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Ring closures from enecarbamoyl thiocyanates. Syntheses of 5,6,7,8‐tetrahydro‐4‐thio‐2,4(l H ,3 H )‐quinazolinediones and related compounds
Author(s) -
Chupp John P.
Publication year - 1971
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.5570080407
Subject(s) - chemistry , thio , raney nickel , quinazolinone , medicinal chemistry , thiocyanate , ring (chemistry) , pyridine , isothiocyanate , alkylation , ammonium thiocyanate , phenyl isothiocyanate , stereochemistry , organic chemistry , catalysis
Alkyl (1‐cyclohexen‐1‐yl)carbamoyl chlorides ( 1 ) react with thiocyanate ion to form enecarbamoyl thiocyanates ( 2 ). In pyridine solution 2 readily isomerizes to the isothiocyanate 4 , which however is not isolated, but immediately transformed in good yields to tetrahydro‐4‐thio‐2,4(l H ,3 H )quinazolinediones ( 3 ). Various transformations of 3 , including conversion to tetra‐hydro‐2,4(2 H ,4 H )quinazolinedione ( 5 ), dithione ( 6 ), alkylation products ( 8 and 9 ), sodium salts 11 and Raney nickel degradation to 4,4a,5,6,7,8,8a‐octahydro‐l‐methyl‐2(1 H )quinazolinone ( 7 ), were carried out to investigate their chemistry and substantiate structural assignments.