English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The triethylamine mediated 1,3-dipolar cycloaddition reaction of 2-phenacyl- or 2-alkoxycarbonylmethylbenzothiazolium bromides with 3-nitrochromenes in ethanol at room temperature afforded functionalized tetrahydrobenzo[d]chromeno[3′,4′:3,4]pyrrolo[2,1-b]thiazoles in 83–95% yields and with high diastereoselectivity. The corresponding dehydrogenated benzo[d]chromeno[3′,4′:3,4]pyrrolo[2,1-b]thiazoles were also easily obtained by sequential oxidation with DDQ. The stereochemistry of the polycyclic compounds was clearly elucidated by analysis of NMR spectroscopy results and determination of single crystal X-ray structures. The reaction is believed to proceed via endo-[3 + 2] cycloaddition of the in situ generated anti-form ylides to the cyclic dipolarophiles.

rsc advances

Diastereoselective synthesis of benzo[d]chromeno[3′,4′:3,4]pyrrolo[2,1-b]thiazoles via cycloaddition reaction of benzothiazolium salts with 3-nitrochromenes