Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Mechanism of С-Н cyclization of alkynylanthraquinones into thienoanthraquinones with the participation of sodium sulfide. / Fedenok, Lidiya; Dultsev, Fedor; Barabanov, Igor и др.
в: Tetrahedron, Том 73, № 44, 02.11.2017, стр. 6334-6340.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Mechanism of С-Н cyclization of alkynylanthraquinones into thienoanthraquinones with the participation of sodium sulfide
AU - Fedenok, Lidiya
AU - Dultsev, Fedor
AU - Barabanov, Igor
AU - Polyakov, Nikolay
PY - 2017/11/2
Y1 - 2017/11/2
N2 - The CH-cyclization of alkynyl-9,10-anthraquinones 1 into thienoanthraquinones 2 is shown to be initiated by the neutral S2 molecule and not by the sulfide anion as it is assumed in the existing model of CH-cyclization with the nucleophiolic substitution of H. The formation of S2 takes place in the reaction medium due to the partial reduction of the substrate 1 by Na2S into the corresponding anthrahydroquinone, which is inactive in the main reaction. We present a new cyclization mechanism with the key stage involving the electrophilic displacement of H, which results in the formation of the reaction product 2 and elimination of S. In the reaction medium atomic sulfur is transformed into S2, which initiates the next cyclization act. This determines the chain nature of cyclization with the participation of S2. Within this model, the route to increase the yield of target thienoanthraquinones is proposed through the introduction of a neutral quinone able to generate S2 by means of easy reduction.
AB - The CH-cyclization of alkynyl-9,10-anthraquinones 1 into thienoanthraquinones 2 is shown to be initiated by the neutral S2 molecule and not by the sulfide anion as it is assumed in the existing model of CH-cyclization with the nucleophiolic substitution of H. The formation of S2 takes place in the reaction medium due to the partial reduction of the substrate 1 by Na2S into the corresponding anthrahydroquinone, which is inactive in the main reaction. We present a new cyclization mechanism with the key stage involving the electrophilic displacement of H, which results in the formation of the reaction product 2 and elimination of S. In the reaction medium atomic sulfur is transformed into S2, which initiates the next cyclization act. This determines the chain nature of cyclization with the participation of S2. Within this model, the route to increase the yield of target thienoanthraquinones is proposed through the introduction of a neutral quinone able to generate S2 by means of easy reduction.
KW - Alkynyl-9,10-anthraquinones
KW - Heterocyclization
KW - Mechanism
KW - Sodium sulfide
KW - Thienoanthraquinones
KW - ACETYLENIC DERIVATIVES
KW - ANTHRAQUINONE
KW - DENSITY
KW - SULFUR
UR - http://www.scopus.com/inward/record.url?scp=85030025841&partnerID=8YFLogxK
U2 - 10.1016/j.tet.2017.09.023
DO - 10.1016/j.tet.2017.09.023
M3 - Article
AN - SCOPUS:85030025841
VL - 73
SP - 6334
EP - 6340
JO - Tetrahedron
JF - Tetrahedron
SN - 0040-4020
IS - 44
ER -
ID: 9872437