Reactions of 2,6-Di-t-butyl-4-methylphenol with nitrogen dioxide; X-ray crystal structures of 2,6-Di-t-butyl-c-6-hydroxy-4-methyl-r-4,c-5-dinitrocyclohex-2-enone and 2,6-Di-t-butyl-4-methyl-r-4,c-5,c-6-trinitrocyclohex-2-enone

1983 ◽  
Vol 36 (11) ◽  
pp. 2339 ◽  
Author(s):  
MP Hartshorn ◽  
KH Sutton ◽  
J Vaughan
Keyword(s):  
Nitrogen Dioxide ◽  
Crystal Structures ◽  
X Ray

Reaction of 2,6-di-t-butyl-4-methylphenol (6) with nitrogen dioxide in benzene gives the trinitro ketone (11), but in cyclohexane gives both trinitro ketone (11) and the hydroxy dinitro ketone (12),in addition to the 4-nitro dienone (10). Some reactions and X-ray crystal structures of compounds (11) and (12) are described.

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
Keyword(s):  
Nitric Acid ◽  
Nitrogen Dioxide ◽  
Crystal Structures ◽  
Side Chain ◽  
X Ray ◽  
Fuming Nitric Acid

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.

The nitration of pentamethylphenol

1984 ◽  
Vol 37 (7) ◽  
pp. 1489 ◽  
Author(s):  
MP Hartshorn ◽  
WT Robinson ◽  
J Vaughan ◽  
JM White ◽  
AR Whyte
Keyword(s):  
Nitric Acid ◽  
Nitrogen Dioxide ◽  
Crystal Structures ◽  
X Ray ◽  
Fuming Nitric Acid

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).

Reactions of 3,4,5-Trimethylbiphenyl and 2,3,4-Trimethylbiphenyl With Nitrogen Dioxide

1990 ◽  
Vol 43 (9) ◽  
pp. 1519 ◽  
Author(s):  
MP Hartshorn ◽  
MC Judd ◽  
RJ Martyn ◽  
WT Robinson ◽  
GJ Wright ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Crystal Structures ◽  
Nitroaromatic Compounds ◽  
Similar Reaction ◽  
X Ray ◽  
Nitrate Esters ◽  
Elimination Mechanism

Reaction of 3,4,5-trimethylbiphenyl (1) with nitrogen dioxide gives four mononitro compounds (3)-(6) and three dinitro compounds (7)-(9). Similar reaction of 2,3,4-trimethylbiphenyl (2) gives three nitroaromatic compounds (11)-(13), three nitrate esters (14)-(16), and two nitro dienones (17) and (18). Dinitro dienone (17) rearranges in solution to give the corresponding hydroxy nitro dienone (19). The differences between the two sets of products are discussed, and an addition-elimination mechanism is proposed for the mode of formation of the nitro dienones (17) and (18). X-Ray crystal structures are reported for compounds (4) and (19).

The Chlorination of 2-t-Butyl-4-chloro-6-methylphenol. Some Reactions of Chlorine and Nitrogen Dioxide With 6-Chlorocyclohexa-2,4-dienones Derived From 2-t-Butyl-4-chloro-6-methylphenol

1992 ◽  
Vol 45 (4) ◽  
pp. 721 ◽  
Author(s):  
MP Hartshorn ◽  
AD Roddick ◽  
PJ Steel ◽  
GJ Wright
Keyword(s):  
Nitrogen Dioxide ◽  
Crystal Structures ◽  
X Ray

Chlorinations of 2-t-butyl-4-chloro-6-methylphenol(10) and of the mixture of 4,6-dichlorocyclo-hexa-2,ddienones (11) and (12) give the tetrachloro ketones (13)-(15). Reaction of the dichlorocyclohexa-2,4-dienone mixture with nitrogen dioxide gives predominantly dichloro dinitro ketones (17) which rearrange on chromatography to yield the hydroxy dienone (21). X-Ray crystal structures are reported for compounds (13)-(15), (20) and (21).

reactions of 2-t-Butyl-4,6-dimethylphenol, 2,4-Di-t-butyl-6-methylphenol and 2,4,6-Tri-t-butylphenol with Nitrogen Dioxide

1985 ◽  
Vol 38 (1) ◽  
pp. 161 ◽  
Author(s):  
MP Hartshorn ◽  
WT Robinson ◽  
KH Sutton ◽  
J Vaughan
Keyword(s):  
Nitrogen Dioxide ◽  
Crystal Structures ◽  
Similar Reaction ◽  
X Ray

Reaction of 2-t-butyl-4,6-dimethylphenol(10) with nitrogen dioxide in benzene gives the C4-epimeric 4,5,6-trinitrocyclohex-2-enones (13) and (14). In contrast, similar reaction of 2,4-di-t-butyl-6-methyl-phenol (11) gives substituted cyclohex-3-enones, 2,5,6-trinitro ketones (20)- (23), 2-hydroxy-5,6-dinitro ketones (27) and (28) and the 6-hydroxy- 2,5-dinitro ketone (29). Reaction of 2,4,6-tri-t-butylphenol (12) with nitrogen dioxide gives initially the 4-nitro dienone (35), but de-t- butylated products (36) and (37) are formed in long-term reactions. X- ray crystal structures are reported for compounds (13),(14),(21),(22), (23), (27), (28) and (29).

The Reaction of 2,3,5,6-Tetramethyl-4-nitrophenol with Nitrogen Dioxide

1985 ◽  
Vol 38 (1) ◽  
pp. 145 ◽  
Author(s):  
MP Hartshorn ◽  
WT Robinson ◽  
JWJM Vaughan
Keyword(s):  
Nitrogen Dioxide ◽  
Crystal Structures ◽  
X Ray

Reaction of 2,3,5,6-tetramethyl-4-nitrophenol (21) with nitrogen dioxide in benzene gives the four isomeric 2,4,5,6-tetranitrocyclohex- 3-enones (24)-(27), 2-hydroxy-4,5,6-trinitrocyclohex-3-enone (31), the C2-epimeric 6-hydroxy-2,4,5-trinitrocyclohex-3-enones (32) and (36) and the 2,6-dihydroxy-4,5-dinitrocyclohex-3-enone (33). X-ray crystal structures are reported for compounds (24), (25), (31), (32), (36) and the cyclopentenediol (37).

The nitration of 4-Nitro- and 4-Bromo-2,6-dimethylphenols; X-Ray Crystal Structures of t-6-Hydroxy-2,6-dimethyl-r-2,4,t-5-trinitrocyclohex-3-enone, r-2,t-6-Dihydroxy-2,6-dimethyl-4,t-5-dinitrocyclohex-3-enone and 4-Bromo-t-6-hydroxy-2,6-dimethyl-r-2,t-5-dinitrocyclohex-3-enone

1985 ◽  
Vol 38 (11) ◽  
pp. 1693 ◽  
Author(s):  
MP Hartshorn ◽  
JM Readman ◽  
WT Robinson ◽  
J Vaughan ◽  
AR Whyte
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Nitrogen Dioxide ◽  
Crystal Structures ◽  
X Ray ◽  
Structure Determinations ◽  
Fuming Nitric Acid

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).

Transmission electron microscope studies in special ceramics

1978 ◽  
Vol 36 (1) ◽  
pp. 268-269
Author(s):  
A. Zangvil ◽  
L.J. Gauckler ◽  
G. Schneider ◽  
M. Rühle
Keyword(s):  
Phase Diagrams ◽  
Crystal Structures ◽  
Thin Foil ◽  
Limited Extent ◽  
Complex Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Lattice Resolution

The use of high temperature special ceramics which are usually complex materials based on oxides, nitrides, carbides and borides of silicon and aluminum, is critically dependent on their thermomechanical and other physical properties. The investigations of the phase diagrams, crystal structures and microstructural features are essential for better understanding of the macro-properties. Phase diagrams and crystal structures have been studied mainly by X-ray diffraction (XRD). Transmission electron microscopy (TEM) has contributed to this field to a very limited extent; it has been used more extensively in the study of microstructure, phase transformations and lattice defects. Often only TEM can give solutions to numerous problems in the above fields, since the various phases exist in extremely fine grains and subgrain structures; single crystals of appreciable size are often not available. Examples with some of our experimental results from two multicomponent systems are presented here. The standard ion thinning technique was used for the preparation of thin foil samples, which were then investigated with JEOL 200A and Siemens ELMISKOP 102 (for the lattice resolution work) electron microscopes.

Crystal Structures of Fragments D and Double-D from Fibrinogen and Fibrin

1999 ◽  
Vol 82 (08) ◽  
pp. 271-276 ◽  
Author(s):  
Glen Spraggon ◽  
Stephen Everse ◽  
Russell Doolittle
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Crystal Structures ◽  
Structure And Function ◽  
X Ray ◽  
Long Period ◽  
And Function

IntroductionAfter a long period of anticipation,1 the last two years have witnessed the first high-resolution x-ray structures of fragments from fibrinogen and fibrin.2-7 The results confirmed many aspects of fibrinogen structure and function that had previously been inferred from electron microscopy and biochemistry and revealed some unexpected features. Several matters have remained stubbornly unsettled, however, and much more work remains to be done. Here, we review several of the most significant findings that have accompanied the new x-ray structures and discuss some of the problems of the fibrinogen-fibrin conversion that remain unresolved. * Abbreviations: GPR—Gly-Pro-Arg-derivatives; GPRPam—Gly-Pro-Arg-Pro-amide; GHRPam—Gly-His-Arg-Pro-amide

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