at 60 °C gave primarily the dehydration product 10 (oxalate mp 268-269 °C, NMR (Me2SO-d6) 6.32 [d, J = 28 Hz]), again demonstrating the sensitivity of this system. Therefore, the basification-extraction scheme described below was adopted.
Experimental SectionA mixture of 5.0 g (17.3 mmol) of atropine (7), 12 mL (87 mmol) of Cl3CCH2OCOCl, 17.28 g (173 mmol) of KHCO3, and 250 mL of CHC13 was refluxed for 4 h. The cooled mixture was filtered, the solvent removed on a rotary evaporator, and the residue freed from excess Cl3CCH2OCOCl (kugelrohr setup, oil pump, 80 °C). The remaining mixture of carbamates was stirred with 10 g of activated Zn dust16 in 100 mL of AcOH at 15 °C for 16 h. Inorganic matter was filtered off and the filter cake was washed with AcOH (50 mL). The filtrate was diluted with 150 mL of H20 and cooled in an ice bath. Aqueous NH3 (58%) was added dropwise (T < 10 °C) with stirring to pH ~6, at which point the mixture was extracted with ether to remove a small amount of neutral material. Addition of NH3 to the aqueous phase was continued to pH ~10. Extraction with four 150-mL portions of CHCI3, washing the combined extracts with brine, drying over anhydrous K2C03, and evaporating afforded 4.3 g (90.5%) noratropine(1) as colorless crystals, mp 114 °C (lit. mp 114 °C),n homogeneous on TLC (silica gel, 50 CH2Cl2/50 MeOH/1 Et3N).
[5,6-3H]arachidonic acid has been prepared by catalytic reduction of eicosa-cis-8,11,14-trien-5-ynoic acid (IV) over Lindlar catalyst. When either [5,6-3H]arachidonic acid or [5,6-3H]PGH2 is converted into PGI2 by swine aortic microsomes, the tritium at C-6 is lost to the medium. Thus, the progress of this enzymic rearrangement may be monitored by following the rate of tritium release. As swine aortic microsomes contain only low levels of cyclooxygenase, it is necessary to fortify the system with ram seminal vesicular microsomes (rich in cyclooxygenase) when [5,6-3H]arachidonic acid is used as the indirect substrate.
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