Methylamine → 2-Isopropyl-4-(N-methyl)amino-methyl thiazole

참여 물질

반응 단계

The thioisobutyramide resulting from Example 73A was dissolved in 70 mls THF and added slowly to a solution of (34.1 g, 0.27 mols) 1,3-dichloracetone in 40 mls THF. A 10 ml rinse of THF was used to completely transfer the thioamide. The reaction was carried out in a 250 ml flask with mechanical stirring under nitrogen atmosphere. The reaction temperature was maintained below 25° C. during addition with a 15°±5° C. bath. The bath was kept in place for 1 hour after which it was removed and the reaction stirred for 18 hours. Next this stirred chloromethyl-thiazole solution was added to 376 mls (4.37 mols) 40% aqueous methylamine solution at 15° C. in a 1 liter flask. The temperature was maintained below 25° C. during addition. After half an hour the bath was removed and the reaction stirred for 3 hours at ambient temperature. The solvent was removed under vacuum with a 50° C. bath to an end volume of 310 mls. The residue was then basified with 50 g 10% NaOH to pH 12 and extracted into methylene chloride (2×160 mls). The combined organics were then washed with 1×150 g of 20% ammonium chloride followed by 1×90 g of 20% ammonium chloride. The combined aqueous washes were then back extracted with 150 mls methylene chloride. The combined product methylene chloride layers were then extracted with 100 g of a solution of 25 g conc. HCl and 75 g water. This acidic product solution was then washed with 135 mls methylene chloride. Next the acidic product solution was cooled, then neutralized with 100 g 20% NaOH solution. The product was extracted from this mixture with methylene chloride (2×135 mls). The solvent was removed under vacuum to afford the desired product as an amber oil. (yield approx. 28 grams)

출처 및 근거