Synthesis of 2‐Unsubstituted 1,3‐Selenazoles by Cyclization of Selenoformamide with <i>α</i>‐Bromocarbonyl Compounds

Below, Harald; Pfeiffer, W.‐D.; Geisler, Karlheinz; Saghyan, Ashot S.; Fischer, Christine; Langer, Peter

doi:10.1002/jhet.2076

Cited by 5 publications

(2 citation statements)

References 23 publications

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“…to the instability of the products. 24,25 The low yields of products 33a-h, in comparison for the yields obtained by the method described in Scheme 15 and Figure 4, can be explained by the unstable nature of selenoformamide (32) which undergoes decomposition during the reaction. In addition, 32 is difficult to prepare in pure form.…”

Section: Account Synlettmentioning

confidence: 97%

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Adventures in 1,3-Selenazole Chemistry

Langer

2021

Synlett

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The synthesis of 1,3-selenazoles and related compounds, including 2,4,5-trisubstituted, 2,4-disubstituted, 4,5-disubstituted, 4-substituted 1,3-selenazoles, and parent unsubstituted 1,3-selenazole, is highlighted. Emphasis is also given on 2-benzoyl-1,3-selenazoles which can be functionalized by Knoevenagel reactions or by rearrangements via their corresponding oximes. Syntheses of bis-, tris-, and tetrakis(1,3-selenazoles) are discussed as well. 1,3,4-6H-Selenadiazines are available from selenosemicarbazides and can undergo ring-contraction or deselenation reactions. Most syntheses rely on the application of selenocarboxylic amides, selenourea and related building blocks which are conveniently available by reaction of the corresponding oxygen analogues with P4Se10.1 Introduction2 Selenocarboxylic Amides3 2,4,5-Tri- and 2,4-Disubstituted 1,3-Selenazoles4 Bis(1,3-selenazoles)5 2-Amino-1,3-selenazoles6 2-Unsubstituted 1,3-Selenazoles7 1,3,4-Selenadiazines8 Conclusions

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Section: Account Synlettmentioning

confidence: 97%

“…The cyclization of selenoformamide (32) with bromoacetic aldehyde afforded completely unsubstituted 1,3selenazole (35), albeit in only 3% yield (Scheme 19). 24,25 The product, which was unknown at that time, proved to be unstable. All attempts to completely remove the solvent resulted in decomposition.…”

Section: Scheme 18 Synthesis Of 32 and 33a-hmentioning

confidence: 99%