efficient asymmetrictotalsynthesis of (20S)-camptothecin has been accomplished in an overall yield of 12% starting from the commercially available 2-methoxynicotinic acid. The key step in the sequence is the Sharpless asymmetricdihydroxylation of a 4-(but-1-en-2-yl)pyridine derivative to establish the stereocenter of (20S)-camptothecin. totalsynthesis - stereoselectivity - asymmetric catalysis
Synthetic Route for New (Z)-5-[4-(2-Chloroquinolin-3-yl) Methoxy]benzylidinethiazolidine-2,4-diones
作者:Dhanaji V. Jawale、Umesh R. Pratap、Ramrao A. Mane
DOI:10.5012/bkcs.2011.32.7.2171
日期:2011.7.20
Synthetic route has been developed for the synthesis of new (Z)-5-[4-(2-chloroquinolin-3-yl) methoxy]benzyl-idinethiazolidine-2,4-diones (6a-h) starting from 2-chloro-3-hydroxymethyl quinolines (2a-h). The hydroxy methyl quinolines on tosylation yielded (3a-h). Condensation of the tosyl intermediates with 4-hydroxy benzaldehydes has been carried in DMF in presence of $K_2CO_3$ and obtained 4-quinolinyl methoxy benzaldehydes (4a-h). Conveniently Knoevenagel condensation of quinolinyl methoxy benzaldehydes (4a-h) and 2, 4-thiazolidinedione (5) has been carried in PEG-400 in presence of L-proline and obtained better yields of the titled compounds (6a-h).
Synthesis of New dihydropyrimidinones catalysed by dicationic ionic liquid
作者:DHANAJI V JAWALE、UMESH R PRATAP、APARNA A MULAY、JYOTIRLING R MALI、RAMRAO A MANE
DOI:10.1007/s12039-011-0127-y
日期:2011.9
A convenient multi step synthetic protocol for new dihydropyrimidinones bearing quinolynyl methoxy phenyl moiety has been developed from 2-chloro-3-formyl quinolines. The last step is one-pot Biginelli reaction of multicomponents, 4-((2-chloroquinolin-3-yl) methoxy) benzaldehydes, ethyl acetoacetate and urea mediated and catalysed by dicationic ionic liquid (3-methyl-1-[3-(methyl-1H-imidazolium-1-yl) propyl]-1H-imidazolium dibromide (C3 [min]2 2 [Br − ] )). Simple work-up procedures and moderate to good yields of the pyrimidinones and the intermediates are the merits of the route.