- Alkoxide-catalyzed ring expansion of 1,3-cyclobutanediones with aldehydes
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1,3-Cyclobutanediones (dialkyl ketene dimer) reacted with various aromatic aldehydes to give six-membered cyclic β-keto esters by using a catalytic amount of potassium ethoxide. Effects of alkoxide catalysts and spiro cyclic groups at the 2,4-positions of 1,3-cyclobutanediones were investigated.
- Yamazaki, Mizuki,Yoshimura, Tomoyuki,Matsuo, Jun-ichi
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supporting information
(2021/01/25)
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- Synthesis, structure and reactivity of some chiral benzylthio alcohols, 1,3-oxathiolanes and their S-oxides
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A series of amino acid-derived chiral benzylthio alcohols have been prepared and characterized. A chiral mercapto alcohol derived from S-leucine has been used to form three chiral 2,4-disubstituted 1,3-oxathiolanes. One of these has been oxidized to the S-oxide and another to the S,S-dioxide. The cis and trans isomers have been characterized by 1H NMR in each case and it appears that thermal epimerisation at C-2 is possible at the sulfoxide oxidation state. The X-ray structure of major trans diastereomer of 2-phenyl-4-isobutyl-1,3-oxathiolane S,S-dioxide shows an envelope conformation with oxygen at the flap and an internal angle at sulfur of just 93.8°. This compound fragments upon flash vacuum pyrolysis at 700°C to give SO2, benzaldehyde and 4-methylpent-1-ene.
- Aitken, R. Alan,Lightfoot, Philip,Thomas, Andrew W.
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p. 369 - 387
(2020/05/25)
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- METHOD FOR PRODUCING POLYALKYLENE GLYCOL DERIVATIVE HAVING AMINO GROUP AT END
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A method simply produces a narrowly distributed and high-purity polyalkylene glycol derivative having an amino group at an end without using a heavy metal catalyst. A method for producing a polyalkylene glycol derivative having an amino group at the end by reacting a compound represented by the general formula (V) with an alkylene oxide, then reacting a reaction product with an electrophile represented by the general formula (I), and deprotecting the obtained product without using a heavy metal: [in-line-formulae]RA3O(RA4O)k-1RA4O?M+??(V)[/in-line-formulae]wherein RA3 represents a linear; branched, or cyclic hydrocarbon group having 1 to 20 carbon atoms; RA4 represents an alkylene group having 2 to 8 carbon atoms; k represents an integer of 2 to 5; and M represents an alkali metal; wherein RA1a and RA1b each independently represent a protective group of the amino group, or one of RA1a and RA1b represents H and the other represents a protective group of the amino group, or RA1a and RA1b bind to each other to form a cyclic protective group, and the protective group is deprotectable without using a heavy metal; RA2 represents a linear, branched, or cyclic hydrocarbon group having 1 to 6 carbon atoms; and X represents a leaving group.
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Paragraph 0162-0164; 0232
(2016/07/05)
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- Preparation method for low residual granular sodium alkoxide or potassium alcoholate
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The invention provides a preparation method for low residual granular sodium alkoxide or potassium alcoholate. The method includes using sodium or potassium and alcohol as raw materials, mixing the mixture with a solvent, reacting in inert gas atmosphere by using a microwave heating method, and removing the residual alcohol and solvent in the presence of microwave after the reaction to get the granular sodium alkoxide or potassium alcoholate. The microwave frequency is 2450 +/- 50 MHz. The method can prepare sodium alkoxide or potassium alcoholate with low residual solvent, and the prepared sodium alkoxide or potassium alcoholate is large granular solid, so that the development from powdered product to granular product can be realized, and the problems of residual solvent and potential risk troubled human for a long time can be overcome.
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Paragraph 0029-0030
(2017/01/17)
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- Chelating agents for technetium-99M
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The present invention relates to a novel family of Technetium chelating agents (ligands) based upon amide and mercaptide donor groups.
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- Synthese et caracrerisation du α-hydroxy, ω-(4-N,N-dimethylaminophenyl)polystyrene
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To prepare polymers carrying a donor chromophore at one end and an acceptor chromophore at the other anionic initiators carrying the 4-N,N-dimethylaminophenyl group were synthesized by two different methods.These polymers were needed for the purpose of studying intramolecular cyclization via observation of exciplex formation.It was established that metal cleavage of appropriately substituted ethers was the most advantageous way to synthesize these functionalized initiators.These compounds provided vary reactive toward styrene, yielding quantitatively polymers bearing 4-(N,N-dimethylaminophenyl) groups at one end of the chain.At the othe r end of the chain, induced deactivation of the "living" sites by means of oxirane created a hydroxy function that could be used in a later step to attach various other groups.Attachment of pyrene to this end would lead to a system in which intramolecular exciples formation could occur.
- Beinert, Gerard,Winnik, Mitchell A.
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p. 1743 - 1746
(2007/10/02)
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