Silica gel-assisted preparation of 2,4,7-trihalobenzo[b]thiophenes and 4,7-dihalobenzo[b]thiophenes

Shinichi Mikami; Hiroki Tanaka; Hiroki Kishi; Shuhei Yoshida; Kozo Toyota

doi:10.1080/10426507.2019.1603725

Silica gel-assisted preparation of 2,4,7-trihalobenzo[b]thiophenes and 4,7-dihalobenzo[b]thiophenes

Shinichi Mikami, Hiroki Tanaka, Hiroki Kishi, Shuhei Yoshida, Kozo Toyota

SCI - Chemistry

Research output: Contribution to journal › Article › peer-review

2 Citations (Scopus)

Abstract

All 6 isomers of (bromo)(chloro)(iodo)benzo[b]thiophenes containing three different halogen atoms at the 2-, 4- and 7-positions were synthesized from the corresponding 2-(1-adamantylsulfanyl)-1,4-dihalo-3-(haloethynyl)benzene derivatives, through treatment with silica gel under thermal conditions. In contrast to our previous method using gold chloride catalyst, migration of adamantyl group did not occur in this method using silica gel. Moreover, by using this method, we synthesized 6 types of 4,7-dihalobenzo[b]thiophenes in 4 steps from 2-fluoro-3,6-dihalo-benzaldehydes in moderate to excellent overall yields, 42–82%.

Original language	English
Pages (from-to)	768-770
Number of pages	3
Journal	Phosphorus, Sulfur and Silicon and the Related Elements
Volume	194
Issue number	7
DOIs	https://doi.org/10.1080/10426507.2019.1603725
Publication status	Published - 2019 Jul 3

Keywords

Multihalo-benzo[b]thiophene
facile cyclization
fused thiophene
heterocycle
quasi T-shape molecular scaffold

ASJC Scopus subject areas

Biochemistry
Organic Chemistry
Inorganic Chemistry

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@article{167892d4bb904e5eb79ee1436460f2ac,

title = "Silica gel-assisted preparation of 2,4,7-trihalobenzo[b]thiophenes and 4,7-dihalobenzo[b]thiophenes",

abstract = "All 6 isomers of (bromo)(chloro)(iodo)benzo[b]thiophenes containing three different halogen atoms at the 2-, 4- and 7-positions were synthesized from the corresponding 2-(1-adamantylsulfanyl)-1,4-dihalo-3-(haloethynyl)benzene derivatives, through treatment with silica gel under thermal conditions. In contrast to our previous method using gold chloride catalyst, migration of adamantyl group did not occur in this method using silica gel. Moreover, by using this method, we synthesized 6 types of 4,7-dihalobenzo[b]thiophenes in 4 steps from 2-fluoro-3,6-dihalo-benzaldehydes in moderate to excellent overall yields, 42–82%.",

keywords = "Multihalo-benzo[b]thiophene, facile cyclization, fused thiophene, heterocycle, quasi T-shape molecular scaffold",

author = "Shinichi Mikami and Hiroki Tanaka and Hiroki Kishi and Shuhei Yoshida and Kozo Toyota",

year = "2019",

month = jul,

day = "3",

doi = "10.1080/10426507.2019.1603725",

language = "English",

volume = "194",

pages = "768--770",

journal = "Phosphorus, Sulfur and Silicon and the Related Elements",

issn = "1042-6507",

publisher = "Taylor and Francis Ltd.",

number = "7",

}

TY - JOUR

T1 - Silica gel-assisted preparation of 2,4,7-trihalobenzo[b]thiophenes and 4,7-dihalobenzo[b]thiophenes

AU - Mikami, Shinichi

AU - Tanaka, Hiroki

AU - Kishi, Hiroki

AU - Yoshida, Shuhei

AU - Toyota, Kozo

PY - 2019/7/3

Y1 - 2019/7/3

N2 - All 6 isomers of (bromo)(chloro)(iodo)benzo[b]thiophenes containing three different halogen atoms at the 2-, 4- and 7-positions were synthesized from the corresponding 2-(1-adamantylsulfanyl)-1,4-dihalo-3-(haloethynyl)benzene derivatives, through treatment with silica gel under thermal conditions. In contrast to our previous method using gold chloride catalyst, migration of adamantyl group did not occur in this method using silica gel. Moreover, by using this method, we synthesized 6 types of 4,7-dihalobenzo[b]thiophenes in 4 steps from 2-fluoro-3,6-dihalo-benzaldehydes in moderate to excellent overall yields, 42–82%.

AB - All 6 isomers of (bromo)(chloro)(iodo)benzo[b]thiophenes containing three different halogen atoms at the 2-, 4- and 7-positions were synthesized from the corresponding 2-(1-adamantylsulfanyl)-1,4-dihalo-3-(haloethynyl)benzene derivatives, through treatment with silica gel under thermal conditions. In contrast to our previous method using gold chloride catalyst, migration of adamantyl group did not occur in this method using silica gel. Moreover, by using this method, we synthesized 6 types of 4,7-dihalobenzo[b]thiophenes in 4 steps from 2-fluoro-3,6-dihalo-benzaldehydes in moderate to excellent overall yields, 42–82%.

KW - Multihalo-benzo[b]thiophene

KW - facile cyclization

KW - fused thiophene

KW - heterocycle

KW - quasi T-shape molecular scaffold

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U2 - 10.1080/10426507.2019.1603725

DO - 10.1080/10426507.2019.1603725

M3 - Article

AN - SCOPUS:85064682976

VL - 194

SP - 768

EP - 770

JO - Phosphorus, Sulfur and Silicon and the Related Elements

JF - Phosphorus, Sulfur and Silicon and the Related Elements

SN - 1042-6507

IS - 7

ER -

Silica gel-assisted preparation of 2,4,7-trihalobenzo[b]thiophenes and 4,7-dihalobenzo[b]thiophenes

Abstract

Keywords

ASJC Scopus subject areas

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