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

1,2-Oxazines have been gained increasing interest in organic synthesis as useful intermediates, and key building blocks in the synthesis of natural products, and unnatural cyclic amino acids. 1,2-Oxazines also play an important role as pharmacological entities exhibiting a broad spectrum of biological activities. However, there have been only a few reports on the reaction of cyclopenta[d][1,2]oxazine and its derivatives. Linn and Sharkey reported that the treatment of benzoylated cyclopentadiene with hydroxylamine afforded cyclopenta[d][1,2]oxazine with no substituents. Lloyd and co-workers reported the synthesis of cyclopenta[d][1,2]oxazine by reaction of diaroylcyclopentadienes with hydroxylamine. They had failed to get the corresponding aldehydes by treatment of cyclopenta[d][1,2]oxazines with ethyl orthoformate in the presence of boron trifluoride-ether complex. On the other hand, they could synthesize only 7-bromocyclopenta[d][1,2]oxazine with N-bromosuccinimide. Previously, we reported Suzuki reaction of 7-iodocyclopenta[d][1,2]oxazines to afford the corresponding 7-arylated cyclopenta[d][1,2]oxazines. Since Lloyd and co-workers reported reactions of cyclopenta[d][1,2]oxazine, there have been paid little attention to the chemistry of cyclopenta[d][1,2]oxazine and the application of cyclopenta[d][1,2]oxazines as a synthetically useful starting material presumably due to the limited chemical stability of cyclopenta[d][1,2]oxazine skeletons. Herein, we report a facile Friedel-Craft acylation of cyclopenta[d][1,2]-oxazines to afford the synthetically useful 7acyl derivatives. This is the first example of Friedel-Craft reaction of cyclopenta[d][1,2]-oxazine as given in Table 1. Various functional groups can be tolerated, such as phenyl esters, lactones, and acetyl groups, and yields of reaction were moderate to excellent. The substituent position of 7acylcyclopenta[d][1,2]oxazines could be unequivocally determined by the coupling constant of cyclopentadiene from spectral data. In reference, the coupling constant of

First Example of Friedel-Craft Acylation of Cyclopenta[d][1,2]oxazines and Further Reaction to Their Oxime and Hydrazone Derivatives