15547-41-8Relevant academic research and scientific papers
Chiral DNA gyrase inhibitors. 3. Probing the chiral preference of the active site of DNA gyrase. Synthesis of 10-fluoro-6-methyl-6,7-dihydro-9- piperazinyl-2H-benzo[a]quinolizin-20-one-3-carboxylic acid analogues
Fecik, Robert A.,Devasthale, Pratik,Pillai, Segaran,Keschavarz-Shokri, Ali,Shen, Linus,Mitscher, Lester A.
, p. 1229 - 1236 (2007/10/03)
In pursuit of an apparent literature anomaly, S- and R-6-methyl-6,7- dihydro-2H-benzo[a]-quinolizin-2-one-3-carboxylic acids (12 and 22) were synthesized by an unambiguous route from optically active norephedrines, and their antibacterial potencies were measured. Against Gram-negative microorganisms and DNA gyrase a preference for S-absolute configuration was found whereas R-absolute stereochemistry was more active against Gram-positives. These results are in partial conflict with an earlier report. In an attempt to enhance potency, racemic 10-fluoro-9-piperazinyl (35) and related analogues were synthesized by a novel route. The latter analogues were surprisingly unimproved in potency. The implications of these findings are briefly discussed.
Tetrahydroisoquinolines. Part 4. Enantioselective Conversion of (+)-Amphetamine into (+)-(1R,3S,4S)-and (-)-(1S,3S,4R)-1,2,3,4-tetramethyl-1,2,3,4-tetrahydroisoquinoline via Tricarbonyl(arene)chromium Methodology
Coote, Steven J.,Davies, Stephen G.,Sutton, Kevin H.
, p. 1481 - 1488 (2007/10/02)
Co-ordination of the tricarbonylchromium moiety to the diastereotopic faces of (+)-(3S)-2,3-dimethyl-1,2,3,4-tetrahydroisoquinoline (9) occurs preferentially to the least hindered face.The mixture of tricarbonyl chromium (11) and tricarbonyl-chromium (12) thus generated may undergo regio- and stereo-selective exo-1,4-dimethylation by sequential treatment with BuLi-MeI and tBuLi-MeI to give (+)->tricarbonyl-(1R,3S,4R)-1,2,3,4-tetramethyl-1,2,3,4-tetrahydroisoquinoline>chromium (15) and (+)-chromium (16).The relative and absolute stereochemistry of (15) is assigned on the basis of differential n.O.e. experiments and confirmed by single crystal X-ray structure determination.Oxidative decomplexation gives (1R,3S,4S)-and (1S,3S,4R)-(-)-1,2,3,4-tetramethyl-1,2,3,4-tetrahydroisoquinolines (17) and (18).
