2-Substituted and 2,6-disubstituted 1,4-benzoquinone 4-oxime acetates

1971 ◽  
Vol 24 (7) ◽  
pp. 1449 ◽  
Author(s):  
RK Norris ◽  
S Sternhell
Keyword(s):  
Acetic Anhydride ◽  
Physical Properties ◽  
Sulphuric Acid ◽  
Probable Mechanism ◽  
Effect Of Substituents ◽  
Infrared Data

The preparation and physical properties of 19 compounds in the title series are described. The acetates were prepared by treatment of the corresponding benzoquinone oximes or p-nitrosophenols with acetic anhydride in the presence of catalytic amounts of pyridine. The syn and anti isomers can be equilibrated in acetic anhydride solutions containing traces of sulphuric acid. The effect of substituents at C2 on the position of the syn-anti equilibria is very similar to their effect in the corresponding 1,4-benzoquinone 4-oximes. N.m.r. parameters, electronic and infrared data, photochemical syn-anti conversions, and the probable mechanism of the acid-catalysed equilibration are discussed.

Reactions of 5-Hydroxy steroids. XIII. The acid-catalysed reactions of Cholestane-4,5-diol 4-acetates and Cholestane-4,5-diol diacetates

1974 ◽  
Vol 27 (7) ◽  
pp. 1505 ◽  
Author(s):  
ETJ Bathurst ◽  
JM Coxon ◽  
MP Hartshorn
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Sulphuric Acid ◽  
Thionyl Chloride ◽  
Effect Of Substituents ◽  
Carbonium Ion ◽  
Rearrangement Process ◽  
Acid Catalysed Reactions

The reaction of 5α-cholestane-4α,5-diol 4-acetate (lb) with sulphuric acid-acetic anhydride-acetic acid occurs almost exclusively by loss of the 6α-proton to give cholest-5-en-4a-yl acetate (3) while dehydration with thionyl chloride-pyridine occurs predominantly (c. 80%) by loss of the 6β-proton. On reaction with D2SO4-DOAc-Ac2O, 5α-cholestane-4β,5-diol 4-acetate (7) undergoes backbone rearrangement to give olefins (9),(10) and (11) without incorporation of deuterium and thus excludes the intermediacy of olefins and cyclopropanes in the rearrangement process. The effect of substituents on these reactions has been rationalized by consideration of the initial conformation of the C5 carbonium ion.

REACTIONS OF PHENYL-SUBSTITUTED HETEROCYCLIC COMPOUNDS: V. NITRATIONS OF 1,3- AND 1,5-DIPHENYLPYRAZOLES

1964 ◽  
Vol 42 (7) ◽  
pp. 1605-1615 ◽  
Author(s):  
Brian M. Lynch ◽  
Yuic-Yung Hung
Keyword(s):  
Nitric Acid ◽  
Magnetic Resonance ◽  
Acetic Anhydride ◽  
Sulphuric Acid ◽  
Heterocyclic Compounds ◽  
Substituted 1

Dinitration of 1,3- or 1,5-diphenylpyrazole in sulphuric acid yields the corresponding di(p-nitrophenyl) compounds, while nitric acid–acetic anhydride yields the 4-nitro-1-p-nitrophenyl compounds.Mononitration at the 4-position occurs when the diphenylpyrazoles and several other 1-phenylpyrazoles are nitrated at 0° by nitric acid–acetic anhydride.Possible explanations of the dependence of orientation on the nature of the nitrating agent-are discussed.Nuclear magnetic resonance (n.m.r.) spectroscopy was used in demonstrating the structures of many of the nitration products, and a general discussion of the n.m.r. spectra of substituted 1-phenylpyrazoles is given.

Cyclic nitrones. II. Reactions of a cyclic α-keto nitrone with acetic anhydride, acetone, and methyl acetoacetate

1967 ◽  
Vol 20 (11) ◽  
pp. 2485 ◽  
Author(s):  
RFC Brown ◽  
WD Crow ◽  
L Subrahmanyan ◽  
CS Barnes
Keyword(s):  
Acetic Anhydride ◽  
Sulphuric Acid ◽  
Functional Groups ◽  
Potassium Hydroxide ◽  
Methyl Acetoacetate ◽  
Cyclic Nitrones ◽  
Aqueous Potassium Hydroxide ◽  
Isopropenyl Acetate

The cyclic α-keto nitrone 3,4,5,6-tetrahydro-5,5-dimethyl-3-oxopyridine 1-oxide (III) when treated with acetic anhydride and sulphuric acid gave in low yield a compound (XI) having both enol lactone and vinylogous amide functional groups. Hydrolysis and decarboxylation of compound (XI) with aqueous potassium hydroxide gave a vinylogous amide (V), also obtained by acid- or base-catalysed condensation of compound (III) with isopropenyl acetate or acetone. Base-catalysed condensation of (III) with methyl acetoacetate gave an ester (XVII) closely related to compound (V).

scholarly journals On the Solar Dust Ring(s)

1985 ◽  
Vol 85 ◽  
pp. 59-62
Author(s):  
T. Mukai
Keyword(s):  
Physical Properties ◽  
Preliminary Analysis ◽  
Dust Grains ◽  
Ring Particle ◽  
Dust Ring ◽  
Infrared Data

AbstractBased on a mechanism to form the solar dust ring, it is proved that the observed peak in infrared F-corona cannot be explained by silicate type grain alone. Preliminary analysis on the recent infrared data of F-corona by Maihara et al.(1984) has suggested that the ring particle has different physical properties compared with the dust grains, which produce the background F-corona.

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