2,5-Dimethylpiperazine, trans- → trans-4-(alpha-(2,5-Dimethyl-1-piperazinyl)-3-(tert-butyldimethylsilyloxy)benzyl)-n,n-dimethylbenzenesulfonamide

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Reaction Conditions

Reaction Steps

The alcohol (88.8 g, 0.21 mol) was treated with thionyl chloride in dichloromethane as described in Example 1 to give 93.7 g of 4-(3-(tert-butyldimethylsilyloxy)-α-chlorobenzyl)-N,N-dimethylbenzenesulfonamide as a brown oil. The crude benzhydryl chloride (93.7 g, 0.21 mol) was combined with trans-2,5-dimethylpiperazine (71.8 g, 0.63 mol) in 400 mL of dimethylformamide and heated to 140° C. for 1 hour. The mixture was cooled to room temperature, poured into ice water and extracted with diethyl ether. The ether extracts were washed with 1M sodium hydroxide, water, and saturated aqueous sodium chloride, and dried over sodium sulfate. The solvent was removed and the residue was purified by chromatography on silica gel with dichloromethane:methanol to give 28.9 g (27%) of trans-4-(α-(2,5-dimethyl-1-piperazinyl)-3-(tert-butyldimethylsilyloxy)benzyl)-N,N-dimethylbenzenesulfonamide as a brown oil.

Provenance & Evidence