TEOS, is attributed to residual Si–O–C.

The Wallach rearrangement. Part V. Acid catalyzed hydrolysis of azobenzene-4-hydrogen sulfate

1969 ◽  
Vol 47 (6) ◽  
pp. 911-917 ◽  
Author(s):  
E. Buncel ◽  
W. M. J. Strachan
Keyword(s):  
Potassium Salt ◽  
Reactive Species ◽  
Acidity Function ◽  
Hydrogen Sulfate ◽  
Sulfate Salt ◽  
Acid Media ◽  
Phenolic Oxygen ◽  
Acidic Conditions ◽  
Acid Catalyzed ◽  
Hydrolysis Of

In relation to the intermediacy of azobenzene-4-hydrogen sulfate in the Wallach rearrangement of azoxybenzene, the potassium salt has been characterized and subjected to examination under acidic conditions. A pKa value of −2.14 has been obtained, for N-protonation. The sulfate salt hydrolyzes to p-hydroxyazobenzene in acid media and the rate of the reaction has been measured over the region 22–42% H2SO4 at 25° spectrophotometrically. A correlation between rate and acidity function indicates that a two-proton process is involved; a reactive species is proposed having a nitrogen and the phenolic oxygen protonated. The relevance of these findings to Wallach rearrangement studies is discussed.

Acid-catalyzed Photocycloaddition of 6-Chloro-1,3-dimethyluracil to Polycyclic Aromatic Hydrocarbons

Heterocycles ◽  
2003 ◽  
Vol 59 (2) ◽  
pp. 459 ◽  
Author(s):  
Koh-ichi Seki ◽  
Kazue Ohkura ◽  
Shun Uchiyama ◽  
Masayuki Sato ◽  
James M. Diakur
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Polycyclic Aromatic ◽  
Acid Catalyzed
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