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Pseudoesters and derivatives. XXV . 1,3‐Dipolar cycloaddition of diazomethane to 5‐methoxy‐3‐pyrrolin‐2‐ones
Author(s) -
Fariña Francisco,
Martín M. Victoria,
Paredes M. Carmen,
Tito Amelia
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.5570240507
Subject(s) - diazomethane , chemistry , dehydrohalogenation , structural isomer , cycloaddition , adduct , stereochemistry , methylation , 1,3 dipolar cycloaddition , organic chemistry , medicinal chemistry , catalysis , biochemistry , gene
Cycloaddition of diazomethane to pyrrolinones 1a,b,d,e affords only one regioisomer as a mixture of the epimeric pyrrolopyrazolines 2 and 2 ′,4‐Halo derivatives 1f,g react with diazomethane to give the two possible regioisomers 2 and 3. The regio‐ and stereochemistry of the adducts is evidenced by the 1 H‐nmr data. The primary adducts originated from the halopyrrolinones suffer dehydrohalogenation to give aromatized products, which by further methylation give derivatives of type 7, 8, 10 and 11.