2-methyl derivatives 6 and 16. Moreover, under these conditions (in contrast to those reported before) we have
been able to separate and to identify the product of the noted two-stage C–C recyclization as the 6-carboxy-
2,7-dimethylpyrazolo[1,5-a]pyrimidine (23) and the final reaction product, i.e. the 2,7-dimethylpyrazolo-
[1,5-a]pyrimidine (24). Separation of the 6-carboxy-2,7-dimethylpyrazolo[1,5-a]pyrimidine (23) is a direct,
rather than indirect, proof of the existence of a two-stage C–C recyclization.
TABLE 2. 1H and 13C NMR Spectra of the Condensed Pyrimidines 6-24
Com-
pound
Chemical shifts, δ, ppm (J, Hz)
1.44 (3Н, t, J = 7.1, ОСН2СH3); 2.56 (3Н, s, 2-СН3); 3.20 (3Н, s, 7-СН3);
4.44 (2Н, q, J = 7.1, ОСН2СН3); 6.55 (1Н, s, Н-3); 8.91 (1Н, s, Н-5)
6*
7
1.47 (3Н, t, J = 7.1, ОСН2СH3); 3.28 (3Н, s, 7-СН3); 4.47 (2Н, q, J = 7.1, ОСН2CH3);
7.30 (1Н, s, Н-3); 7.37-7.41 (2Н, m, С6Н4); 7.53 (1H, m, C6H4); 7.97 (1H, m, C6H4),
8.99 (1Н, s, Н-5)
1.44 (3Н, t, J = 7.1, ОСН2СH3); 3.26 (3Н, s, 7-СН3); 4.46 (2Н, q, J = 7.1, ОСН2);
7.30 (1Н, s, Н-3); 7.41-7.79 (4Н, m, С6Н4); 8.99 (1Н, s, Н-5)
8
1.40 (0.6H, t, J = 7.1, OСН2СH3); 2.45 (0.6H, s, CH3); 4.34 (0.4H, q, J = 7.1, OСН2СH3);
9
6.19 (0.2H, s, H-3); 8.13 (0.2H, br. s, NH2) and 8.36 (0.2H, br. s, NH2); 8.53 (0.2H, s, H-5)
1.35 (3Н, t, J = 7.1, ОСН2СH3); 4.21 (2Н, q, J = 7.1, ОСН2СH3); 8.18 (1H, br. s, H-2);
8.61 (1H, d, J = 13.5, H-5); 11.35 (1H, d, J = 13.5, NH); 13.65 (1H, br. s, NH)
11
12
13
1.47 (3Н, t, J = 7.1, ОСН2СH3); 2.67 (3H, s, 2-CH3); 3.37 (3H, s, 7-CH3);
4.45 (3H, s, N-CH3); 4.51 (2Н, q, J = 7.1, ОСН2СH3); 7.33 (1H, s, H-3); 9.78 (1H, s, H-5)
1.51 (3Н, t, J = 7.1, ОСН2СH3); 1.65 (3Н, t, J = 7.1, NСН2СH3); 2.65 (3H, s, 2-CH3);
3.35 (3H, s, 7-CH3); 4.50 (2Н, q, J = 7.1, ОСН2СH3); 4.91 (2Н, q, J = 7.1, NСН2СH3);
7.43 (1H, s, H-3); 9.84 (1H, s, H-5)
1.33 and 1.37 (3H, t, J = 7.1, CH3); 4.21 and 4.28 (2H, q, J = 7.1, OCH2);
6.32 and 6.64 (1H, d, J = 2.1, H-4); 7.26-7.42 (3H, m, C6H5) and 7.64-7.69 (2H, m, C6H5);
8.27 and 8.57 (1H, d, J = 13.8, =CHNH); 10.75 (1H, d, J = 13.8, =CHNH);
12.82 and 12.94 (1H, d, J = 2.1, NH)
14a
and
14b
1.31 and 1.35 (2.4H, t, J = 7.1, OCH2CH3); 2.23 and 2.25 (2.4H, s, CH3);
4.19 and 4.25 (1.6H, q, J = 7.1, OCH2); 5.74 and 5.95 (0.8H, br. s, H-4 pyrazole);
8.14 and 8.49 (0.8H, d, J = 13.8, =CHNH); 10.56 and 10.62 (0.8H, d, J = 13.8, =CHNH);
11.98 and 12.12 (0.8H, br. s, NH)
15a
and
15b
2.49 (3H, s, 2-CH3); 3.13 (3H, s, COCH3); 6.41 (1H, s, H-3); 7.00 (1H, br. s, OH);
8.79 (1H, s, H-5)
16
17
18
19
3.23 (3H, s, CH3); 5.8-6.3 (1Н, br. s, ОН); 7.17 (1Н, s, Н-3); 7.38 (2Н, m, С6Н4);
7.51 (1Н, m, С6Н4); 7.98 (1Н, m, С6Н4); 8.90 (1Н, s, Н-5)
3.22 (3H, s, CH3); 7.17 (1H, s, H-3); 7.40-7.97 (4H, m, C6H4);
8.91 (1H, s, H-5); 12.4-13.3 (1H, br. s, OH)
8.34 (1Н, s, H-2); 8.62 (1Н, br. s, NH); 8.83 (1Н, s, Н-5); 8.88 (1Н, br. s, NH);
12.4-13.4 (1Н, br. s, ОН)
2.55 (3H, s, 2-CH3); 2.97 (3H, s, COCH3); 6.57 (1H, s, H-3); 8.68 (1H, s, H-5)
20
21*2
2.41 (3Н, s, СН3); 6.18 (1Н, s, Н-3); 8.03 (1Н, br. s, NH); 8.43 (1Н, br. s, NH);
8.55 (1Н, s, Н-5); 11.0-13.0 (1Н, br. s, ОН)
6.78 (1Н, s, Н-3); 7.4-8.0 (5Н, m, С6Н5); 8.18 (1Н, br. s, NH); 8.58 (1Н, br. s, NH);
8.59 (1Н, s, Н-5); 11.4-13.1 (1Н, br. s, ОН)
22
23
24
2.49 (3H, s, 2-CH3); 3.13 (3H, s, 7-CH3); 6.41 (1H, s, H-3); 8.79 (1H, s, H-5);
12.92 (1Н, br. s, COОН)
2.48 (3H, s, 2-CH3); 2.72 (3H, d, J = 0.9, 7-CH3); 6.37 (1H, s, H-3);
6.68 (1H, dq, J = 4.2, J = 0.9, H-6); 8.24 (1H, d, J = 4.2, H-5)
_______
*
13C spectrum, δ, ppm: 14.43 (СН3СН2О); 14.99 (2-СН3); 15.19 (7-СН3);
61.54 (ОСН2); 97.76 (С-3); 109.89 (С-2); 149.51 (С-ipso); 149.78 (С-5);
150.98 (С-7); 157.38 (С-6); 165.10 (СОО).
*
2 13C spectrum, δ, ppm: 14.11 (CH3); 89.88 (CO–C); 95.94 (=CH); 148.70 (C-
7); 149.53 (C-4); 150.34 (N=CH), 154.36 (C-2); 167.99 (CO).
328