N- and C-Attacks on aromatics of phenylnitrenium ion generated from N-phenylhydroxylamine in the presence of trifluoroacetic acid containing polyphosphoric acid or trifluoroacetic anhydride

2000 ◽  
pp. 295-300 ◽  
Author(s):  
Hiroshi Takeuchi ◽  
Tomohito Taniguchi ◽  
Takahiro Ueda
Keyword(s):  
Trifluoroacetic Acid ◽  
Polyphosphoric Acid ◽  
Trifluoroacetic Anhydride

N,N-Dialkyl-N′-Chlorosulfonyl Chloroformamidines in Heterocyclic Synthesis. Part XIII. Cleavage and Rearrangement Reactions of Pyrazolo[1,5-b][1,2,4,6]thiatriazine 1,1-Dioxides

2016 ◽  
Vol 69 (1) ◽  
pp. 61 ◽  
Author(s):  
Rebecca E. Norman ◽  
Michael V. Perkins ◽  
Andris J. Liepa ◽  
Craig L. Francis
Keyword(s):  
Ethyl Acetate ◽  
Dimethyl Sulfoxide ◽  
Trifluoroacetic Acid ◽  
Sulfonic Acid ◽  
Trifluoroacetic Anhydride ◽  
Ring Cleavage ◽  
Thermal Rearrangement ◽  
Heterocyclic Synthesis ◽  
Similar Treatment ◽  
Catalytic Hydrogenolysis

Treatment of pyrazolo[1,5-b][1,2,4,6]thiatriazines 1 with the Vilsmeier–Haack reagent afforded pyrazolo[1,5-a][1,3,5]triazines 5. Reaction of compounds 1 with trifluoroacetic anhydride, dimethyl sulfoxide, and triethylamine afforded 5-dimethylsulfanylidene derivatives 8. The guanidino-pyrazole-sulfonic acid 9 was produced from treatment of compounds 1 with trifluoroacetic acid under anhydrous conditions. Similar treatment in the presence of water afforded the desulfonated pyrazolo-guanidine 6. Reactions of 6 with one-carbon electrophiles provided various 4-substituted pyrazolo[1,5-a][1,3,5]triazines 5. Attempted catalytic hydrogenolysis of N7-benzyl pyrazolo[1,5-b][1,2,4,6]thiatriazines 2 in alcohols led to sulfamates 12 from thiatriazine ring cleavage. Ethyl acetate or tert-butanol as solvent allowed successful debenzylation to provide compounds 1. Aminolysis of compounds 2 gave sulfamides 13. Thermal rearrangement of compounds 2 afforded 6-benzyl-pyrazolo[3,4-e][1,2,4]thiadiazines 14.

Studies on intramolecular alkylation. X. The acid-catalysed reactions of 5,8-Dialkoxy-1,2,3,4-tetrahydronaphthyl diazomethyl ketones

1978 ◽  
Vol 31 (7) ◽  
pp. 1561 ◽  
Author(s):  
DW Johnson ◽  
LN Mander
Keyword(s):  
Trifluoroacetic Acid ◽  
Acid Treatment ◽  
Polyphosphoric Acid ◽  
Intramolecular Alkylation ◽  
Naphthoic Acid ◽  
Acid Catalysed Reactions ◽  
Diazomethyl Ketones

5,8-Dimethoxy-3,4-dihydronaphthalen-1(2H)-one was converted into diazomethyl 5,8-dimethoxy-1,2,3,4-tetrahydro-2-naphthyl ketone (10) which, when treated with trifluoroacetic acid at 0°, gave 5,8- dimethoxy-4,4a-dihydro-3,4a-ethanonaphthalen-2(3H)-one (13), but at -15° gave 8-methoxy-1,2,3,4-tetrahydro-3,4a-ethanonaphthalene- 5(4aH),10-dione (14). 6-Methoxy-3,4-dihydronaphtha-len-1(2H)-one reacted with m-chloroperoxybenzoic acid to give 4,5-dihydro-1-benzoxepin-2(3H)-one (15) which after hydrolysis, ethylation and polyphosphoric acid treatment gave 5-ethoxy-8-methoxy-3,4-dihydronaphthalen-1(2H)-one (17). This compound was transformed into 5-ethoxy-8-hydroxy-1,2,3,4-tetrahydro-2-naphthoic acid (19) and thence to the ethoxy analogue of (14).

Clean-Chemistry Sulfonation of Aromatics

2002 ◽  
Vol 2002 (7) ◽  
pp. 326-327 ◽  
Author(s):  
Brian W. Corby ◽  
Anthony D. Gray ◽  
Padraig J. Meaney ◽  
Michael J. Falvey ◽  
Gregory P. Lawrence ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Trifluoroacetic Acid ◽  
Trifluoroacetic Anhydride ◽  
Phase System

A solution of TFAA/H2SO4 is an atom-efficient liquid-phase system for rapid sulfonation of aromatic structures; H2SO4 is consumed stoichiometrically and the spent trifluoroacetic anhydride (TFAA) is readily recovered as trifluoroacetic acid (TFA) which can be recycled to TFAA.

Synthesis of 1,1,5,6-Tetramethyl- and 7-Isopropyl-1,1-dimethyl-1,2,3,4-tetrahydronaphthalene

1999 ◽  
Vol 64 (3) ◽  
pp. 527-532 ◽  
Author(s):  
Ramchandra Bhimrao Mane ◽  
Abhijit Jaysingrao Kadam ◽  
Rajashree Sandeep Salunkhe
Keyword(s):  
Trifluoroacetic Acid ◽  
Polyphosphoric Acid ◽  
Titanium Tetrachloride ◽  
Grignard Reaction ◽  
Butanoic Acid ◽  
Methylmagnesium Iodide

4-(2,3-Dimethylphenyl)butanoic acid (4) was treated with excess of methyllithium to yield 5-(2,3-dimethylphenyl)-2-methylpentan-2-ol (6) which was cyclodehydrated using Dowex 50W-X8 resin, trifluoroacetic acid or polyphosphoric acid (PPA) to furnish 1,1,5,6-tetramethyl-1,2,3,4-tetrahydronaphthalene (1). The acid 4 was cyclized with PPA to furnish 5,6-dimethyl-3,4-dihydronaphthalen-1(2H)-one (5) which was converted into 1 by reaction with dimethylzinc and titanium tetrachloride. 4-(4-Isopropylphenyl)butanoic acid (7) on esterification followed by Grignard reaction with methylmagnesium iodide furnished 5-(4-isopropylphenyl)-2-methylpentan-2-ol (9), which was cyclodehydrated as above to yield 7-isopropyl-1,1-dimethyl-1,2,3,4-tetrahydronaphthalene (2).

Ipso nitration. XVIII. Nitrationof 2-chloro-1,3,5-trimethylbenzene: nitration ipso to chlorine

1978 ◽  
Vol 56 (10) ◽  
pp. 1348-1357 ◽  
Author(s):  
Alfred Fischer ◽  
Sachdev Singh Seyan
Keyword(s):  
Acetic Acid ◽  
Ambient Temperature ◽  
Trifluoroacetic Acid ◽  
Boron Trifluoride ◽  
Boron Trifluoride Etherate ◽  
Trifluoroacetic Anhydride ◽  
Trans Isomers ◽  
Dimethyl Benzyl ◽  
Cis And Trans Isomers ◽  
Cis And Trans

Nitration of 2-chloro-1,3,5-trimethylbenzene in acetic anhydride gives the cis and trans isomers of 4-chloro-1,3,5-trimethyl-4-nitrocyclohexa-2,5-dienyl acetate (1, 21%), the cis and trans isomers of 3-chloro-2,4,6-trimethyl-4-nitrocyclohexa-2,5-dienyl acetate (2, 6%), and 2-chloro-1,3,5-trimethyl-4-nitrobenzene (73%). Diene 1 reacts with acidified aqueous acetone to form the corresponding dienol, acidified methanol to form the methyl ether, and hydrogen chloride to form the corresponding chloride. In acetic acid a mixture of 4-chloro-3,5-dimethyl-benzyl derivatives and 3-chloro-2,4,6-trimethylphenyl acetate are formed. In trifluoroacetic acid – trifluoroacetic anhydride and also in boron trifluoride etherate, 2-chloro-1,3,5-trimethyl-4-nitrobenzene is the predominant product. Diene 2 on reaction with acetic acid, acidified methanol, trifluoroacetic acid – trifluoroacetic anhydride, and boron trifluoride etherate gives 3-chloro-2,4,6-trimethylphenyl acetate. Some 2-chloro-4-nitromesitylene is obtained in trifluoromethanesulfonic acid. Diene 2 also gives the acetate on standing at ambient temperature or at −20 °C, and on pyrolysis. Diene 1 gives 4-chloro-3,5-dimethylphenylnitromethane on standing at ambient temperature or at −20 °C but a mixture of 2-chloro-1,3,5-trimethyl-4-nitrobenzene, chloromesitylene, and 3-chloro-2,4,6-trimethylphenyl acetate on pyrolysis.

THE NUCLEAR MAGNETIC RESONANCE SPECTRA OF TRIARYL CARBONIUM IONS

1959 ◽  
Vol 37 (9) ◽  
pp. 1402-1408 ◽  
Author(s):  
R. B. Moodie ◽  
T. M. Connor ◽  
Ross Stewart
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Trifluoroacetic Acid ◽  
Chemical Shifts ◽  
Trifluoroacetic Anhydride ◽  
Para Position ◽  
Single Peak ◽  
Carbonium Ions ◽  
Nuclear Magnetic Resonance Spectra ◽  
Neutral Compounds

The N.M.R. spectra of the triphenylmethyl cation and several of its derivatives substituted with methyl, methoxyl, and tert-butyl groups in the meta or para position have been obtained in trifluoroacetic acid – trifluoroacetic anhydride solution. The ring protons and substituent protons are all shifted to lower fields, i.e. are less shielded in the carbonium ions than in the neutral compounds of similar structure. The chemical shifts for the substituent protons are greater for para than for meta substituents and for mono- rather than tri-substituted ions. With each ion only a single peak was observed for the substituent protons but the ring protons were, in some cases, well resolved. The theoretical implications of these results are discussed.

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