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Enzymatic halogenation of pyrazoles and pyridine derivatives
Author(s) -
Franssen M. C. R.,
Van Boven H. G.,
Van Der Plas H. C.
Publication year - 1987
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570240516
Subject(s) - chemistry , halogenation , pyrazole , bromide , pyridine , yield (engineering) , medicinal chemistry , halide , hydrogen peroxide , chloride , substrate (aquarium) , potassium bromide , enzyme , organic chemistry , potassium , materials science , oceanography , metallurgy , geology
Pyrazole, 1‐methylpyrazole and 3‐methylpyrazole are chlorinated by the enzyme chloroperoxidase from Caldariomyces fumago , in the presence of potassium chloride and hydrogen peroxide at p H 2.7, yielding the corresponding 4‐chloro derivatives in good yields. A 4 H ‐pyrazole is proposed as an intermediate in this reaction. 2‐Aminopyridine was converted regiospecifically by the same enzyme into 2‐amino‐3‐chloropyridine, and 8‐hydroxyquinoline gave its 5,7‐dibromo‐derivative in very good yield when bromide ion was used as the halide substrate.