在 EtOH-H 2 O 存在下腈与 P 2 Se 5 的反应得到伯硒代羧酸酰胺。这些化合物与 α-卤代酮的环化得到了多种功能化的 1,3-硒唑。使用 P 2 Se 5 还可以方便地合成硒代羧酸二酰胺,该二酰胺被转化为双(硒唑-2-基)烷烃(“双硒唑”)。开发了一种合成硒脲的实用方法。这种有用的小结构单元成功地应用于伯2-氨基-1,3-硒唑的合成。
2-Acyl-1,3-selenazoles were prepared in two steps from α-bromoketones and seleno amides. The base mediated fragmentation of these compounds afforded 2-unsubstituted 1,3-selenazoles. The reaction of 2-acyl-1,3-selenazoles with hydroxylamine hydrochloride afforded oximes which were transformed into 2-carbamoyl-1,3-selenazoles by a regioselective Beckmann rearrangement.
An efficient and rapid procedure for the synthesis of 2,4-disubstituted-1,3-thiazoles and selenazoles has been described by the reaction of α-bromoketones with thiourea, phenylthiourea and selenourea at ambient temperature in aqueousmediumunder ultrasonic irradiation. Analytically pure products were formed within 10–60 s in excellent yields. The advantageous features of this non-conventional methodology
Sodium fluoride as an efficient catalyst for the synthesis of 2,4-disubstituted-1,3-thiazoles and selenazoles at ambient temperature
作者:Janardhan Banothu、Krishnaiah Vaarla、Rajitha Bavantula、Peter A. Crooks
DOI:10.1016/j.cclet.2013.10.001
日期:2014.1
Abstract Sodium fluoride was found to be a simple, mild and efficient catalyst for the synthesis of 2,4-disubstituted 1,3-thiazoles and selenazoles utilizing phenacyl bromides/3-(2-bromoacetyl)-2 H -chromen-2-one and thiourea/phenylthiourea/selenourea in aqueous methanol at ambient temperature. Analytically pure products are formed within 1–3 min in excellent yields.