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Showing papers on "Enone published in 1970"


Journal ArticleDOI
TL;DR: Dglucal is selectively oxidised to the corresponding enone with a 60-80% yield by Fetizon's reagent (Ag2CO3-celite) as mentioned in this paper.
Abstract: D-glucal is selectively oxidised to the corresponding enone with a 60–80% yield by Fetizon's reagent (Ag2CO3-celite).

21 citations


Journal ArticleDOI
TL;DR: In this article, a convenient route from abieta-8,11,13-trien-18-oic acid to Abieta5,8, 11, 13-tetraen-3-one was developed involving selective epoxidation of the alkene mixture, obtained by oxidative decarboxylation of the acid with lead tetraacetate.
Abstract: A convenient route from abieta-8,11,13-trien-18-oic acid (10) to abieta5,8,11,13-tetraen-3-one (27) has been developed involving selective epoxidation of the alkene mixture (2) obtained by oxidative decarboxylation of the acid with lead tetraacetate. Treatment of the 3a,4a-epoxide (9) with lithium diethylamide gives a quantitative yield of the allylic alcohol (19). Brief treatment of this allylic alcohol with N-lithioethylenediamine gives the α, β-unsaturated alcohol (25), which on oxidation affords the enone (24). Methylation of the latter compound with methyl iodide and potassium t-butoxide in t-butanol yields abieta-5,8,11,13-tetraen-3-one (27) in 43% overall yield from the alkene mixture (2). Other reactions of the 3α, 4α-epoxide (9) are reported and discussed.

12 citations


Journal ArticleDOI
TL;DR: The synthesis of 3.2 and 4-Methylcyclopent-2-enone has been studied in this article. But it has not yet been applied to synthetic drugs.
Abstract: 2- and 4-Methylcyclopent-2-enone, and the ethylene acetal (16) of 3-formyl-4-methylcyclopent-2-enone have been synthesized.

10 citations


Journal ArticleDOI
TL;DR: In the presence of an acid, N-nitrosopiperidine photolytically adds to conjugated dienes to give 1:1 adducts in excellent yield as discussed by the authors.
Abstract: In the presence of an acid, N-nitrosopiperidine photolytically adds to conjugated dienes to give 1:1 adducts in excellent yield. While the major products are the syn- and anti-isomers of piperidino...

7 citations


Journal ArticleDOI
TL;DR: In this article, the cyclization of the dienedione 5 with strong acid was studied and a new isomeric des-A-androst-9-en-5, 17-diones (16, 17 and 20) was determined by chemical and spectroscopic methods.
Abstract: In a search for a new and efficient synthesis of the compound 7, the cyclization of 5 (obtained by a Michael-reaction from 3 and 4) was studied. Treatment of 5 with strong acid furnished the known dienedione 8. Mild acidic conditions gave the bridged alcohol 9 and other, unidentified products, rather than the desired enone 6. Under basic conditions, 5 did not cyclize to 6, but underwent retro-Michael reaction. Attempts were then made to convert the dienedione 8 to the 14α-enone 19. However, both catalytic hydrogenation and lithium-ammonia reduction of 8 yielded mainly 14β-products. In some hydrogenation experiments, isomerization of the dienedione 8 to the phenols 13 (major) and 14 (minor) occurred. The stereochemistry of the new isomeric des-A-androst-9-en-5, 17-diones (16, 17 and 20) was determined by chemical and spectroscopic methods.

7 citations


Journal ArticleDOI
TL;DR: The 2, 5-diene-1, 7-dione 12 rearranges photochemically to the cyclopentenonyl-cyclopropyl ketone 13 as discussed by the authors.
Abstract: The 2, 5-diene-1, 7-dione 12 rearranges photochemically to the cyclopentenonyl-cyclopropyl ketone 13. Dienone 12 does not emit phosphorescence at 78K. Sensitization and quenching experiments indicate that the photorearrangement occurs in an excited triplet state with ET between ca. 61–65 kcal/mol according to sensitization data, and between ca. 54–58 kcal/mol according to quenching results. By comparison, the 2, 5-dienone 1 behaves similarly with respect to sensitization and quenching of its photorearrangement [3] (indicating ET 61 kcal/mol for its photorearrangement, respectively. It is concluded that the triplet energy of the reactive state of compound 12 extends either over the two enone groups involving strong interaction or is localized on the ring A enone only. Photoproduct 13 rearranges further to the stereoisomer 14 on direct excitation and sensitization with acetophenone. Thioxanthone as triplet sensitizer and naphthalene as triplet quencher are ineffective. The reverse isomerization process, i.e.14 13, is not observed.

7 citations


Journal ArticleDOI
TL;DR: In this article, eucarvone adsorbed on silica gel or in trifluoroethanol gives, in addition to the two expected products (IIa and IIb), the bicyclo[4,1,0]enone (V), which subsequently undergoes[1,3]sigmatropic photorearrangement to dehydrocamphor (IV) and a cyclobutanone (VI).
Abstract: Irradiation of eucarvone (I) adsorbed on silica gel or in trifluoroethanol gives, in addition to the two expected products (IIa and IIb), the bicyclo[4,1,0]enone (V), which subsequently undergoes[1,3]sigmatropic photorearrangement to dehydrocamphor (IV) and a cyclobutanone (VI).

4 citations


Journal ArticleDOI
TL;DR: The crystal structures of 3-bromo, 3-chloro-, and 4-Bromo-2′-nitro-chalcone have been solved from 0kl, partial three-dimensional, and zonal data respectively.
Abstract: The crystal structures of 3-bromo-, 3-chloro-, and 4-bromo-2′-nitrochalcone have been solved from 0kl, partial three-dimensional, and zonal data respectively. Unlike other chalcones so far analysed and 4-bromo-2′-nitro-chalcone the first two compounds crystallise in the transoid conformation of the enone system. 3-Chloro- and 4-bromo-2′-nitrochalcone exhibit short oxygen⋯carbon contacts (2·58 and 2·64 A) between the nitro- and carbonyl groups.

4 citations


Journal ArticleDOI
TL;DR: In this article, a Robinson-type ring closure was used to synthesize 4-ethylcyclohex-2-enone by a mixture of conjugated and non-conjugated ketones.
Abstract: An attempt to synthesize 4-ethylcyclohex-2-enone by a Robinson-type ring closure gave a mixture of conjugated and non-conjugated ketones from which the conjugated isomer was isolated. 4-Ethylcyclohex-3-enone on treatment with acid yielded the same mixture of ketones. Pyrolysis of 4-carboxy-4-vinylheptanedioic acid with barium carbonate formed 4-ethylidenecyclohexanone.

3 citations


Journal ArticleDOI
TL;DR: In this article, enamines have been isolated from the reaction of 2-hydroxy-3-methylcyclopent-2-enone with aromatic amines and their structures have been elucidated.
Abstract: Enamines have been isolated from the reaction of 2-hydroxy-3-methylcyclopent-2-enone with aromatic amines and their structures have been elucidated. The enamine from the title compound and 2-aminoacetophenone can be cyclised to 2,9-dimethyl-1H-cyclopenta[b]quinolin-3(2H)-one. 2-Benzyl-3-methylcyclopent-2-enone has been synthesised.

2 citations



Journal ArticleDOI
TL;DR: In this article, the photodimerization of 3-methylcyclohex-2-enone yields two dimers whose structures have been determined as head-to-tail anti, (1) and headto-head anti (2).
Abstract: The photodimerization of 3-methylcyclohex-2-enone yields two dimers whose structures have been determined as head-to-tail anti, (1) and head-to-head anti, (2).