A THF solution of 1-(4-formylbenzoyl)-4-isopropylpiperazine (containing 945 g of 1-(4-formylbenzoyl)-4-isopropylpiperazine and 3879 g of THF) was charged to a reaction vessel followed by the addition of morpholine (576.3 g, 6.55 mol). After 20 min, the reaction was cooled to about 0-10° C. and sodium triacetoxyborohydride (1167.3 g, 5.23 mol) was added in portions. Upon reaction completion, 10% sodium hydroxide solution (3623.2 mL, 9.06 mol) was added slowly and the reaction mixture was stirred for 20 min. The layers were separated, and the aqueous layer was washed with THF. The combined organic layers were dried over magnesium sulfate. The dried THF solution of (4-Isopropyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone was used without further manipulations.
