Reactions of 5α-hydroxy-steroids: the mechanism of backbone rearrangement in sulphuric acid–acetic acid–acetic anhydride

The acetolyses of the alpha and beta methyl D-glucopyranoside tetraacetates in 1:1 acetic acid – acetic anhydride 0.5 M with respect to sulphuric acid were followed at 25 °C. by isotopic dilution analysis of products isolated after various intervals of time. The reaction of the α-glucoside was found to proceed mainly with inversion of the anomeric center. On the other hand, the β-glucoside was found to undergo acetolysis with retention of configuration concurrent with anomerization. It was shown that the polarimetric changes observed in the course of the reactions could be satisfactorily accounted for on the basis of these reaction routes. Reaction mechanisms are suggested.

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Electrophilic aromatic substitution. Part XII. The nitration of 1-acetamidonaphthalene in acetic anhydride, in acetic acid, and in sulphuric acid

Journal of the Chemical Society Perkin Transactions 2 ◽

10.1039/p29720001652 ◽

1972 ◽

pp. 1652 ◽

Cited By ~ 3

Author(s):

S. R. Hartshorn ◽

K. Schofield

Keyword(s):

Acetic Acid ◽

Acetic Anhydride ◽

Sulphuric Acid ◽

Electrophilic Aromatic Substitution ◽

Aromatic Substitution

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

Australian Journal of Chemistry ◽

10.1071/ch9741505 ◽

1974 ◽

Vol 27 (7) ◽

pp. 1505 ◽

Cited By ~ 5

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.

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Photochemical reactions of azo compounds. VII. Studies of the photochemical reactions of azobenzene under various acidic conditions

Australian Journal of Chemistry ◽

10.1071/ch9661445 ◽

1966 ◽

Vol 19 (8) ◽

pp. 1445 ◽

Cited By ~ 6

Author(s):

GE Lewis ◽

RJ Mayfield

Keyword(s):

Acetic Acid ◽

Acetic Anhydride ◽

Sulphuric Acid ◽

Photochemical Reaction ◽

Acetyl Chloride ◽

Photochemical Reactions ◽

Aluminium Chloride ◽

Azo Compounds ◽

High Yield ◽

Acidic Conditions

An investigation has been made of the photochemical and dark reactions of azobenzene in acetic acid-ferric chloride and acetic acid-aluminium chloride mixtures for comparison with the corresponding reactions of azobenzene in sulphuric acid. The photochemical reactions resulted in cyclodehydrogenation of azobenzene to benzo[c]cinnoline, and small quantities of reduction products of azobenzene were also isolated. The formation of reduction products was again observed in the dark reactions, but there was no sign of cyclodehydrogenation. The significance of these observations is now discussed. Irradiation of azobenzene in acetyl chloride, or in acetic anhydride containing hydrogen chloride, resulted in a novel photochemical reaction in which NN?-diacetyl-4-chlorohydrazobenzene was formed in high yield.

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Vapor-liquid equilibria in mixtures containing an associating substance. III. Binary and ternary systems of water, acetic acid and acetic anhydride at 400 mm Hg

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19560269 ◽

1956 ◽

Vol 21 (2) ◽

pp. 269-280 ◽

Cited By ~ 8

Author(s):

J. Marek

Keyword(s):

Acetic Acid ◽

Acetic Anhydride ◽

Ternary Systems ◽

Vapor Liquid Equilibria ◽

Binary And Ternary Systems ◽

Vapor Liquid

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An unusual reaction of a bridged triterpenoid α-diketone with acetic anhydride

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19912917 ◽

1991 ◽

Vol 56 (12) ◽

pp. 2917-2935 ◽

Cited By ~ 1

Author(s):

Eva Klinotová ◽

Václav Křeček ◽

Jiří Klinot ◽

Miloš Buděšínský ◽

Jaroslav Podlaha ◽

...

Keyword(s):

Acetic Acid ◽

Nmr Spectroscopy ◽

Acetic Anhydride ◽

Spectral Methods ◽

X Ray Diffraction ◽

X Ray ◽

Mild Conditions ◽

Condensation Products ◽

Unsaturated Lactones ◽

C Nmr

3β-Acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) reacts with acetic anhydride in pyridine under very mild conditions affording β-lactone IVa and γ-lactones Va and VIIa as condensation products. On reaction with pyridine, lactones Va and VIIa undergo elimination of acetic acid to give unsaturated lactones VIIIa and IXa, respectively. Similarly, the condensation of 20β,28-epoxy-21,22-dioxo-18α,19βH-ursan-3β-yl acetate (IIIb) with acetic anhydride leads to β-lactone IVb and γ-lactone Vb; the latter on heating with pyridine affords unsaturated lactone VIIIb and 21-methylene-22-ketone Xb. The structure of the obtained compounds was derived using spectral methods, particularly 1H and 13C NMR spectroscopy; structure of lactone IVa was confirmed by X-ray diffraction.

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