Carbanions in Carbohydrate Chemistry: Synthesis of C-Glycosyl Malonates

1974 ◽  
Vol 52 (8) ◽  
pp. 1266-1279 ◽  
Author(s):  
Stephen Hanessian ◽  
Andre G. Pernet
Keyword(s):  
Acetic Acid ◽  
Malonic Acid ◽  
Diethyl Malonate ◽  
Major Product ◽  
Carbohydrate Chemistry ◽  
Anomeric Configuration ◽  
Bromide Ion ◽  
Chemical Correlation ◽  
Shift Reagents

The condensation of 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide with sodio diethyl malonate led to crystalline diethyl 2-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl) malonate. The corresponding dibenzyl ester proved to be a versatile intermediate for the preparation of crystalline β-D-glucopyranosyl malonic acid and β-D-glucopyranosyl acetic acid derivatives. The anomeric configuration in these C-glycosides was determined by a chemical correlation. With 2,3,4,6-tetra-O-acetyl- β-D-glucopyranosyl chloride and sodio diethyl malonate, the major product was a 1,2-O-ketal derivative resulting from an attack of the carbanion on the 1,2-acetoxonium ion. The condensation of 2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl bromide with sodio diethyl malonate was conducted with, and without added bromide ion and the mechanistic implications of the results are discussed. C-Glycosides were also prepared in the D-mannofuranose series and their transformation into the D-lyxofuranose series (anomeric mixture) is described. The utility of n.m.r. shift reagents, and an apparent differential complexation by Eu(DPM)3 and Eu(FOD)3-d27 is demonstrated.

scholarly journals On the hydrolysis of diethyl 2-(perfluorophenyl)malonate

2020 ◽  
Vol 16 ◽  
pp. 1863-1868
Author(s):  
Ilya V Taydakov ◽  
Mikhail A Kiskin
Keyword(s):  
Acetic Acid ◽  
Malonic Acid ◽  
Diethyl Malonate ◽  
Toxic Substances ◽  
New Approach ◽  
Preparative Yield ◽  
Benzyl Halides ◽  
Acidic Conditions ◽  
Hydrolysis Of ◽  
Sodium Diethyl Malonate

Diethyl 2-(perfluorophenyl)malonate was synthesized in 47% isolated yield by the reaction of sodium diethyl malonate and hexafluorobenzene. The resulting compound was considered as a starting material for synthesizing 2-(perfluorophenyl)malonic acid by hydrolysis. It was found that the desired 2-(perfluorophenyl)malonic acid could not be obtained from this ester by hydrolysis, neither under basic nor under acidic conditions. Nevertheless, hydrolysis of the ester with a mixture of HBr and AcOH gave 2-(perfluorophenyl)acetic acid in a good preparative yield of 63%. A significant advantage of this new approach to 2-(perfluorophenyl)acetic acid is that handling toxic substances such as cyanides and perfluorinated benzyl halides is avoided.

Coordination state of cobalt(II) ions in solution and on a sulphonated organic polymer

1979 ◽  
Vol 44 (8) ◽  
pp. 2330-2337 ◽  
Author(s):  
Jindřiška Maternová ◽  
Anastas A. Andreev ◽  
Dimitrii M. Shopov ◽  
Karel Setínek
Keyword(s):  
Acetic Acid ◽  
Coordination Sphere ◽  
Glacial Acetic Acid ◽  
Organic Polymer ◽  
Octahedral Complex ◽  
Coordination State ◽  
Tetrahedral Symmetry ◽  
Liquid Acid ◽  
Homogeneous Phase ◽  
Bromide Ion

It was found spectroscopically that cobalt(II) acetate dissolved in glacial acetic acid forms the octahedral complex [Co(OAc)2(HOAc)4] which in the presence of bromide ions gives the octahedral [Co(OAc)Br(HOAc)4] and tetrahedral bromo(acetate)cobalt(II) complexes with the higher number of Br- ions. When attached to an organic polymer cobalt(II) ions are bonded in the form of octahedral [Co(H2O)6]2+ cations which form with acetic acid similar complexes as in homogeneous phase and are able to coordinate one bromide ion. Drying the copolymer possessing octahedral hexaaquocobalt(II) cations leads to tetrahedral aquocomplexes which are solvated by gaseous acetic acid and converted into the acetate complexes with the liquid acid. The latter contain the acid in the inner coordination sphere and have tetrahedral symmetry.

Bromination of 5a-lanost-8-en-3-one and 5a-lanost-8-ene-3,7,ll-trione

1982 ◽  
Vol 35 (4) ◽  
pp. 857
Author(s):  
J Collins ◽  
PS Cooper ◽  
RE Gall ◽  
A Georges
Keyword(s):  
Acetic Acid ◽  
Sodium Borohydride ◽  
Major Product ◽  
Equilibrium Conditions

Monobromination of 5α-lanost-8-en-3-one (la) under kinetic conditions gave exclusively the 2β- bromo ketone (3a) whilst under equilibrium conditions the product contained 85% of the 2α-bromo ketone (2a). Monobromination of 5a-lanost-8-ene-3,7,11-trione (1b) under kinetic conditions gave the 2a-bromo ketone (2b); 33% of the 2β-bromo ketone (3b) was formed under equilibrium conditions. The configuration assigned to the bromo ketones (2b) and (3b) has been confirmed by reduction with sodium borohydride and treatment of the derived bromohydrins (4b) and (6b) with base to give the 2β,3β-epoxide (5b) and the 3-ketone (1b) respectively. Cleavage of the 2β,3β(-epoxide (5a) with acetic acid gave 2α-acetoxy-5α-lanost-8-en-3β-ol (7) as the major product and 3α-acetoxy-5α-lanost- 8-en-2β-ol (a), in a boat like conformation, as the minor product.

The synthesis of Tetracyclo[5,3,1,03,5,04,9]undecan-2-one and the acid-catalysed and reductive cleavages of the cyclopropyl ring

1975 ◽  
Vol 28 (10) ◽  
pp. 2255 ◽  
Author(s):  
DPG Hamon ◽  
GF Taylor
Keyword(s):  
Acetic Acid ◽  
Double Bond ◽  
Liquid Ammonia ◽  
Aqueous Acetic Acid ◽  
Bromide Ion ◽  
Independent Synthesis

Tetracyclo[5,3,1,03,5,04,9]undecan-2-one (2,4-dehydro-5-homoadamantanone) (3) was synthesized by copper-catalysed intramolecular insertion of a diazoketone into a double bond. Acid-catalysed opening of the cyclopropyl ring in aqueous acetic acid cleaved the C3-C4 bond to give a mixture of exo-7-hydroxytricyclo[4,3,1,13,8]undecan-4-one (13) and its acetate (12). Under the same conditions except for the presence of bromide ion, a mixture of (12), (13) and exo-7- bromotricyclo[4,3,1,13,8]-undecan-4-one (17) was obtained. Reduction of (17) with LiAlH4 gave homoadamantanol. Reduction of (3) with lithium in liquid ammonia gave cleavage of the C 3-C 5 bond to afford tricyclo[5,3,1,04,9]-undecan-2-one (4), the structure of which was confirmed by independent synthesis.

scholarly journals Conformational analysis in carbohydrate chemistry. V. Formation of glycosidic anhydrides from heptoses

1981 ◽  
Vol 59 (2) ◽  
pp. 379-383 ◽  
Author(s):  
Stephen John Angyal ◽  
Trung Quang Tran
Keyword(s):  
Conformational Analysis ◽  
Major Product ◽  
Carbohydrate Chemistry ◽  
Dioxane Ring

The position of the equilibrium between aldoheptoses and their glycosidic anhydrides depends crucially on the configuration of the heptose. Depending on that configuration, the 1,6-anhydropyranose, the 1,7-anhydropyranose, or the 1,6-anhydrofuranose is the major product, its proportion varying from 99% to less than 1%. The position of the equilibrium is predictable from conformational considerations. 1,7-Anhydrofuranoses have not been encountered. The 1,3-dioxane ring of the 1,7-anhydropyranoses was found to assume a skew form.

scholarly journals Synthesis and evaluation of possible mechanism of anti nociceptive potential of novel 2-quinolone fused 3,5-pyrazolidinedione derivatives in experimental animal models

2013 ◽  
Vol 24 (1) ◽  
pp. 5-12
Author(s):  
Abhishek Tiwari ◽  
Anita Singh
Keyword(s):  
Acetic Acid ◽  
Analgesic Activity ◽  
Diclofenac Sodium ◽  
Diethyl Malonate ◽  
Plate Model ◽  
Model Compounds ◽  
Hot Plate ◽  
Standard Drug ◽  
Experimental Animal Models ◽  
Drug Compound

AbstractIn the present synthesis a series of 1-(1-methyl-2-oxo-1,2-dihydroquinolin-4-yl)-2-substituted phenylpyrazolidine-3,5-diones were prepared. By the reaction of N-methylbenzenamine with diethyl malonoate 4-hydroxy-1-methylquinolin-2(1H)-one were prepared, which on treatment with posphoryl chloride converted into 4-chloro-1-methylquinolin-2(1H)-one. Subsequently with substituted phenyl hydrazines 1-methyl-4-(2- substitutedphenylhydrazinyl)quinolin-2(1H)-one were obtained, which on reaction with diethyl malonate gave 1- (1-methyl-2-oxo-1,2-dihydroquinolin-4-yl)-2-substituted phenylpyrazolidine-3,5-diones. All structures were characterized by IR, 1HNMR & mass spectrometry. Further all the synthesized compounds were evaluated for their anti-nociceptive activity in mice by Eddy’s hot plate and acetic acid induced writhing response. All compounds have shown the activity. In hot plate model compounds QAA-04c and QAA-04d have given more activity than standard, whereas in case of acetic acid induced writhing model compounds QAA-04a and QAA- 04d have given significant analgesic activity which is comparable with the standard drug. Compound QAA-04b has shown least analgesic activity. Compound QAA-04a was almost equal in activity to the standard drug diclofenac sodium and was considered as the lead molecule.

Biosynthesis of Lycopodine. The Question of the Intermediacy of Piperidine-2-acetic Acid

1975 ◽  
Vol 53 (1) ◽  
pp. 41-50 ◽  
Author(s):  
W. D. Marshall ◽  
T. T. Nguyen ◽  
D. B. MacLean ◽  
Ian D. Spenser
Keyword(s):  
Acetic Acid ◽  
Malonic Acid ◽  
Pipecolic Acid

In Lycopodiumtristachyum lycopodine is derived from L-lysine whereas pipecolic acid is derived from D-lysine. Malonic acid serves as a specific precurser of the non-lysine derived segments of lycopodine. Piperidine-2-acetic acid is not incorporated into the alkaloid.

Chemoselectivity in the Synthesis of 1,2,3-Triazoles from Enolizable Ketones, Primary Alkylamines, and 4-Nitrophenyl Azide

Synthesis ◽  
2017 ◽  
Vol 49 (18) ◽  
pp. 4191-4198 ◽  
Author(s):  
Joice Thomas ◽  
Wim Dehaen ◽  
Tomas Opsomer
Keyword(s):  
Acetic Acid ◽  
High Temperatures ◽  
Major Product ◽  
Metal Free ◽  
High Yields

In recent years, several organocatalytic/metal-free synthetic pathways towards 1,2,3-triazoles have been reported. One of them is a general metal-free route towards the synthesis of 1,5-di- or fully-substituted 1,2,3-triazoles, designed by our group and named the ‘triazolization’ reaction of ketones. Limitations of this route were encountered in reactions with more activated ketones, where the corresponding 1-(4-nitrophenyl)-1,2,3-triazole was found back as the major product. Interestingly, three different triazoles are formed when 1,3-diphenylacetone is used as the ketone. In the present work, 1,3-diphenylacetone was used as a model substrate to investigate the chemoselectivity of our metal-free route under different reaction circumstances. This led to the conclusion that the formation of the desired 1,2,3-triazole is favored in apolar solvents, at high temperatures, and in the presence of acetic acid. By using one equivalent of acetic acid, previously inaccessible fully decorated 1,2,3-triazoles can be synthesized from simple α-arylketones in moderate to high yields.

SYNTHESIS OF 2-, AND 3-NITROBENZANTHRONE VIA DIRECT NITRATION OF BENZANTHRONE WITH NITRIC ACID/ACETIC ACID

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Kefa K. Onchoke ◽  
Jorge J. Ojeda
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Acetic Anhydride ◽  
Standard Sample ◽  
Major Product ◽  
Fragmentation Patterns

Abstract Three mono-nitrobenzanthrone isomers (1-, 2-, and 3-nitrobenzanthrone; 1-, 2-, and 3-NBA) were synthesized by reacting benzanthrone (BA) with nitric acid (HNO3) in acetic anhydride at ice-cold conditions. The major product, 2-nitrobenzanthrone (2-NBA), was confirmed using GC-MS via comparisons with a standard sample. On the basis of the elution profiles and fragmentation patterns two other isomers formed were assigned to 1-, and 3-nitrobenzanthrone (1-, and 3-NBA). The average percent yields of 1-, 2-, and 3-NBA were 0.3 ± 0.1%, 10.5 ± 2.6 %, and 6.4 ± 1.3 %, respectively.

Versuche zur Oxidation von 1.5-Benzothiazepin — bzw. 1.5-Benzoxazepin- 2.4-3H.5H-dionen / Investigations Concerning Oxidation Reactions of 1,5-Benzthiazepin — and 1,5-Benzoxazepin- 2,4-3H,5H -diones

1984 ◽  
Vol 39 (3) ◽  
pp. 384-389 ◽  
Author(s):  
G. Kollenz ◽  
P. Seidler
Keyword(s):  
Acetic Acid ◽  
Malonic Acid ◽  
Reaction Pathway ◽  
Simple Synthesis ◽  
Oxidation Reactions ◽  
Acetic Acid Lead ◽  
Malonic Acid Derivatives

Attempts to oxidize the 1,5-benzothiazepin-2,4-3H,5H-dione (1) using NaNO2/Acetic acid lead to isolation of two ring contracted products, namely the 1,4-benzthiazin-derivatives 4 and 5. A reasonable reaction pathway concerning the formation of these compounds is discussed. A simple synthesis of 6-methyI-1,5-benzoxazepin-2,4-3H,5H-dione (13) is described, the transformation of which into the corresponding vic. trione fails, even using a great number of oxidizing procedures. In some cases so far unknown malonic acid derivatives 14, 15 and 16 can be obtained.

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