[CH:1]1[C:11]2[CH2:10][S:9][C:8]3[CH:12]=[CH:13][CH:14]=[CH:15][C:7]=3[S:6][C:5]=2[CH:4]=[CH:3][CH:2]=1.C([Li])CCC.O.[CH3:22][N:23]([CH3:27])[CH2:24][CH2:25]Cl>CCOCC.CCCCCC>[CH3:22][N:23]([CH3:27])[CH2:24][CH2:25][CH:10]1[S:9][C:8]2[CH:12]=[CH:13][CH:14]=[CH:15][C:7]=2[S:6][C:5]2[CH:4]=[CH:3][CH:2]=[CH:1][C:11]1=2A solution of 3.40 g of 11H-dibenzo(b,e)-1,4-dithiepin (K. Sindelar, M. Protiva and M. Hrubantova, Czech. 202.239) in 50 ml of ether was treated dropwise over 20 minutes of 15% n-butyllithium solution in hexane in a nitrogen atmosphere. The mixture was stirred for 30 minutes at room temperature and then treated with external cooling with ice and water and with 10 ml of 2-dimethylaminoethyl chloride, added dropwise. Then, the mixture was stirred for another 2 hours at room temperature. It was then washed with water and the basic product extracted into a mild excess of 1:1 dilute hydrochloric acid. The acid aqueous layer was separated, made alkaline with aqueous ammonia and the base extracted with ether. The extract was dried with potassium carbonate and evaporated. The remaining oily base was dissolved in 7 ml of acetone and treated with a solution of 1.81 g of oxalic acid in 5 ml of acetone. The crystalline hydrogen oxalate (5.31 g) separated, was filtered with suction and purified by recrystallization from aqueous ethanol, m.p. 195°-197° C.
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