Methylamine → 6-Ethoxy-2-benzothiazolesulfenamide

Participants

Reaction Conditions

Reaction Steps

A solution of 40% aqueous methylamine (80 ml) was placed in a 250 ml 3-necked flask, equipped with a powerful stirrer and two-addition funnels. The solution was cooled to -10° C. with an ice/methanol bath. A solution of 6-ethoxy-2-mercaptobenzothiazole (2.0 g., 0.0095 mol) in 20 ml of 5% NaOH was prepared, cooled to 10° C. and placed into one of the addition flasks. The second addition flask was charged with 40 ml of 5.25% NaOC1 which was cooled to 5° C. The two solutions were added simultaneously to the aqueous methylamine over a period of one hour with the rate of addition of the 6-ethoxy-2-mercaptobenzothiazole solution slightly faster than the addition of the NaOC1 solution The temperature of the reaction was maintained at --5° C.-0° C. The reaction was stirred for 15 minutes upon completing the addition and vacuum filtered to yield 6-ethoxy-2-benzothiazolesulfenamide. The 6-ethoxy-2-benzothiazolesulfenamide was immediately dissolved in 100 ml of acetone and oxidized with 50 ml of 5% KMnO4. The temperature of the oxidation was kept below 30° C. The MnO2 was removed by vacuum filtration and the filter cake washed with 25 ml of 5% NaOH. The 6-ethoxy-N-methyl-2-benzothiazolesulfonamide was precipitated from the solution by acidification with 5% HC1 to yield 1.3g. (yield 50.3%). The product was purified by dissolving it in 10% Na2CO3 and precipitating it with 5% Hl. m.p. 129° C.-131° C.; NMR(DMSO- d6) 8.4(s, lH), 8.3-7.1cm, 3H) 4-1 4-3.9(q,1 2H) 2.7(s, 3H 1.5-1.2(t, 3H. IR(KBr) 3100 cm (N-H) 1345 cm-1, 1155 cm (S=O). Elemental Analyses: C10H12N2O3S2 ; Calculated: C 44.09% H 4.44% N 10.28%. Found: C 44.04% H 4.51% N 10.18%.

Provenance & Evidence