Allenic Products Research Articles

Allenic thioester hydration activity of beef liver crotonase

The conversion of 3-decynoyl- N-acetylcysteamine to 2,3-decadienoyl- N-acetylcysteamine catalyzed by a homogeneous mammalian liver enzyme has recently been described (F. M. Miesowicz and K. E. Bloch, Biochem. Biophys. Res. Commun. 65, 331 (1975). The allenic thioester product, however, does not accumulate in crude liver extracts suggesting that it undergoes further enzymatic transformation. Evidence is presented here that crotonase (enoyl Coenzyme A hydratase) catalyzes the hydration of allenic thioesters to the corresponding β-keto thioesters which are normal intermediates in the β-oxidation of fatty acids.

Reaktionen an Allencarotinoiden 2

AbstractThe conversion of the allenic end group 1 on HCl/CHCl3 treatment to the acetylenic 2 resp. to the chlorinated end group 3 previously reported has been confirmed using neoxanthin (4a) and its diacetate (4b). Analogous HBr treatment provided the corresponding brominated end group. Chemical and spectroscopical evidence for the position of the halogen atom at C(7) is given.Transformation to allenic anhydro products and acetylenic products on treatment of neoxanthin diacetate (4b) with phosphorous oxychloride in pyridine, as well as dehydration and chlorine substitution of neoxanthin (4a) are reported. These results are consistent with previous observations on related carotenoids.

Reactivite des propargyl- et allenyl-boronates de dibutyle vis-a-vis des derives carbonyles : II. Generalisation et etude des divers facteurs reactionnels

Ketones react with dibutyl allenylboronate to give borates. Except acetone, acetophenone and cyclohexanone which give only acetylenic compounds, condensation of all ketones studied results in the formation of a mixture of acetylenic and allenic borates, the ratio of which depends on the bulkiness of the ketone, the proportions of reactants used and the temperature and solvent. These condensations are under kinetic control and the allenic product has an unrearranged structure.

ChemInform Abstract: VACUUM ULTRAVIOLET PHOTOLYSIS OF TRIMETHYLETHYLENE

Chemischer InformationsdienstVolume 5, Issue 15 Preparative Organic Chemistry ChemInform Abstract: VACUUM ULTRAVIOLET PHOTOLYSIS OF TRIMETHYLETHYLENE GUY J. COLLIN, GUY J. COLLINSearch for more papers by this authorCHRISTIAN M. GAUCHER, CHRISTIAN M. GAUCHERSearch for more papers by this author GUY J. COLLIN, GUY J. COLLINSearch for more papers by this authorCHRISTIAN M. GAUCHER, CHRISTIAN M. GAUCHERSearch for more papers by this author First published: April 16, 1974 https://doi.org/10.1002/chin.197415122Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume5, Issue15April 16, 1974 RelatedInformation

Reaction of dimethylvinylidene with γγ-dimethylallyl methyl sulphide. Synthesis of 2,5,5-trimethylhepta-2,6-dien-4-one (artemisia ketone)

The [2,3] sigmatropic rearrangement of the sulphonium ylide derived from the title reaction, followed by hydrolysis of the allenic thioether product affords artemisia ketone (6).

Some recent advances in the synthesis of carotenoids.

Abstract