Preparation and transformations of allenic ketones and 3(2H)-furanones

1984 ◽  
Vol 62 (11) ◽  
pp. 2429-2434 ◽  
Author(s):  
Steven Wolff ◽  
William C. Agosta
Keyword(s):  
Double Bond ◽  
Carboxylic Acids ◽  
Good Yield ◽  
Osmium Tetroxide ◽  
Methyl Esters ◽  
Allene Oxide ◽  
Similar Treatment ◽  
Ruthenium Tetroxide ◽  
Swern Oxidation ◽  
Villiger Oxidation

Swern oxidation of allenic alcohols 7 and 10 gives the corresponding ketones 3 and 12. Reaction of 3 with ruthenium tetroxide yields the stable acyl ketene 17 and the acyloxy α-diketone 20 as well as pivalil (4). Formation of 20 by way of the 3(2H)-furanone 22 is suggested, since oxidation of 3 and 12 with osmium tetroxide followed by dehydration provides the corresponding furanones 22 and 26 in good yield. Epoxidation of 3 furnishes some 20 as well as 27 and 29, the first stable keto allene oxide and bisepoxide, respectively. On thermolysis 27 rearranges to furanone 22. The double bond of 22 is cleaved by peracid to form 20; similar treatment of 31a, b leads to cleavage of the double bond accompanied by Baeyer–Villiger oxidation, with formation of the carboxylic acids corresponding to methyl esters 33a, b as the major products.

Model Compounds Related to Saquayamycin. Attempts to Oxygenate the A/B Ring Junction

2002 ◽  
Vol 55 (5) ◽  
pp. 343 ◽  
Author(s):  
M. A. Apponyi ◽  
J. H. Bowie ◽  
B. W. Skelton ◽  
A. H. White
Keyword(s):  
Double Bond ◽  
Maleic Anhydride ◽  
Good Yield ◽  
Ring Opening ◽  
Diels Alder ◽  
Aromatic System ◽  
Model Compounds ◽  
Similar Treatment ◽  
Ring Junction

The aim of this project was to attempt to find a method for introducing the cis-dihydroxyl substitution at the A/B-ring junction of model compounds related to the saquayamycins. The Diels-Alder reactions of maleic anhydride and bromomaleic anhydride with 5,5-dimethyl-3-vinylcyclohexa-1,2-dienyl acetate gave the two required endo-adducts in good yield, namely (octahydrobenzo[e]isobenzofuran-9-yl acetate (6) and (octahydrobenzo[e]isobenzofuran-9-yl acetate (9). Each of these was converted into the B-ring mono-epoxide, namely (H-benzo[e]oxireno-2,3-furan-1-yl acetate (7) and a mixture of two racemic diastereoisomers of 9a-bromo-3,3-dimethyl-7,9-dioxoperhydrobenzo[e]oxi- reno[2,3-f]isobenzofuran-1-yl acetate (12), respectively. It was then hoped to deprotonate both (7) and (12) at the 9a position in order to effect migration of the 8,9 double bond to the 9,9a position. Reaction of (7) with a mild base (pyridine) did not effect any reaction. Similar treatment of (12) did remove the 9a proton, but it also effected ring opening of the epoxide, followed by dehydration and dehydrobromination to give an excellent (but unwanted) yield of the aromatized system (±)-7,7-dimethyl-1,3-dioxo-1,3,5,7-tetrahydrobenzo (e]isobenzofuran-9-yl acetate. Dehydrobromination of (9), and deprotonation of the 9a position, similarly formed the aromatic system (e]isobenzofuran-9-yl acetate (11) in good yield.

Efficient CDI/CH3SO3H -Catalyzed, Microwave-Assisted Synthesis of 2-Substituted Benzothiazoles

2018 ◽  
Vol 16 (1) ◽  
pp. 34-39
Author(s):  
Yao-Wei Li ◽  
Pei-Ming Zhang ◽  
Rui Li ◽  
Yan Bai ◽  
Yu Yu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Carboxylic Acids ◽  
1H Nmr ◽  
Good Yield ◽  
Microwave Assisted Synthesis ◽  
Synthetic Method ◽  
Benzothiazole Derivatives ◽  
Microwave Assisted ◽  
Highly Effective

CDI combined with CH3SO3H was found to be highly effective for the cyclization of 2-aminothiophenol derivatives with carboxylic acids under MW condition. Fourteen benzothiazole derivatives were synthesized in good yield and their structures were characterized by 1H-NMR, 13CNMR, IR and mass spectrometry. This simple, rapid synthetic method is believed to provide a useful process for the synthesis of 2-substituted benzothiazole compounds.

scholarly journals Synthesis of a sucrose dimer with enone tether; a study on its functionalization

2014 ◽  
Vol 10 ◽  
pp. 1246-1254 ◽  
Author(s):  
Zbigniew Pakulski ◽  
Norbert Gajda ◽  
Magdalena Jawiczuk ◽  
Jadwiga Frelek ◽  
Piotr Cmoch ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Double Bond ◽  
Carbonyl Group ◽  
Osmium Tetroxide ◽  
Cd Spectroscopy ◽  
Allylic Alcohol ◽  
Circular Dichroïsm

The reaction of appropriately functionalized sucrose phosphonate with sucrose aldehyde afforded a dimer composed of two sucrose units connected via their C6-positions (‘the glucose ends’). The carbonyl group in this product (enone) was stereoselectively reduced with zinc borohydride and the double bond (after protection of the allylic alcohol formed after reduction) was oxidized with osmium tetroxide to a diol. Absolute configurations of the allylic alcohol as well as the diol were determined by circular dichroism (CD) spectroscopy using the in situ dimolybdenum methodology.

scholarly journals Propylphosphonic acid anhydride–mediated amidation of Morita–Baylis–Hillman–derived indolizine-2-carboxylic acids

2021 ◽  
pp. 174751982098715
Author(s):  
Khethobole C Sekgota ◽  
Michelle Isaacs ◽  
Heinrich C Hoppe ◽  
Ronnett Seldon ◽  
Digby F Warner ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Coupling Agent ◽  
Methyl Esters ◽  
Acid Anhydride

Propylphosphonic acid anhydride has been successfully used as a coupling agent in the synthesis of a series of indolizine-2-carboxamido derivatives from indolizine-2-carboxylic acid and its 3-acetylated analogue. The acid substrates were obtained by saponification of the corresponding methyl esters produced, in turn, selectively and efficiently, by time-controlled cyclisation of a single Morita–Baylis–Hillman adduct. Various amino and hydrazino compounds with medicinal potential have been used to prepare indolizine-2-carboxamido and hydrazido derivatives.

The reaction of carboxylic acids with epoxides using lithium naphthalenide

1974 ◽  
Vol 27 (10) ◽  
pp. 2205 ◽  
Author(s):  
T Fujita ◽  
S Watanabe ◽  
K Suga
Keyword(s):  
Carboxylic Acids ◽  
Good Yield ◽  
Hydroxy Acids

Lithium naphthalenide reacts with carboxylic acids in the presence of diethylamine to give the α-anions of lithium carboxylates. Reaction of these anions with various epoxides gives the corresponding y-hydroxy acids in good yield. The γ-hydroxy acids easily cyclize to give γ-butyrolactones.

The reaction between 2,3-Diphenyl-2H-azirine and Phenyldiazomethane

1973 ◽  
Vol 26 (11) ◽  
pp. 2547 ◽  
Author(s):  
JH Bowie ◽  
B Nussey ◽  
AD Ward
Keyword(s):  
Double Bond ◽  
Good Yield ◽  
Alternative Synthesis

The reaction between 2,3-diphenyl-2H-azirine and phenyldiazomethane produces the stable 1-azido-1,2,3-triphenylprop-1-ene in good yield. The structure is confirmed by an alternative synthesis which indicates that the double bond has the E-configuration.

ChemInform Abstract: Catalytic Hydrogenation of Methyl Esters of Some 1H-Pyrazoline-3-carboxylic Acids.

ChemInform ◽  
2010 ◽  
Vol 41 (29) ◽  
pp. no-no
Author(s):  
V. A. Gorpinchenko ◽  
D. V. Petrov ◽  
S. S. Lozhkin ◽  
E. G. Galkin ◽  
V. A. Dokichev
Keyword(s):  
Carboxylic Acids ◽  
Catalytic Hydrogenation ◽  
Methyl Esters

ChemInform Abstract: Synthesis of 6-Acyl-7-aryl-4,7-dihydrotetrazolo[1,5-a]pyrimidine-5-carboxylic Acids and Their Methyl Esters

ChemInform ◽  
2008 ◽  
Vol 39 (10) ◽  
Author(s):  
V. L. Gein ◽  
L. F. Gein ◽  
E. P. Tsyplyakova ◽  
O. S. Panova
Keyword(s):  
Carboxylic Acids ◽  
Methyl Esters

Synthesis of 6-Acyl-7-aryl-4,7-dihydrotetrazolo[1,5-a]pyrimidine-5-carboxylic acids and their methyl esters

2007 ◽  
Vol 43 (9) ◽  
pp. 1382-1386 ◽  
Author(s):  
V. L. Gein ◽  
L. F. Gein ◽  
E. P. Tsyplyakova ◽  
O. S. Panova
Keyword(s):  
Carboxylic Acids ◽  
Methyl Esters
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