Premium
Trapping of a Thiocarbonyl Ylide with Imidazolethiones, Pyrimidinethione, and Thioamides
Author(s) -
Mlostoń Grzegorz,
Gendek Tomasz,
Linden Anthony,
Heimgartner Heinz
Publication year - 1999
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/(sici)1522-2675(19990210)82:2<290::aid-hlca290>3.0.co;2-p
Subject(s) - chemistry , ylide , thiirane , intramolecular force , adduct , yield (engineering) , medicinal chemistry , bicyclic molecule , reagent , protonation , pyrimidine , nucleophilic substitution , stereochemistry , organic chemistry , ring (chemistry) , ion , materials science , metallurgy
The reactions of 1,1,3,3‐tetramethyl‐8‐thia‐5,6‐diazaspirol[3.4]oct‐5‐en‐2‐one ( 1a ) with imidazole‐2‐thiones 3 and pyrimidine‐2(1 H )‐thione ( 6 ) in CHCl 3 at 40 – 50° yield 2,2,4,4‐tetramethylcyclobutanone dithioacetals of type 4 and 7 , respectively, by interception of the intermediate thiocarbonyl ylide 2a ( Scheme 2 ). Thiirane 5 is formed as a minor product by 1,3‐dipolar electrocyclization of 2a . When thioacetamide ( 8a ) and thiobenzamide ( 8b ) are used as trapping reagents, the primary adduct 10 undergoes a spontaneous cyclization by intramolecular nucleophilic addition of the imino group at the carbonyl group to yield bicyclic products of type 9 . The structure of 9a has been established by X‐ray crystallography.