Domino Synthesis of 2-Substituted Benzothiazoles by Base-Promoted Intramolecular C–S Bond Formation
作者:Yogendra Kumar、Hiriyakkanavar Ila
DOI:10.1021/acs.orglett.9b02855
日期:2019.10.4
developed, involving base-promoted one-pot addition of active methylene compounds to o-iodoarylisothioacyanates and subsequent intramolecular C-S bond formation of the resulting thioamidate anion. The reaction proceeds at room temperature within 1-3 h, affording diversely substituted benzothiazoles in high yields. A possible radical intermediate pathway, via an SRN1 mechanism, has been proposed for intramolecular
three-component tandem reaction has been developed for the convenient and practical synthesis of 1,4-benzothiazines. A variety of terminal alkynes and 2-iodo/bromophenyl isothiocyanates underwent this one-potcyclization with aqueous ammonia to afford 1,4-benzothiazines in moderate to good yields.
2-haloaryl isothiocyanates and isocyanides to access benzo[d]imidazo[5,1-b]thiazoles has been realized efficiently under metal- and photocatalyst-free conditions. The reaction mechanism was explored by several preliminary experiments involvingreactive intermediate, free radical inhibitors, and corresponding photoelectric spectra. This protocol possesses some advantages over the previous methods such as
在无金属和无光催化剂的条件下,已经有效地实现了可见光促进的2-卤代芳基异硫氰酸酯和异氰酸酯的级联环化反应,以接近苯并[ d ]咪唑并[5,1- b ]噻唑。通过涉及反应性中间体,自由基抑制剂和相应的光电光谱的几个初步实验探索了反应机理。该方案相对于先前的方法具有一些优势,例如易于获得和廉价的底物,无金属催化剂,步骤和原子经济,反应条件温和。
A silver(<scp>i</scp>)-catalyzed cascade bicyclization strategy for synthesis of 5<i>H</i>-benzo[<i>d</i>]tetrazolo[5,1-<i>b</i>][1,3]thiazines
A simple and efficient protocol for silver(I)-catalyzed tandem reaction of o-alkynylphenyl isothiocyanates with sodium azide has been developed, affording a series of 5H-benzo[d]tetrazolo[5,1-b][1,3]thiazines in moderate to good yields. In this transformation, a [3 + 2] cycloaddition reaction mechanism was involved and two new rings were formed in one pot.
已经开发了一种简单有效的方案,用于银(I)催化邻炔基苯基异硫氰酸酯与叠氮化钠的串联反应,提供了一系列5 H-苯并[ d ]四唑[5,1- b ] [1,3]噻嗪产量中等至良好。在该转化中,涉及[3 + 2]环加成反应机理,并且在一个罐中形成了两个新的环。