Sodium Hydroxide → 2-(4-n-Butylamino-2,2,6,6-tetramethylpiperidin-1-yl) ethanol

) A solution of 12.6 g (42.2 mmol) of N-n-butyl-N-[ 1-(2-hydroxyethyl)-2,2,6,6-tetramethylpiperidin-4-yl]acetamide [Example 1bη2] in 180 ml of 2N hydrochloric acid is refluxed for 48 hours. The reaction mixture is then cooled 0°-5 C. and, after addition of 40 ml of 30% sodium hydroxide solution, extracted twice with toluene. The organic phases are washed with water, combined, dried over sodium sulfate, and concentrated on a vacuum rotary evaporator. Chromatography of the residue on silica gel with the solvent system ethyl acetate/ethanol/triethylamine=50:2:1 yields 8.1 g (68%) of 2-(4-n-butylamino-2,2,6,6-tetramethylpiperidin-1-yl) ethanol (208) as a white powder of m.p. 106°-111° C. Analysis: calcd: C 70.26%; H 12.58%; N 10.92%. found: C 70.42%; H 12.85%; N 11.00%. ##STR65## τ) 833 g (5.30 mol) of 4-hydroxy-2,2,6,6-tetramethylpiperidine and 418 g (1.05 mol) of 2-butyne-1,4-diol-ditosylate [C.A. Registry No. 6337-59-3] in 3.6 1 of acetonitrile are placed, under argon, in a round-bottomed flask equipped with magnetic stirrer and condenser. The reaction mixture is refluxed overnight, then cooled, poured on ice and extracted repeatedly with ethyl acetate. The organic phases are combined, dried over sodium sulfate and concentrated on a vacuum rotary evaporator. Crystallisation of the residue from ethanol yields 295 g (76%) of 1,4-bis(4-hydroxy-2,2,6,6-tetramethylpiperidin-1-yl)-but-2-yne (209), m.p. 203.4° C., in the form of white crystals. Analysis: calcd: C 72.48%; H 11.06%; N 7.68%. found: C 72.52%; H 11.12%; N 7.75%. ##STR66## κ) The HALS diol (210) is known and described in U.S. Pat. No. 4,569,997 (Ciba-Geigy, Example 1, column 14). ##STR67## λ)1.) 9.15 g (50 mmol) of adipyl dichloride are added dropwise at 0°-5° C., under nitrogen, to a stirred solution of 22.2 g (105 mmol) of 4-n-butylamino-2,2,6,6-tetramethylpiperidine IEP-A-302 020, Example 1, page 41 in 70 ml of triethylamine and 150 ml of toluene. After c. 30 minutes the reaction mixture is heated to c. 100° C. and stirred for 90 minutes at this temperature. The resultant dense suspension is thereafter cooled to room temperature, filtered to remove the salts, and the filtrate is concentrated on a vacuum rotary evaporator. Chromatography of the residue on silica gel with the solvent system ethyl acetate/ethanol/triethylamine=20:1:1 and crystallisation of the pure fractions from hexane yields 17.15 g (64%) of N,N'-di-n-butyl-N,N'-bis-(2,2,6,6-tetramethyl-4-piperidinyl)hexane diamide as a white powder; m.p. 134°-144° C.