ChemInform Abstract The exciton couplings between a benzoate chromophore and planar 1,3-diene as well as α,β-unsaturated carbonyl chromophore for determination of the absolute configuration of the axially dissymmetric benzoates (I)-(VI) are investigated. The effect of E/Z configuration of the chromophore on exciton interaction is noted.
When attempts were made to purify the ester 32 on a silica column a low yield of it was eluted. It was followed by the more polar hydrolysis product, the oxime 33 (see below). When a basic alumina column was used cleavage to 33 was complete, no 32 being eluted.The oxime 33 from the column (0.033 g, 0.29 mmol) was dissolved in CDC13 (0.5 mL) in an NMR tube, and pyridine (0.24 mL, 0.29 mmol) and benzoyl chloride (0.041 g, 0.29 mmol) were added. The 1H spectrum, run within 30 s, showed the reaction to be already complete. The solution was worked up with ether
I. Experimental and Characteristic data S2-S9 II. 1 H and 13 C NMR Spectra S10-S15 S2 EXPIRIMENTAL SECTION GENERAL All reactions were carried out under nitrogen atmosphere. Glassware was dried in an oven prior to use. Reactions were monitored by TLC with Merck silica gel 60 F 254 plates or with neutral aluminiumoxide 60 F 254 plates. Flash column chromatography was performed on silica gel 60 (70-230 mesh ASTM) from Merck. All other chemicals like diphenyl phosphoryl azide (DPPA), 2-chloro-5-fluoroanisole N-chlorosuccinamde (NCS), 4-fluoro-2, 3-dihydroinden-1-one, ptolylsulfonylmethyl isocyanide (TOSMIC) and aryl isocyanates and thiocyanates were brought from Aldrich, Acros or Merck companies. Melting points were determined in open capillary tubes on a Mel-temp apparatus and were uncorrected. Microanalyses were performed on a Yanaca CHN Corder MT-3 elemental analyzer. IR spectra were recorded on a Perkin-Elmer FT-IR 240-c spectrophotometer using KBr optics. 1 H and 13 C NMR spectra were recorded on AMX 400 MHz NMR spectrometer from Bruker in DMSO-d 6 unless otherwise stated. The human neuroblastoma cells (SK N SH) and human colon carcinoma cells (Colo 205) were received from National Center for Cell Sciences, Pune, India. SK N SH cells were grown in minimal essential media (Gibco) with 0.1mM non-essential amino acids and 1.0 mM sodium pyruvate with 10%FBS and Colo 205 cell lines were grown on RPMI 1640 supplemented with 10% fetal
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