反应详情

A solution of the dimethyl chromogen (20) prepared according to Example 2 (38 mg; 0.16 mmol) in anhydrous tetrahydrofuran (3.2 mL) was stirred at ambient temperature and treated portionwise, over 1.5 hours, with N-tosyl-L-alaninyl chloride (35) from step (a) of the present example (243 mg; 0.93 mmol) and anhydrous pyridine (280 μL) while maintaining an inert gas atmosphere over the reaction. Once the addition was complete, the reaction was stirred for an additional hour then blended into ethyl acetate (50 mL) and then extracted twice with aqueous 1 N citric acid (10 mL @). The combined aqueous extracts were washed once with ethyl acetate (10 mL) and the combined ethyl acetate layers were extracted thrice with 5% aqueous NaHCO3 (10 mL each). The combined NaHCO3 extracts were washed once with ethyl acetate (10 mL) then the combined ethyl acetate layers were washed once with brine (20 mL), dried over Na2SO4, filtered and evaporated to dryness in vacuo to give an orange viscous oil (110 mg). This was chromatographed on silica gel (50 g) using acetone/CHCl3 (9) solvent. The yellow major product band (Rf =0.32) was collected and evaporated to dryness in vacuo to obtain 7-(N-tosyl-L-alaninyloxy)-9,9-dimethyl-9H-acridin-2-one (36) (40 mg; 54%) in the form of a yellow glass.

1. temperaturewhile maintaining an inert gas atmosphere
2. customover the reaction
3. additionOnce the addition
4. stirringthe reaction was stirred for an additional hour
5. extractionextracted twice with aqueous 1 N citric acid (10 mL @)
6. washThe combined aqueous extracts were washed once with ethyl acetate (10 mL)
7. extractionthe combined ethyl acetate layers were extracted thrice with 5% aqueous NaHCO3 (10 mL each)
8. washThe combined NaHCO3 extracts were washed once with ethyl acetate (10 mL)
9. washthe combined ethyl acetate layers were washed once with brine (20 mL)
10. dry with materialdried over Na2SO4
11. filtrationfiltered
12. customevaporated to dryness in vacuo