THE ALPHA AND BETA 1,3,4,6-TETRAACETYL-D-GLUCOPYRANOSES AND THEIR CHLOROACETYL DERIVATIVES

1953 ◽  
Vol 31 (11) ◽  
pp. 1040-1047 ◽  
Author(s):  
R. U. Lemieux ◽  
G. Huber
Keyword(s):  
Acetic Acid ◽  
Silver Acetate

Reaction of 3,4,6-triacetyl-β-D-glucopyranosyl chloride with silver acetate in acetic acid gave 1,3,4,6-tetraacetyl-α-D-glucopyranose, m.p. 97–98 °C., [α]D + 145° (chloroform). 3,4,6,-Triacetyl-α-D-glucopyrartosyl chloride, m.p. 93–94 °C., [α]D + 185° (chloroform), prepared from the β-anomer by isomerization in acetone, with silver acetate in acetic acid gave 1,3,4,6-tetraacetyl-β-D-glucopyranose, m.p. 137–138 °C., [α]D + 26° (chloroform). The structures of these glucose tetraacetates were established by the interconversion of chloroacetyl derivatives.

Stereoselective deprotonation of tropinone and reactions of tropinone lithium enolate

1992 ◽  
Vol 70 (10) ◽  
pp. 2618-2626 ◽  
Author(s):  
Marek Majewski ◽  
Guo-Zhu Zheng
Keyword(s):  
Acetic Acid ◽  
Ring Opening ◽  
Aldol Reaction ◽  
Ethyl Chloroformate ◽  
Lithium Diisopropylamide ◽  
Silver Acetate ◽  
Lithium Amides ◽  
Lithium Enolate ◽  
The Absolute ◽  
Absolute Stereochemistry

Tropinone (6) was deprotonated with lithium diisopropylamide and with chiral lithium amides (18–24) and the resulting enolates (two enantiomers) were treated with electrophiles. The aldol reaction with benzaldehyde and deuteration were both diastereoselective. The former yielded only one isomer (exo, anti) of the aldol 8a; the latter proceeded from the exo face. This selectivity permitted us to probe the deprotonation of tropinone with lithium amides; it was concluded that the reaction involves predominantly the exo axial protons. The reaction of tropinone enolate with ethyl chloroformate led, via a ring opening, to the cycloheptenone derivative 9. The reaction with methyl cyanoformate yielded, in the presence of silver acetate and acetic acid, the β-ketoester 8b; however, in the absence of these additives, and especially when 12-crown-4 was added to the enolate, a ring opening leading to the pyrrolidine derivative 10 occurred instead. Deprotonation of tropinone with chiral lithium amides proceeded with modest enantioselectivity. A synthesis of non-racemic anhydroecgonine via this strategy allowed establishing the absolute stereochemistry of deprotonation.

Improved synthesis of anti-sesquinorbornene

1984 ◽  
Vol 62 (9) ◽  
pp. 1840-1844 ◽  
Author(s):  
Karl R. Kopecky ◽  
Alan J. Miller
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Carboxylic Acid ◽  
Lead Tetraacetate ◽  
Carboxyl Group ◽  
Silver Acetate ◽  
Benzenesulfonyl Chloride ◽  
Methoxide Ion ◽  
Hydrolysis Of ◽  
Monomethyl Ester

Treatment of methyl hydrogen decahydro-1,4:5,8-exo,endo-dimethanonaphthalene-4a,8a-dicarboxylate with lead tetraacetate in benzene – acetic acid replaces the carboxyl group by an acetoxy group. Hydrolysis of this product with 25% sulfuric acid at 130 °C forms 8a-hydroxydecahydro-1,4:5,8-exo,endo-dimethanonaphthalene-4a-carboxylic acid 10. The reaction between 10 and benzenesulfonyl chloride in pyridine containing triethylamine at 95 °C produces anti-sesquinorbornene 1 in 34% yield. In the absence of triethylamine 1 is converted to the hydrochloride. The iodohydroperoxide of 1 is converted by silver acetate at 0 °C to the diketone in a luminescent reaction. The 1,2-dioxetane could not be isolated. Decahydro-1,4:5,8-exo,exo-dimethanonaphthalene-4a,8a-dicarboxylic anhydride is converted slowly by methoxide ion in methanol at 150 °C to the monomethyl ester which then undergoes demethylation. The isomeric exo,endo anhydride undergoes reaction readily with methoxide ion at 80 °C.

Conductivity of the Liquid System Water + Acetic Acid + Silver Acetate

1978 ◽  
Vol 33 (9) ◽  
pp. 1105-1106
Author(s):  
R. Haase ◽  
H. Ben Nasr ◽  
K .-H . Dücker
Keyword(s):  
Acetic Acid ◽  
Ternary System ◽  
Electric Conductivity ◽  
Infinite Dilution ◽  
Liquid System ◽  
Silver Acetate ◽  
Equivalent Conductivity ◽  
Experimental Values ◽  
Limiting Values ◽  
System Water

We present and discuss experimental values of the electric conductivity (and of the density) for the liquid ternary system water + acetic acid + silver acetate at 25 °C. The results given here represent a selection from measurements on more than 200 compositions. The concepts of equivalent conductivity and of limiting values for infinite dilution in the ternary system are also dealt with briefly.

The reaction of cis- and trans-1,2-dianisyl-2-phenylvinyl-2-13C bromides with acetic acid and silver acetate

1976 ◽  
Vol 54 (4) ◽  
pp. 604-609 ◽  
Author(s):  
Choi Chuck Lee ◽  
Mitsuo Oka
Keyword(s):  
Acetic Acid ◽  
Analogous Reaction ◽  
Silver Acetate ◽  
Cis And Trans

The reaction of cis- or trans-1,2-dianisyl-2-phenylvinyl-2-13C bromide with HOAc–AgOAc gave a 1:1 mixture of cis- and trans-1,2-dianisyl-2-phenylvinyl-2-13C acetates with no isotopic scrambling according to pmr and cmr analyses. The lack of degenerate 1,2-phenyl shift in this system is in contrast with the finding of about 7% scrambling in the analogous reaction with triphenylvinyl-2-13C bromide and mechanistic implications of this difference are discussed.

Furoquinolines Part VI: Synthesis of Furo(2,3-b)quinolines

1973 ◽  
Vol 28 (3-4) ◽  
pp. 196-199 ◽  
Author(s):  
P. Shanmugam ◽  
R. Palaniappan
Keyword(s):  
Acetic Acid ◽  
Phosphoric Acid ◽  
Silver Acetate

3-Vinyl-2-quinolone, its 6,7-dimethoxy, 7,8-dimethoxy and 6,7-methylenedioxy derivatives are converted into the corresponding 3-acetoxy-2,3-dihydrofuro(2,3-b)quinolines by way of iodoacetoxylation using iodine and excess silver acetate in acetic acid. Dehydroacetoxylation of the acetoxy compounds, accomplished by heating with 88-93% o-phosphoric acid, furnished the corresponding furo(2,3-b)quinolines.

THE BROMINOLYSIS OF CARBOHYDRATE IODIDES: I. ACETYLATED 6-DEOXY-6-IODO AND 2-DEOXY-2-IODO GLYCOSIDES

1964 ◽  
Vol 42 (3) ◽  
pp. 539-546 ◽  
Author(s):  
R. U. Lemieux ◽  
B. Fraser-Reid
Keyword(s):  
Acetic Acid ◽  
Methoxy Group ◽  
Glacial Acetic Acid ◽  
Main Product ◽  
Zinc Dust ◽  
Potassium Acetate ◽  
Borohydride Reduction ◽  
Silver Acetate ◽  
Sodium Borohydride Reduction ◽  
Dust Reduction

Reaction of methyl 6-deoxy-6-iodo-α-D-glucopyranoside triacetate with an excess of bromine in glacial acetic acid; N in potassium acetate, gave a 1.1:1 mixture of the products resulting from replacement of the iodine by bromine and by acetoxy group, respectively. When 2 moles of silver acetate were present per mole of bromine, the reaction was much more rapid and only methyl α-D-glucopyranoside tetraacetate was formed. The brominolysis of methyl 2-deoxy-2-iodo-α-D-mannopyranoside triacetate proceeded at a useful rate only when catalyzed by silver acetate. The main product of the reaction appeared to be methyl 3-acetoxy-2-bromo-2-deoxy-α-D-arabino-hexopyranoside triacetate. The compound could be converted by way of sodium borohydride reduction to methyl 2-bromo-2-deoxy-α-D-altropyranoside and by way of zinc dust reduction to methyl 2-deoxy-α-D-erythro-hexopyranoside-3-ulose diacetate. About 20% of the reaction proceeded with migration of the methoxy group to the 2-position to yield 2-O-methyl-D-glucose tetraacetate. The mechanisms of these reactions are discussed.

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