Nucleophilic Opening of the Oxirane Ring with Tetraalkylammonium Salt Anions in the Presence of Proton Donors

2021 ◽  
Vol 57 (4) ◽  
pp. 524-531
Author(s):  
S. G. Bakhtin ◽  
E. N. Shved ◽  
M. A. Sinelnikova ◽  
Yu. N. Bespalko
Keyword(s):  
Oxirane Ring ◽  
Tetraalkylammonium Salt ◽  
Proton Donors

Some 1-substitution derivatives of 4-aryl-2,3-dihalogeno-1-naphthols

1984 ◽  
Vol 49 (1) ◽  
pp. 110-121 ◽  
Author(s):  
Jiří Křepelka ◽  
Drahuše Vlčková ◽  
Milan Mělka
Keyword(s):  
Thionyl Chloride ◽  
Oxirane Ring ◽  
Secondary Amines ◽  
Two Phase ◽  
Lytic Effect ◽  
Primary And Secondary Amines ◽  
Phase Medium ◽  
Chloro Derivatives ◽  
Derivatives Of

Alkylation of derivatives of 4-aryl-1-naphthols (I-V) by 2,3-epoxypropyl chloride in methanolic sodium hydroxide gave epoxy derivatives VI, VIII, IX, XI and XII, apart from products of cleavage of the oxirane ring, VII and X. Analogous alkylation of compounds I, IV and V by 2-(N,N-diethylamino)ethyl chloride hydrochloride in a two-phase medium afforded basic ethers XIII to XV. The cleavage of the oxirane ring in compound VI by the action of primary and secondary amines, piperidine and substituted piperazines led to compounds XVI-XXIV. Reaction of thionyl chloride with compounds XXI, XXII and XXIV gave chloro derivatives XXV-XXVII.Exposure of compound XXII to 4-methylbenzenesulfonyl chloride produced compound XXVIII, retaining the secondary alcoholic group. In an antineoplastic screening in vivo none of the compounds prepared had an appreciable activity. Compound XVII, being an analogue of propranolol, was used in the test of isoproterenolic tachycardia, and showed a beta-lytic effect comparable with that of propranol.

Mechanism of acid cleavage of some steroid epoxides. Competition between neighboring group participation and external nucleophile attack

1982 ◽  
Vol 47 (1) ◽  
pp. 124-129 ◽  
Author(s):  
Pavel Kočovský ◽  
František Tureček ◽  
Václav Černý
Keyword(s):  
Perchloric Acid ◽  
Cyclic Ether ◽  
Oxirane Ring ◽  
Neighboring Group ◽  
Group Participation ◽  
Acid Cleavage ◽  
Neighboring Group Participation

The mechanism of perchloric acid cleavage of epoxides I and II was established on the basis of experiments using H2 18O. The 2α,3α-epoxide I gave two products: the cyclic ether V (60%) arising by 5(O)n participation of the 19-acetoxyl and the diol VI (40%). The latter compound is formed by two mechanisms: 1) By direct cleavage of the oxirane ring with H2 18O as external nucleophile and 2) by 7(O)π,n participation via the ion III. Under the same conditions the 5α,6α-epoxide II yielded two diols: The diequatorial diol VIII (96%) arising by 6(O)π,n participation and the diaxial diol IX which is again formed by both direct cleavage of the oxirane ring with H2 18O and by 7(O)π,n participation via the intermediate ion X. The competition of several mechanisms is discussed.

An analysis of the factors contributing to the regioselectivity observed in the opening of oxiranes

1980 ◽  
Vol 58 (3) ◽  
pp. 302-306 ◽  
Author(s):  
Margaret M. Kayser ◽  
Peter Morand
Keyword(s):  
Oxygen Atom ◽  
Ring Opening ◽  
Oxirane Ring ◽  
Epoxide Ring ◽  
Acid Base ◽  
Epoxide Ring Opening ◽  
Soft Acid ◽  
Hsab Theory

The regioselectivity of epoxide ring opening can be analyzed in terms of hard–soft acid–base (HSAB) theory. The coordination of the hard acid with the oxygen atom of the oxirane ring produces a "pulling effect" which determines the direction of the ring opening. In the absence of a strong "pulling effect" the "pushing effect" of the approaching base is examined and the consequences of relative softness or hardness of the nucleophile on the regioselectivity of the ring opening are discussed.

The intramolecular opening of the oxirane ring in butyl 4,5-anhydro-3,6-dideoxyhexaldonate

1985 ◽  
Vol 50 (25) ◽  
pp. 5360-5362 ◽  
Author(s):  
Marek Chmielewski ◽  
Piotr Guzik ◽  
Bogumila Hintze ◽  
Wlodzimierz M. Daniewski
Keyword(s):  
Oxirane Ring

Are amines basic or nucleophilic catalysts for oxirane ring opening by proton-donating nucleophiles?

2016 ◽  
Vol 57 (1) ◽  
pp. 47-51 ◽  
Author(s):  
S. G. Bakhtin ◽  
E. N. Shved ◽  
Yu. N. Bespal’ko
Keyword(s):  
Ring Opening ◽  
Oxirane Ring ◽  
Nucleophilic Catalysts

Formation and Electrolytic Dissociation of the Potassium Compounds of Monohydronaphthalene and Monohydroanthracene

1970 ◽  
Vol 25 (2) ◽  
pp. 176-178 ◽  
Author(s):  
K. K. Brandes ◽  
R. J. Gerdes
Keyword(s):  
Aromatic Hydrocarbons ◽  
High Purity ◽  
Electrolytic Dissociation ◽  
Proton Donors

The molar heats of dissociation of the potassium compounds of monohydronaphthalene and monohydroanthracene (MH⊝K⊕) in 1,4-dioxane have been determined. Furthermore it has been shown that even high-purity solvents will eventually act as proton donors for dinegative ions of aromatic hydrocarbons.

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