Nitration of 2,3,4,6-Tetramethylphenol and 1,2,3,5-Tetramethylbenzene

1985 ◽  
Vol 38 (4) ◽  
pp. 587 ◽  
Author(s):  
MP Hartshorn ◽  
JM Readman ◽  
WT Robinson ◽  
J Vaughan

Nitration of 1,2,3,5-tetramethylbenzene (2a) with fuming nitric acid gives the tetramethylnitrobenzene (22), products of side-chain modification (23)-(27), the rearranged 6,6-dimethylcyclohexenones (8), (28), (29) and (30), and 2,3,4,6-tetramethyl ketone derivatives (10)- (13), (31) and (32). Reaction of 2,3,4,6-tetramethylphenol (7) with nitrogen dioxide gives the hydroxy dinitro ketone (9) in addition to the trinitrocyclohexenones (11)-(14) and (19). X-ray crystal structures are reported for compounds (11), (19), (28), (29), (30) and (32). 1H n.m.r ./stereochemistry correlations are reported for some 2,5-dinitro- and 2,5,6-trinitro-cyclohex-3-enones.

1984 ◽  
Vol 37 (7) ◽  
pp. 1489 ◽  
Author(s):  
MP Hartshorn ◽  
WT Robinson ◽  
J Vaughan ◽  
JM White ◽  
AR Whyte

Nitration of pentamethylphenol (1) with nitrogen dioxide in benzene gives the four possible 2,5,6-trinitrocyclohex-3-enones (6), (7), (8) and (9), three 4,5,6-trinitrocyclohex-2-enones (10), (11) and [(12) or (13)], the 2-hydroxy-5,6-dinitrocyclohex-3-enone (14), quinone (17) and the 4-nitro dienone (3). The fuming nitric acid nitration of pentamethylphenol (1) for 90 h gives most of these products, except that 4-nitratomethyl-2,5,6-trinitrocyclohex-3-eones (21), (22), (23) and (24) are isolated. X-ray crystal structures are reported for compounds (6), (7), (8), (10), (11), (14) and (21).


1985 ◽  
Vol 38 (11) ◽  
pp. 1693 ◽  
Author(s):  
MP Hartshorn ◽  
JM Readman ◽  
WT Robinson ◽  
J Vaughan ◽  
AR Whyte

The nitration of 2,6-dimethyl-4-nitrophenol (1b), with either fuming nitric acid in acetic acid or nitrogen dioxide in dichloromethane, gives the C2-epimeric hydroxy trinitro ketones (4) and (5), the dinitro phenol (6) and the dihydroxy dinitro ketone (7). The nitration of the 4-bromo phenol (1c) is accompanied by some nitro- debromination and compounds (4), (5) and (13)-(17) are isolated. X-ray structure determinations are reported for compounds (5), (7) and (14).


1982 ◽  
Vol 35 (11) ◽  
pp. 2229 ◽  
Author(s):  
AM Chittenden ◽  
MP Hartshorn ◽  
KE Richards ◽  
WT Robinson ◽  
KH Sutton ◽  
...  

Nitration of 3,4,5-tribromo-2,6-dimethylphenol (10) with fuming nitric acid in acetic acid gives the C2-epimeric 2,5-dinitrocyclohex-3-enones (11) and (12), the structures of which were determined by single-crystal X-ray analyses. Some implications of these structural data are discussed.


1983 ◽  
Vol 36 (8) ◽  
pp. 1589 ◽  
Author(s):  
MP Hartshorn ◽  
RJ Martyn ◽  
WT Robinson ◽  
KH Sutton ◽  
J Vaughan ◽  
...  

Nitrations of phenols (3a), (3b), (7) and (8) with nitrogen dioxide in cyclohexane give similar patterns of reaction to those with fuming nitric acid in acetic acid. Nitration of 2,4-dibromo-3,5,6-trimethyl- phenol (19) with nitrogen dioxide gives isomeric trinitrocyclohex-3-enones (24), while fuming nitric acid reactions yield either the trinitro ketone (24a) and the cis-dinitro ketone (25) or the C2-epimeric ketones (25) and (26) depending upon the reaction conditions. Some reactions of these products are described, and the X-ray crystal structure of the epoxycyclopentene derivative (30) is reported.


2003 ◽  
Vol 2003 (9) ◽  
pp. 556-558 ◽  
Author(s):  
James R. Hanson ◽  
Peter B. Hitchcock ◽  
Jorge A.R. Salvador

The X-ray crystal structures of some 21-alkylpregnanes have been determined and the effects of a 16α,17α-epoxide and 21-methyl group on the conformation of the side chain are discussed.


1975 ◽  
Vol 48 (7) ◽  
pp. 2112-2115 ◽  
Author(s):  
Hitomi Suzuki ◽  
Katsuro Ishizaki ◽  
Shigeru Maruyama ◽  
Terukiyo Hanafusa

CORROSION ◽  
1957 ◽  
Vol 13 (12) ◽  
pp. 55-61 ◽  
Author(s):  
DAVID M. MASON ◽  
LOIS L. TAYLORS ◽  
JOHN B. RITTENHOUSE

Abstract Measurements were made at 130 degrees F of the extent of corrosion of several metals exposed to the liquid and the gas phase of thermally stable nitric acid containing 11 to 13 weight percent nitrogen dioxide and 2 to 4 weight percent water with and without hydrofluoric acid added as a corrosion inhibitor. Liquid-phase corrosion of the following metals was readily inhibited by hydrofluoric acid in fuming nitric acid of this composition: aluminum alloys 2S-0 (1100), 14S-T6 (2014-T6), 17S-T4 (2017-T4), 24S-T4 (2024-T4), 61S-T6 (6061-T6), and 75S-T6 (7075-T6); aluminum 2S-0 welded to 356; and chromium-nickel steels 302, 303, 304, 321, 347, Armco 17-7PH, and Uniloy 19-9DL and 19-9DX. Carbon steel C1020 and chromium alloy steels 4130, 410, 430, and 446 having intact natural metal oxide films, which were formed in moist air, were inhibited by hydrofluoric acid. Corrosive attack of these steels without the oxide film, however, was aggravated by the presence of hydrofluoric acid in fuming nitric acid, the corrosion becoming more extensive the lower the chromium content of the steel. Commercially pure lead was inhibited by hydrofluoric acid, whereas pure chromium, Nickel-A, tantalum, and titanium alloys 75A and 130A were either only slightly inhibited or showed corrosion rates which actually were increased by presence of hydrofluoric acid in fuming nitric acid. Inhibition of gas-phase corrosion was found to occur readily in the case of the following metals tested: steels 303, 410, 430, and 446 and aluminum 61S-T6. Gas-phase corrosion of steels 4130 and 1020 was usually aggravated by hydrofluoric acid. Exposure of aluminum 61S-T6 and stainless steel 347 to fuming nitric acid with a repeated cycling of temperature between 70 and 160 degrees F was found not to impair the inhibiting effect of hydrofluoric acid on gas and liquid-phase corrosion of these metals. A few tests of the liquid and gas-phase corrosion of aluminum 61S-T6 and steels C1020 and 347 by nitrogen dioxide at 130 degrees F were also made, and this medium was found in general to be much less corrosive than fuming nitric acid. 4.3.2


1982 ◽  
Vol 35 (6) ◽  
pp. 1237 ◽  
Author(s):  
MJ Gray ◽  
MP Hartshorn ◽  
KE Richards ◽  
WT Robinson ◽  
KH Sutton ◽  
...  

Nitration of 1,2,3,4-tetramethyl-5,6-dinitrobenzene (1) with fuming nitric acid in dichloromethane gives cis-and trans-2,5,6,6-tetramethyl-2,3,4,5-tetranitrocyclohex-3-enones (9) and (10), the structure of the cis isomer being confirmed by X-ray crystal structure analysis. The mechanism of formation of tetranitro ketones (9) and (10) is discussed.


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