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Doctoral Thesis
DOI
10.11606/T.46.2015.tde-18092015-124232
Document
Author
Full name
Andreas Albert von Richthofen
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2015
Supervisor
Committee
Vitta, Claudio Di (President)
Bastos, Erick Leite
Cunha, Rodrigo Luiz Oliveira Rodrigues
Reis, Adriana Karla Cardoso Amorim
Santos, Alcindo Aparecido dos
Title in Portuguese
Benzo[5]radialenos como precursores de fluorenos e benzo[b]fluorenos
Keywords in Portuguese
Benzofluoreno
Benzo[5]radialeno
Diels-Alder
Fluoreno
Radialenos
Síntese orgânica
Abstract in Portuguese
Neste trabalho demonstramos a preparação de fluorenos e benzo[b]fluorenos por uma nova rota sintética, baseada na reação de Diels-Alder de derivados benzo[5]radialênicos. Para a preparação destes últimos investigamos diversas estratégias, partindo de p-benzoquinona e três dienos: 1,1-dimetoxiciclopentadieno, 6,6-dimetilfulveno e 6-acetoxifulveno. A partir de cada fulveno obtivemos um benzo[5]radialeno diferente, sendo que o derivado dimetilado se mostrou inerte como dieno em cicloadições. O benzo[5]radialeno derivado do 6-acetoxifulveno, reagiu com diversos dienófilos tais como p-benzoquinona, 2,3-dicloro-p-benzoquinona, 1,4-naftoquinona, N-metilmaleimida, acetilenodicarboxilato de dimetila, acrilato de metila, etc. Notamos uma alta quimiosseletividade entre os sistemas diênicos, pois obtivemos apenas adutos trans. Com alguns dienófilos observamos a formação de compostos aromatizados (formados pela eliminação de ácido acético que, para os casos pertinentes, foi regiosseletiva). Com dienófilos como acrilato de metila ou sulfinil-naftoquinonas, alta regiosseletividade foi observada. Tentamos explorar tais seletividades para a preparação de análogos da eucapsitriona. Os adutos de Diels-Alder obtidos constituem exemplos de derivados fluorênicos e benzo[b]fluorênicos que, ultimamente, têm recebido grande atenção tanto por aspectos estruturais como por apresentarem propriedades biológicas importantes
Title in English
Benzo[5]radialenes as precursors of fluorenes and benzo[b]fluorenes
Keywords in English
Benzofluorene
Benzo[5]radialene
Diels-Alder
Fluorene
Organic synthesis
Radialenes
Abstract in English
In this work we demonstrated the preparation of fluorenes and benzo[b]fluorenes by a new synthetic route, based on the Diels-Alder reaction of benzo[5]radialenes derivatives. For the preparation of the last we investigated several strategies starting from p-benzoquinone and three dienes: 1,1-dimethoxycyclopentadiene, 6,6-dimethylfulvene and 6-acetoxyfulvene. From each fulvene we obtained a different benzo[5]radialene, but the dimethylated one showed no reactivity in cycloadditions. The benzo[5]radialene prepared from 6-acetoxyfulvene reacted with several dienophiles such as p-benzoquinone, 2,3-dichloro-p-benzoquinone, 1,4-naphtoquinone, N-methylmaleimide, dimethyl acetylenedicarboxylate, methyl acrylate, etc. We noted a high quimiosselectivity between the dienic sub units since only trans adducts were obtained. With some dienophiles we observed the formation of aromatized compounds (formed by acetic acid elimination which, for suitable cases, was regiosselective). With dienophiles such as methyl acrylate or sulfinyl-naphtoquinones high regiosselectivity was observed. We tried to explore such selectivities to prepare eucapsitrione analogues. These Diels-Alder adducts are examples of fluorenic and benzo[b]fluorenic derivatives, compounds that have gained considerable attention due to structural and biological aspects.
 
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Publishing Date
2015-11-06
 
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