Hydrochloric Acid → 5-Ethyl-7-hydroxy-8-methoxy-benzo[c]phenanthridinium hydrogen sulfate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

183 mg (0.5 mmol) of 7-benzyloxy-8-methoxybenzo[c]phenanthridine (compound D-7) were admixed with 0.13 ml (1.0 mmol) of ethyl trifluoromethanesulfonate and 0.9 ml of dry toluene, and the resulting mixture was heated to 100° C. for 5 hours. After that, the mixture was admixed with 4 ml of acetic acid and 1 ml of concentrated hydrochloric acid, and heated to 100° C. for 1 hour. Thereafter, the reaction mixture was gradually added to ice water. The reaction mixture thus diluted was neutralized by portionwise adding thereto sodium hydrogen carbonate, and then extracted with chloroform. The chloroform extract layer was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The resultant residue was refined by a silica gel chromatography, wherein use was made, as eluant, of a chloroform-methanol mixture (9:1). The main fractions were collected and concentrated to obtain a dark violet solid material, which was compound E-7 having a structure represented by the general formula E. Next, compound E-7 was dissolved in a small amount of methanol, and the solution thus obtained was acidified by portionwise adding thereto a dilute aqueous solution of sulfuric acid in an amount of from 1.0 to 2.0 mol per 1 mol of the compound, so that the color of the solution of the compound was changed into yellow or orange. The aqueous solution of the compound was then concentrated under reduced pressure. Acetone was added portionwise to the concentrated solution under shaking to form a precipitate, which was separated by filtration, and dried, so that the aimed compound A-7, wherein X- =HSO4-, was obtained as yellow powder in an amount of 160 mg (yield: 79.7%).

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