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Intramolecular capture of pummerer rearrangement intermediates. I. Synthesis of pyrrolo[2,1‐c][1,4]benzothiazines
Author(s) -
Bates Dallas K.,
Winters R. Thomas,
Sell Burnell A.
Publication year - 1986
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.5570230311
Subject(s) - chemistry , sulfoxide , trifluoroacetic acid , pyrrole , pummerer rearrangement , alkylation , intramolecular force , substituent , medicinal chemistry , acetic acid , sulfide , yield (engineering) , toluene , alkyl , organic chemistry , catalysis , acetic anhydride , materials science , metallurgy
Treatment of 1‐(2‐alkylsulfinylphenyl)pyrroles with trifluoroacetic acid in refluxing toluene gives 4‐substituted pyrrolo[2,1‐ c ][1,4]benzothiazines in good yield when the alkyl group bears an electron withdrawing substituent on the α‐carbon. In the absence of such a group, starting material is recovered. The sulfoxides are prepared by oxidation (mCBPA) of the corresponding sulfide. The sulfides are prepared from 2‐aminobenzenethiol either by S ‐alkylation followed by conversion to the pyrrole using 1,4‐dimethoxytetrahydrofuran in glacial acetic acid or by S‐alkylation of 1‐(2‐phenylmercapto)pyrrole followed by oxidation to the sulfoxide.