カサシマ　ヨシオ   YOSHIO KASASHIMA   笠嶋　義夫    所属   千葉工業大学  創造工学部 教育センター（創造工学部）    職種   教授
言語種別	英語
発行・発表の年月	2018/10
形態種別	学術雑誌
査読	査読あり
標題	Umpolung cyclization reaction of N-cinnamoylthioureas in the presence of DBU
執筆形態	共著
掲載誌名	Organic & Biomolecular Chemistry
掲載区分	国外
出版社・発行元	Royal Society of Chemistry
巻・号・頁	16,pp.7910-7919
著者・共著者	Rei Saito, Naohiro Uemura, Hiroki Ishikawa, Akina Magara, Yasushi Yoshida, Takashi Mino, Yoshio Kasashima and Masami Sakamoto
概要	AbstractA novel regioselective cyclization reaction of N-cinnamoylthioureas leading to six- or five-membered heterocyclic compounds was developed. N-Cinnamoylthioureas in the presence of trifluoroacetic acid (TFA) underwent the well-established intramolecular cycloaddition reaction to give 2-imino-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-ones in good yields. On the other hand, the reaction with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) proceeded in an unprecedented umpolung cyclization fashion to afford five-membered 2-imino-1,3-thiazolidin-4-ones and/or 2-thioxoimidazolidine-4-ones. The reaction was considered to occur via a cycloadduct of DBU with the cinnamoyl moiety followed by intramolecular attack of the thiourea group.
DOI	10.1039/C8OB02066C
ISSN	1477-0520