- A NOVEL SYNTHESIS OF (E)-3,7-DIMETHYL-2-OCTENE-1,8-DIOL SECRETED BY THE AFRICAN MONARCH USING THE RING-OPENING REACTION OF α-METHYL-β-PROPIOLACTONE
-
The regioselective ring-opening reaction of α-methyl-β-propiolactone with 3,3-ethylenedioxybutylmagnesium bromide in the presence of copper(I) catalyst afforded 2-methyl-6-oxoheptanoic acid, which was easily converted into (E)-3,7-dimethyl-2-octene-1,8-diol in good yield.
- Fujisawa, Tamotsu,Sato, Toshio,Kawara, Tatsuo,Noda, Atsunari
-
-
Read Online
- New synthesis of (±)-α-CMBHC and its confirmation as a metabolite of α-tocopherol (vitamin E)
-
There is currently interest in the metabolism of the various compounds which make up the vitamin E family, especially with regards to the possible use of vitamin E metabolites as markers of oxidative stress and adequate vitamin E supply. A number of vitamin E metabolites have been described to date and we have recently developed a method to extract and quantitate a range of vitamin E metabolites in human urine. During the development of this method a new metabolite of α-tocopherol was identified, which we tentatively characterised as 5-(6-hydroxy-2,5,7,8-tetramethyl-chroman-2-yl)-2-methyl-pentanoic acid (α-CMBHC). Here we describe the synthesis of α-CMBHC as a standard and confirm that it is a metabolite of α-tocopherol.
- Pope, Simon A.S.,Burtin, Guillaume E.,Clayton, Peter T.,Madge, David J.,Muller, David P.R.
-
-
Read Online
- Oxidative cleavage of cycloalkanones with dioxygen catalyzed by supported catalysts or homogeneous systems: Evidence for novel active ruthenium (II) and/or (III) species
-
α-Substituted cycloalkanones are oxidized to oxo-acids by low-nuclearity complexes (Cu2+ or [VO2] +/[VO]2+ - exchanged Nafion beads), or homogeneous systems with ruthenium acetate complexes and [Ru(H 2O)6] (tosylate)2 in dioxygen (0.1 MPa) at 55-60 °C. The catalytic procedures compare well with previously described systems involving homogeneous catalysis with copper (II) or polyoxometalates such as "H8[PMo7V5O40] ·aq". The results complement the widely used oxidative methods for ketone cleavage in cases when protons and transition metal salts are involved. A tentative dioxygenase mechanism, involving peroxygen species, is proposed for these reactions.
- Vennat, Maxence,Brégeault, Jean-Marie
-
-
Read Online
- Synthesis of 5- and 6-oxoalkanoic acids by copper(II) catalyzed oxidative cleavage of cycloalkanones with dioxygen
-
α-Substituted cycloalkanones are oxidized to oxo acids by the copper(II)/dioxygen/acetic acid/water system. This catalytic procedure compares well with the previously described systems involving vanadium precursors.
- Atlamsani,Bregeault
-
-
Read Online
- Visible Light-Driven, Copper-Catalyzed Aerobic Oxidative Cleavage of Cycloalkanones
-
A visible light-driven, copper-catalyzed aerobic oxidative cleavage of cycloalkanones has been presented. A variety of cycloalkanones with varying ring sizes and various α-substituents reacted well to give the distal keto acids or dicarboxylic acids with moderate to good yields.
- Xin, Hong,Duan, Xin-Hua,Yang, Mingyu,Zhang, Yiwen,Guo, Li-Na
-
p. 8263 - 8273
(2021/06/30)
-
- METHOD OF PRODUCING OPTICALLY ACTIVE (S)-7-HYDROXY-6-METHYLHEPTAN-2-ONE AND PRECURSOR THEREOF
-
Provided is a method capable of industrially producing optically active (S)-7-hydroxy-6-methylheptan-2-one and its precursor simply and efficiently. The production method, allows a R-body preferentially hydrolyzable Aspergillus microorganism-derived esterase to act on a 2-methyl-6-oxoheptanoate (II), to produce an optically active (S)-2-methyl-6-oxoheptanoate (III).
- -
-
Page/Page column 7-8
(2009/05/28)
-
- Sesterterpenoids from the sponge Sarcotragus sp.
-
Nineteen new sesterterpenoids and eight known compounds were isolated from the sponge Sarcotragus sp. collected from Soheuksan Island, Korea. The structures of these compounds were determined to be linear sesterterpenoids containing furan or related oxygenated functionalities on the basis of combined chemical and spectroscopic analyses. In addition, the configurations of several previously undetermined compounds were assigned. Several compounds exhibited moderate to major antibacterial activity (compounds 1-3, 17, 18) and cytotoxicity (3, 11, 12) against the K562 cell line and inhibitory activity against isocitrate lyase (6, 13).
- Wang, Nan,Song, Jueun,Kyoung, Hwa Jang,Lee, Hyi-Seung,Li, Xian,Oh, Ki-Bong,Shin, Jongheon
-
p. 551 - 557
(2008/12/23)
-
- An easy access to 2-oxohydrazones via electrophilic α-p-tolylhydrazonylation of ketone enolates with tert-butyl p-tolylazo sulfide
-
The title reaction conveniently furnishes, as the sole or main products, α-(p-tolylhydrazono)ketones or their N-methylderivatives (H+ or MeI quenching of the final mixture, respectively). Although the method fails with ketones having a secondary alkyl group bonded to the carbonyl, yields are otherwise more than satisfactory and particular interest is attached to the hydrazonylation of the methyl group in methyl ketones.
- Dell'Erba, Carlo,Novi, Marino,Petrillo, Giovanni,Tavani, Cinzia
-
p. 11239 - 11248
(2007/10/02)
-
- The Oxidation of Ketones with a Heteropolyacid, H5 and Dioxygen
-
Substituted cycloalkanones, 1-phenylalkanones, and open-chain ketones are oxidatively cleaved by the title compound under very mild conditions.
- Ali, Bassam El,Bregeault, Jean-Marie,Mercier, Jacqueline,Martin, Jacques,Martin, Claudine,Convert, Odile
-
p. 825 - 826
(2007/10/02)
-
- A New Synthesis of (E)-3,7-Dimethyloct-2-en-1,8-diol, a Component of the Hairpencil Secretion of African Monarch Butterfly
-
A facile synthesis of the title compound (1) has been achieved.The key intermediate, viz, the keto acid (6) is prepared via a novel route starting from the alkenol (2).Bromination of (2), and subsequent elaboration through the alkylation of diethyl malonate or propionic acid, affords the alkenoic acid (5) which upon oxidation with Jones' reagent in presence of Hg(OAc)2, provides 6.Following a well-established sequence of reactions, 6 is then transformed into 1.
- Joshi, N..N.,Mamdapur, V. R.,Chadha, M. S.
-
p. 238 - 240
(2007/10/02)
-
- Synthesis and Biological Activity of Zoapatanol Analogues
-
Dioxane analogues of the biologically active 3,6-oxido derivative (III) of zoapatanol (I) having substituents at the C-2 and C-5 positions, but lacking the ethano bridge, were evaluated for luteolytic and postcoital antifertility activity in the guinea pi
- Wani, Mansukh C.,Vishnuvajjala, B. Rao,Swain, William E.,Rector, Douglas H.,Cook, Clarence E.,et al.
-
p. 426 - 430
(2007/10/02)
-
- FACILE PREPARATION OF 2,6-DIMETHYL-2,6-TETRAHYDROPYRANCARBOLACTONE, A VERSATILE INTERMEDIATE FOR THE SYNTHESES OF (+/-)-FRONTALIN, (+/-)-CINENIC ACID, AND (+/-)-LINALOYL OXIDE
-
2,6-Dimethylcyclohexanone has been converted via its 2,6-dihydroxy derivative by base-catalyzed oxygenation to 2,6-dimethyl-2,6-tetrahydropyrancarbolactone which can be used as a key intermediate for the syntheses of the title natural products in racemic forms.
- Utaka, Masanori,Makino, Hiroshi,Oota, Yukito,Tsuboi, Sadao,Takeda, Akira
-
p. 2567 - 2570
(2007/10/02)
-
- REACTION BEHAVIOR OF CARBON-CARBON AND CARBON-HYDROGEN BONDS IN SUPER ACIDS. CARBOXYLATION OF ALKYL METHYL KETONES WITH CARBON MONOXIDE AND WATER
-
In a HF-SbF5 solution at -20 -ca.30 deg C under atmospheric pressure, ketones having alkyl groups with five or more carbon atoms underwent the reaction to give corresponding oxo carboxylic acids without any β-scission processes which occur readily in alkyl cations derived by protolysis of alkalnes with seven or more carbon atoms.Tertiary C-H bond located at δ or further away from the oxo group in the substrates could react exclusively to give (ω-1)-oxo-2,2-dimethyl carboxylic acids at -20 deg C.
- Yoneda, Norihiko,Sato, Haruhiko,Fukuhara, Tsuyoshi,Takahashi, Yukio,Suzuki, Akira
-
-