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Reaction of 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione (PTAD) with bicyclic monoterpenes
Author(s) -
Adam Waldemar,
De Lucchi Ottorino,
Hill Karlheinz
Publication year - 1982
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19821150527
Subject(s) - camphene , cycloaddition , bicyclic molecule , chemistry , cyclopropane , pinene , medicinal chemistry , steric effects , stereochemistry , organic chemistry , ring (chemistry) , catalysis , chromatography , essential oil
The cycloaddition of the bicyclic monoterpenes camphene ( 4 ), α‐pinene ( 5 ), β‐pinene ( 6 ), 2‐carene ( 7 ), bornene ( 8 ), and tricyclane 9 with PTAD was investigated. Only camphene and α‐pinene gave rearranged urazoles ( 11 , 14 ) via dipolar cycloaddition. Ene‐reaction was the predominant reaction course for α‐pinene (→ 15 ) and the exclusive route for β‐pinene (→ 16 ) and 2‐carene (→ 17 ). Steric hindrance by the gem ‐dimethyl group prevents cycloaddition of bornene. The cyclopropane rings in the tricyclane 9 and 2‐carene are not sufficiently strained to undergo [2π + 2σ]‐cycloaddition with PTAD. None of the monoterpenes gave [2π + 2σ]‐cycloaddition.