- Stereocontrolled Route to 2,3,5-Trisubstituted Tetrahydrofurans. Intermediates for the Total Synthesis of Polyether Antibiotics.
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The stereoselective synthesis of diastereomers of 2,3,5-trisubstituted tetrahydrofurans has been accomplished by Lewis acid catalyzed acetal rearrangement.The reaction sequence starts with 4,7-dihydro-1,3-dioxepins 4, which are isomerized to 4,5-dihydro-1,3-dioxepins 6.The key step of the procedure is the stereocontrolled rearrangement of these mixed alkyl vinyl acetals 6, followed by reduction. 2,3,5-Trisubstituted tetrahydrofurans are of general interest for the synthesis of polyether antibiotics.
- Frauenrath, Herbert,Runsink, Jan
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- FUNCTIONAL OLIGOMERS AND FUNCTIONAL POLYMERS INCLUDING HYDROXYLATED POLYMERS AND CONJUGATES THEREOF AND USES THEREOF
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The present disclosure describes functional oligomers or functional polymers. The functional oligomers or functional polymers may contain functional groups, e.g., -OH and/or -CHO. The functional oligomers or functional polymers may be obtained from hydrolyzing certain copolymers and may be soluble in commercially available solvents. The copolymers may be thermosetting polymers. The functional oligomers and functional polymers may be useful for recycling thermosetting polymers and may be useful as starting materials for preparing additional oligomers or polymers.
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Page/Page column 112-113
(2021/05/21)
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- Synthesis and cytotoxic properties of some cyclic acetals of diols and their dichlorocyclopropyl derivatives
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Cyclic acetals of ethylene glycol, cis-but-2-ene-1,4-diol and their dichlorocyclopropyl derivatives were synthesized. Compounds simultaneously containing the gem-dichlorocyclopropane and 1,3-dioxacycloalkane cycles are shown to exhibit cytotoxic activity against the HEK293, SH-SY5Y, HepG2, MCF-7, A549, and Jurkat cell lines. The obtained results open up prospects for further studies of antitumor activity of 2-(2,2-dichlorocyclopropyl)-2-ethyl-1,3-dioxolane.
- Raskil’dina,Kuzmina, U. Sh.,Dzhumaev, Sh. Sh.,Borisova, Yu. G.,Ishmetova,Vakhitova, Yu. V.,Zlotskii
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p. 475 - 478
(2021/04/09)
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- A continuous preparation of 2-isopropyl -1,3-dioxo-5-cycloheptaene method and device
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The invention relates to a method and equipment for continuously preparing 2-isopropyl-1,3-dioxo-5-cycloheptene. The method comprises the steps of feeding 1,4-butenediol and a catalyst after being premixed, and isobutyraldehyde simultaneously into a tubular reactor I for performing a semi-aldolization under a continuous operation condition, and then feeding a reaction mixture immediately into a tubular reactor II for performing a dehydration aldolization; and after the reaction is ended, feeding the mixture into an automatic demixer to separate a water layer, feeding an oil layer in a rectifying tower for removing the isobutyraldehyde as a front cut fraction, and rectifying out a normal cut fraction of 100-102 DEG C from a kettle residue at a pressure of 10KPa to obtain the 2-isopropyl-1,3-dioxo-5-cycloheptene. The tubular reactor provided by the invention is divided into two sections, a spiral guide metal wire is arranged in the first section of reactor, a corrugated plate filler is arranged in the second section of reactor, a sleeve is arranged outside the reactor, hot water or steam is introduced into the sleeve for performing heating, an outlet of the reactor is communicated with the demixer through a pipeline after releasing pressure so as to perform continuous demixing, and the oil layer enters a continuous rectifying device to rectify a qualified product. The method is simple in process, stable in reaction process, short in reaction time and less in side reactions.
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Paragraph 0034-0036
(2017/02/17)
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- Monofunctional metathesis polymers via sacrificial diblock copolymers
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(Chemical Equation Presented) A small price to pay: The second block of a diblock copolymer is "sacrificed" in order to leave behind a monofunctionalized metathesis polymer with a hydroxy end group. By incorporation of a dioxepine unit into the copolymer, a breaking point is created between the block to be end-functionalized and the block to be sacrificed.
- Hilf, Stefan,Berger-Nicoletti, Elena,Grubbs, Robert H.,Kilbinger, Andreas F. M.
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p. 8045 - 8048
(2007/10/03)
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