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Halogenation of Xanthenyl and Thioxanthenylallenes
Author(s) -
AbdulMalik Nadia Fouad,
Awad Sami Bassili,
Sakla Afly Badie
Publication year - 1979
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19790620616
Subject(s) - chemistry , xanthene , sulfuryl chloride , halogenation , bromine , reagent , chloride , ion , medicinal chemistry , organic chemistry , combinatorial chemistry
Reactions of acids with vinylidenexanthenes (or thioxanthenes) 1 and 9‐methoxy‐9‐vinylxanthenes (or thioxanthenes) 8 give xanthene‐ (or thioxanthene‐) 9‐spiro‐1′‐indenes 7 . With bromine or sulfuryl chloride they give the corresponding 2′‐halogenoxanthene‐ (or thioxanthene‐)9‐spiro‐1′‐indenes 5 . Formation of such derivatives depends on preferential attack of the reagents on allenes 1 to give initially xanthylium (or thioxanthylium) ions 3 which cyclize. One π bond of the allenes 1 can be selectively reduced in acid media. Chemical and spectral evidence for these routes are presented.