TABLE 2. 1H NMR Spectra of Synthesized Compounds
Com-
pound
Chemical shift, δ, ppm (spin-spin coupling constant J, Hz)
2a
2b
5a
5b
2.80 (2Н, t, J = 6.3, Н-2); 3.52 (2Н, t, J = 6.3, Н-3); 5.37 (2Н, s, NCH2С6Н5);
7.18-7.32 (7Н, m, C6H5 + H-5,6 benzimidazole); 7.46 (1Н, m, Н-7 benzimidazole);
7.59 (1Н, m, Н-4 benzimidazole); 12.47 (1Н, br. s, СООН)
2.35 (2Н, t, J = 6.1, Н-2); 3.50 (2Н, t, J = 6.1, Н-3); 5.87 (2Н, s, NCH2СО);
7.16 (2Н, m, H-5,6 benzimidazole); 7.43 (1Н, m, Н-7 benzimidazole); 7.62-7.75 (4Н, m,
Н arom. + Н-4 benzimidazole); 8.15 (2Н, d, J = 8.6, Н arom.); 12.12 (1Н, br. s, СООН)
2.86 (2Н, t, J = 6.4, CH2–CO); 3.45 (2Н, t, J = 6.4, S–CH2); 6.98 (1Н, СОNH);
7.12 (2Н, m, H-5,6 benzimidazole); 7.38 (1Н, s, СОNH);
7.53 (2Н, m, Н-4,7 benzimidazole); 12.58 (1Н, s, NH benzimidazole)
2.58 (2Н, t, J = 6.3, CH2CO); 3.48 (2Н, t, J = 6.3, S–CH2); 4.25 (2Н, br. s, NH2);
7.13 (2Н, m, Н-5,6 benzimidazole); 7.43 (2Н, m, H-4,7 benzimidazole);
9.07 (1Н, s, СОNH); 12.52 (1Н, s, NH benzimidazole)
5c
6
2.70 (2Н, t, J = 6.6, CH2CO); 3.50 (2Н, t, J = 6.6, S–CH2); 4.29 (2Н, d, J = 6.9,
CONHСН2,); 7.12-7.45 (9Н, m, C6H5 + H benzimidazole); 8.48 (1Н, t, J = 6.9, СОNH)
2.66 (4Н, t, J = 6.7, CH2CO); 4.23 (4Н, d, J = 6.8, 2CONHCH2); 4.52 (4Н, t, J = 6.7,
CH2–N); 7.12-7.25 (12Н, m, 2C6H5 + H-5,6 benzimidazole);
7.49 (2Н, m, Н-4,7 benzimidazole); 8.48 (2Н, t, J = 6.8, 2СОNH)
9
2.95 (1Н, m, Н-2); 3.23 (1Н, m, Н-2); 5.35 (1Н, m, Н-3); 6.85 (1Н, s, NH);
7.13-7.53 (10Н, m, C6H5 +NH + Н benzimidazole); 12.57 (1Н, s, NН benzimidazole)
10с
3.69 (3Н, s CН3O); 4.41 (2Н, d, J = 6.8, NHCH2); 6.54 (1Н, d, J = 13.2,
Ar–CН=); 6.99 (2Н, d, J = 8.6, p-C6H4); 7.32 (5Н, m, C6H5); 7.41 (1Н, d,
J = 13.2, =CH–CO); 7.54 (2Н, d, J = 8.6, p-C6H4); 8.55 (1Н, t, J = 6.8, СОNH)
11а
2.92 (2Н, m, Н-2); 4.12 (2Н, br. s, NH2); 5.40 (1Н, m, Н-3); 7.14-7.52 (9Н, m,
C6H5 + H benzimidazole); 9.08 (1Н, s, СОNH); 12.03 (1Н, br. s, NН benzimidazole)
11b
2.90 (2Н, m, Н-2); 3.74 (3Н, s CН3O); 4.15 (2Н, br. s, NH2); 5.35 (1Н, m, Н-3);
6.87 (2Н, d, J = 8.9, p-C6H4); 7.14 (2Н, m, H-5,6 benzimidazole);
7.36 (2Н, d, J = 8.9, p-С6H4); 7.46 (2Н, m, H-4,7 benzimidazole); 9.06 (1Н, s, СОNH);
11.72 (1Н, br. s, NН benzimidazole)
12a
12b
3.14 (2Н, m, Н-2); 5.38 (1Н, m, Н-3); 7.15-7.58 (14Н, m, 2C6H5 + 4H benzimidazole);
9.38 (1Н, br. s, CS–NH–Ar); 9.63 (1Н, s СОNH–NH); 10.19 (1Н, br. s, СОNH);
12.64 (1Н, s, NН benzimidazole)
2.77 (3Н, d, J = 3.1, СН3); 3.09 (2Н, m, CН2); 5.37 (1Н, m, SCH); 7.15 (2Н, m,
H-5,6 benzimidazole); 7.22-7.48 (6Н, m, С6Н5 + CS–NH);
7.51 (2Н, m, Н-4,7 benzimidazole); 9.24 (1Н, s, CO–NH–NH); 9.86 (1Н, s, СОNH);
12.65 (1Н, s, NН benzimidazole)
13
14
3.87 (2Н, m, CH2); 5.51 (1Н, m, SCH); 7.14-7.69 (15Н, m,
2C6H5 + NH + 4H benzimidazole); 12.53 (1Н, s, NН benzimidazole)
5.66 (2Н, s NCH2С6Н5); 7.35-7.51 (11Н, m, H arom + H benzimidazole);
7.80 (2Н, m, Н arom.); 7.88 (1Н, d, J = 13.4, С6Н5СН=);
7.96 (1Н, m, Н-7 benzimidazole); 8.13 (1Н, d, J = 13.4, CH=CO)
15
6.03 (4Н, s NCH2CO); 7.26 (2Н, m, Н-5,6 benzimidazole);
7.50 (2Н, m, Н-4,7 benzimidazole); 7.63-7.79 (6Н, m, H arom.);
8.14 (4Н, d, J = 7.9, Н arom.)
we obtained the product of alkylation at the two nitrogen atoms: 1,3-diphenacyl-2,3-dihydro-1H-
benz[d]imidazole-2-thione (15). Compound 15 is formed as a result of alkylation of 8a by 2-bromoacetophenone
even when an equimolar ratio of reagents is used. When thiazinobenzimidazolone 8a is treated with concentrated
hydrogen peroxide in acetic acid at 20°C, the products of oxidative decomposition of the 1,3-thiazine ring are
formed: benzimidazole-2-sulfonic acid (16) and cinnamic acid 17.
Thus the chemical properties and reactivity of compound 1 and 2-aryl-2,3-dihydro-4H-[1,3]thiazino-
[3,2-a]benzimidazol-4-ones 8a,b are significantly different. For compound 1, typical reactions are those
occurring primarily by breaking the C(4)–N(5) bond, while for 2-aryl[1,3]thiazino[3,2-a]benzimidazol-4-ones
8a,b, conversions accompanied by breaking of both the C(4)–N(5) bond and the S(1)–C(2) bond are more typical. In
the latter case, one of the reaction products is cinnamic acid 17 or its amides 10a-c, 14. The ease with which
400