16872-93-8Relevant academic research and scientific papers
Decomposition of the crown ether ring in the reaction of K-, K+(15-crown-5)2 with oxetane
Grobelny, Zbigniew,Stolarzewicz, Andrzej,Maercker, Adalbert
, p. 283 - 286 (2000)
A cleavage of both oxacyclic rings occurs in the reaction of K-, K+(15-crown-5)2 with oxetane in tetrahydrofuran solution. Oxetane ring opening leads to the formation of organometallic compounds, which react with the crown molecule. Potassium methoxide, potassium n-propoxide as well as potassium tetra(ethylene glycoxide) vinyl ether are the main reaction products. It means that crown ether can act both as an activator and as a reagent under studied conditions.
METHOD FOR PRODUCING POLYALKYLENE GLYCOL DERIVATIVE HAVING AMINO GROUP AT END
-
Paragraph 0162-0164; 0232, (2016/07/05)
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.
Concerning the Products of the Reaction of Methyl Bromide and Ethyl Bromide with Potassium Hydroxide in Aqueous Methanolic Solutions and the Progress of this SN2-Reaction
Friedrich,Sonnefeld,Jansen
, p. 73 - 80 (2007/10/03)
Investigations of the reaction of methyl bromide and ethyl bromide with potassium hydroxide in methanolic and aqueous methanolic solutions show that the main products of these reactions are dimethyl ether and ethylmethyl ether. The reaction rates measured in methanolic or aqueous methanolic solutions are the same whether potassium hydroxide or potassium methoxide are used. These results are caused by an equilibrium between hydroxide and methoxide ions with which we could establish the equilibrium constant near 0.6. This means that a solution of sodium hydroxide c=0.1 moll-1 in methanol contains roughly 99.8% of methoxide ions. The reaction rates in methanolic as well as in aqueous methanolic solutions are strict second order. The reaction rate measured at several temperatures permitted the calculation of EA≠, ΔH≠, ΔS≠ and ΔG≠. Furthermore the kinetic investigations show that the nucleophilicity of methoxide ions is lower compared to hydroxide ions. The calculation of the Swain-Scott-parameter n results in a nucleophilicity scale in order to methoxide, hydroxide, ethoxide ions. The kinetic investigations of the reaction of ethyl bromide with methoxide and hydroxide ions in methanolic solutions demonstrate that at high temperatures the rate constant of methoxide ions is higher than that of hydroxide ions. The opposite case can be observed at lower temperatures. At the temperature of 20°C the rate constants of both reactions are equal. This is to do with the isokinetic effect which one is rarely able to observe at room temperatures.
