Ethylamine → Methyl 5-(3,5,5,8,8-Pentamethyl-5,6,7,8-tetrahydronaphthalen-2-ylsulphonyl)penta-2,4-diynoate

Participants

Reaction Steps

A 70% solution of ethylamine in water (563 μl) is added dropwise to a mixture of methyl 3-bromopropynoate (632 mg, 2.88 mmol), hydroxylamine hydrochloride (162 mg, 2.33 mmol) and copper (I) chloride (10 mg) in methanol. A solution of 6-ethynylsulphonyl-1,1,4,4,7-pentamethyl-1,2,3,4-tetrahydronaphthalene (Example 7(b)) (500 mg, 1.94 mmol) in methanol (5 ml) is then added dropwise. The reaction medium is stirred for 15 h at room temperature and treated with saturated aqueous ammonium chloride solution and ethyl acetate. The organic phase is washed with water, dried over magnesium sulphate and concentrated. The product is obtained in the form of an oil after purification by flash chromatography on silica (80/20 heptane/CH2Cl2). 1H NMR/CDCl3: 1.26 to 1.28 (s, 12H); 1.67 (s, 4H); 2.35 (s, 3H); 3.78 (s, 3H); 7.14 (s, 1H); 7.48 (s, 1H); 13C NMR/CDCl3: 19.7; CH3/31.8; 4*CH3/34.1; Cq/34.3; Cq/34.9; 2*CH2/52.9; CH3/71.7; CH/72.1; CH/80.2; Cq/124.5; Cq/127.6; Cq/12.8.3; CH/129.3; CH/134.8; Cq/144.6; Cq/146.2; Cq/153.4; Cq.

Provenance & Evidence