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Reactivity of methyl (3,6‐dichloropyridazin‐4‐yl)acetate towards nucleophiles
Author(s) -
Adembri G.,
De Sio F.,
Nesi R.,
Scotton M.
Publication year - 1976
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.5570130601
Subject(s) - chemistry , chlorine , medicinal chemistry , reactivity (psychology) , pyridazine , nucleophile , hydrazide , acetic acid , hydrazine (antidepressant) , hydrochloric acid , ring (chemistry) , chlorine atom , acetic anhydride , organic chemistry , catalysis , medicine , alternative medicine , pathology , chromatography
Abstract Methyl (3,6‐dichloropyridazin‐4‐yl)acetate (II), prepared from methyl (3,6‐dihydroxypyrid‐azin‐4‐yl)aeetate (1) by chlurination with phosphorus oxychloride, was used for studies of nucleo‐philic displacement reactions and it has been found that only the chlorine atom at position 6 was displaced with hydrazine. With diluted hydrochloric acid both chlorine atoms were displaced with the 6‐oxo isomer predominating. By turning the aromatic ring of pyridazine into an o ‐quinoid system, the chlorine atom at position 3 became mobile. Cyelization of (6‐hydrazino‐s‐triazolo‐[4,3‐b ]pyridazin‐7‐yl)acetic acid hydrazide (XIX) gave 6‐aminopyrrolo[3,2‐ e ] s ‐triazlo[ 4,3‐ b ]‐pyridazm‐7(8 H )one (XXI).