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Synthesis of 7α‐chloro‐16α‐methylprednisolone 17α,21‐dipropionate‐4‐ 14 c (alclometasone dipropionate‐4‐ 14 c)
Author(s) -
Terasawa Tadao,
Atsumi Kazunori,
Yokoshima Tetsuyoshi,
Ohyabu Shintaro,
Fukasaku Noboru
Publication year - 1986
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2580230913
Subject(s) - chemistry , chloranil , hydrochloric acid , trimethylsilane , medicinal chemistry , dehydrogenation , lithium (medication) , organic chemistry , hydrogen chloride , adduct , hydrogen iodide , iodine , medicine , endocrinology , catalysis
Grignard reaction of the enol‐lactone 8 with 14 C‐methylmagnesium iodide afforded an adduct 9 which on subsequent treatment with lithium 2,6‐di‐t‐butylphenoxide gave the enone 10 . Conversion of 10 to the trienone 12 was performed by two‐step dehydrogenation using chloranil and then DDQ. The protecting groups were removed on treatment whith 2N‐hydrochloric acid‐trifluoroacetic acid to give the triol 13 . The 17α,21‐bisesterification of 13 was carried out according to the orthoester procedure. Finally, addition of dry hydrogen chloride to the resulting diester 16 led to the title compound 17 .