882
L. BUKOWSKI ET AL.
Table 1 1H and 13C NMR data of some of the new compounds
δ (ppm), J (Hz)
Solvent
CDCl3
4
3.26 (d, J = 4.7, 3H, NHCH3), 4.00 (s, 3H, NCH3), 7.24 (m, 1H, C(6)H), 7.51 (d, J = 8.2,
1H, C(7)H), 8.3 (d, J = 5.0, 1H, C(5)H)
13C NMR: 32.6, 32.7, 64.7, 116.3, 119.0, 120.6, 126.0, 143.4, 144.7, 153.6, 189.0
3.36 (d, J = 4.8, 4H, (CH2)2), 3.49 (s, 3H, NCH3), 3.87 (s, 3H, NCH3), 7.14 (dd, J1 = 4.8,
J2 = 7.0, 1H, C(6)H), 7.38 (d, J = 6.7, 1H, C(7)H), 8.40 (d, J = 3.6, 1H, C(5)H)
3.68 (s, 3H, NCH3), 3.82 (s, 3H, NCH3), 7.19 (dd, J1 = 4.8, J2 = 5.4, 1H, C(6)H), 7.94
(d, J = 7.8, 1H, C(7)H), 8.01 (s, 2H, NH2), 8.30 (d, J = 4.4, 1H, C(5)H)
4.16 (s, 3H, NCH3), 7.41 (m, 3H, Ar H), 7.49 (dd, J1 = 5.8, J2 = 4.4, 1H, C(6)H), 7.57
(t, J = 7.8, 2H, Ar H), 8.27 (d, J = 7.8, 1H, C(7)H), 8.62 (d, J = 5, 1H, C(5)H)
3.94 (s, 3H, NCH3), 4.50 (s, 2H, CH2Cl), 7.42 (dd, J1 = 5.4, J2 = 7.8, 1H, C(6)H), 8.19
(d, J = 8.3, 1H, C(7)H), 8.36 (d, J = 4.3, 1H, C(5)H), 13.45 (s, 1H, NH)
13C NMR: 32.2, 46.5, 64.3, 119.0, 119.6, 120.1, 125.7, 143.1, 144.6, 185.1
3.69 (s, 3H, NCH3), 3.85 (s, 2H, CH2 ), 6.14 (s, 2H, CH2 ), 7.12 (dd, J1 = 5.3, J2
= 7.8, 1H, C(6)H), 7.83 (d, J = 7.8, 1H, C(7)H), 8.25 (d, J = 4.4, 1H, C(5)H)
3.78 (s, 3H, NCH3), 6.40 (s, 1H, CH), 7.20 (dd, J1 = 4.8, J2 = 4.7, 1H, C(6)H), 7.53 (s,
1H, CH), 7.75 (m, 4H, Ar H), 7.95 (d, J = 1.3, 1H, C(7)H), 8.31 (d, J = 1.3, 1H,
C(5)H), 12.2 (br s, 1H, Ar OH)
10
14
16
18
CDCl3
DMSO-d6
DMSO-d6
DMSO-d6
22
23
DMSO-d6
DMSO-d6
26
30
DMSO-d6
DMSO-d6
3.85 (s, 3H, CH3), 4.52 (s, 2H, CH2), 7.33 (dd, J1 = 5, J2 = 7, 1H, C(3)H), 8.04 (d, J = 7.
1H, C(4)H), 8.23 (d, J = 5, 1H, C(2)H)
3.45 (s, 3H, NCH3), 3.86 (s, 3H, NCH3), 4.62 (s, 2H, CH2), 7.28 (dd, J1 = 4.7, J2 = 8.1H,
C(6)H), 8.03 (d, J = 7, 1H, C(7)H), 8.38 (d, J = 6, 1H, C(5)H)
at about 320 ◦C. This observation suggested the possibility of a cyclization. This was con-
firmed experimentally: a sample of compound 18 was heated at 250 ◦C for about 5 min (until
the decomposition was complete) and the product obtained after cooling was recrystallized
1
and investigated. Based on the IR, H NMR, and MS spectra, we established that com-
pound 18 loses a molecule of HCl at its melting temperature and undergoes intramolecular
cyclization to yield a new heterocyclic system, pyrrolo[2ꢁ,1ꢁ: 2,3]imidazo[4,5-b]pyridine 26
(Scheme 3). It is worth to note that according to 1H NMR data compound 23 exists in the
isomeric enole form (Table 1).
Scheme 3
In a further set of experiments, reaction of hydrazide 3 with methyl-, phenyl-, or
p-chlorophenyl isothiocyanate yielded the corresponding acyl-thiosemicarbazides 27–29.
Their cyclization in alkaline medium allowed us to prepare the 1,2,4-triazole derivatives
30–32.