New methyl dehydroabietate derivatives: Synthesis and structural characterization

Citation
Ajd. Silvestre et al., New methyl dehydroabietate derivatives: Synthesis and structural characterization, MONATS CHEM, 129(11), 1998, pp. 1183-1197
Citations number
49
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry
Journal title
MONATSHEFTE FUR CHEMIE
ISSN journal
0026-9247 → ACNP
Volume
129
Issue
11
Year of publication
1998
Pages
1183 - 1197
Database
ISI
SICI code
0026-9247(199811)129:11<1183:NMDDSA>2.0.ZU;2-8
Abstract
The synthesis of some new chalcone and pyrazole type derivatives of methyl dehydroabietate is described. All compounds were exhaustively characterized using NMR and MS techniques. In order to confirm the information obtained by those techniques, the X-ray single crystal structures of methyl 12-acety ldehydroabietate and methyl 12-(4-methoxycinnamoyl)-dehydroabietate were de termined. Molecular mechanics calculations were performed in order to evalu ate the steric influence of the bulk of the C-12 substituent on the conform ational preference of the isopropyl group in these derivatives. The energy barriers of 52-3 and 53.6 kJ/mol found for the two compounds indicated that the C-12 substituent hinders the free rotation of the isopropyl group in b oth cases.