Synthesis, characterization and biological activity studies of certain 1-((benzo[d]thiazol-2-yl) methyl)-4,5-dihydro-3-methyl-N-phenyl-1H-pyrazol-5-imine and 2-((5-aryl-1H-1,2,4-triazol-3-yl) methyl)benzo[d]thiazoles

Figures & data

Scheme 1. Synthesis of 1-(benzo[d]thiazol-2-yl)methyl)-4,5-dihydro-3-methyl-N-1H-Pyrazol-5-imines-benzothiazole methyl N-pyrazole imines (3a-h).

Table 1. Synthesis and spectroscopic analysis of 1-((benzo[d]thiazol-2-yl)methyl)-4,5-dihydro-3-methyl-N-phenyl-1H-pyrazol-5-amines (3a-h)

Entry	XPhNH2 (X)	R.T (h)	Physical state	M.P (°C)	Yield (%)	^1HNMR (DMSO-d6); Mass (m/z); (M + H)
3a	–H	2	Solid	200–202	73	δ = 2.20 (s, 3H), 4.78 (s, 2H), 7.01 (d, 2H, J = 7.8 Hz), 7.18 (m, 4H, J = 7.2 Hz), 7.31 (t, 1H, J = 7.2 Hz), 7.40–7.60 (m, 4H, J = 7.8 Hz); m/z 322
3b	4-methoxy	5	Solid	198–200	80	δ = 2.21 (s, 3H), 3.76 (s, 3H), 4.80 (s, 2H), 7.02 (d, 2H, J = 8.1 Hz), 7.19 (m, 4H, J = 7.8 Hz), 7.38–7.60 (m, 4H, J = 8.1 Hz); m/z 353
3c	3-methoxy	6	Solid	196–197	79	δ = 2.20 (s, 3H), 3.78 (s, 3H), 4.80 (s, 2H), 7.01 (d, 2H J = 8.1 Hz), 7.20 (m, 4H J = 7.8 Hz), 7.38–7.61 (m, 4H, J = 8.1 Hz); m/z 353
3d	4-chloro	8	Solid	204–206	82	δ = 2.22 (s, 3H), 4.78 (s, 2H), 7.20 (d, 2H, J = 8 Hz),7.33 (m, 4H, J = 7.2 Hz), 7.42–7.65 (m, 4H, J = 8 Hz); m/z 357
3e	2-chloro	7	Solid	203–205	81	δ = 2.21 (s, 3H), 4.79 (s, 2H), 7.19 (m, 2H, J = 8 Hz), 7.34 (d, 4H, J = 7.4 Hz), 7.44–7.68 (m, 4H, J = 8 Hz); m/z 357
3f	4-bromo	3	Solid	200–202	80	δ = 2.20 (s, 3H), 4.81 (s, 2H), 7.20 (d, 2H, J = 7.4 Hz), 7.33 (m, 4H, J = 7.1 Hz), 7.44–7.67 (m, 4H, J = 7.4 Hz); m/z 401
3g	2-bromo	4	Solid	210–212	78	δ = 2.21 (s, 3H), 4.79 (s, 2H), 7.19 (d, 2H, J = 7.45 Hz), 7.34 (m, 4H, J = 7.15 Hz), 7.43–7.67 (m, 4H, J = 7.4 Hz).; m/z 401
3h	3-hydroxy	3	Solid	206–208	83	δ = 2.20 (s, 3H), 4.82 (s, 2H), 7.08 (d, 2H, J = 7.45 Hz), 7.32 (d, 2H, J = 7.45 Hz), 7.38 (m, 2H, J = 7.8 Hz), 7.45 (m, 2H, J = 7.8 Hz), 7.63 (d, 2H, J = 7.45 Hz), 9.80 (brs, 1H); m/z 339

Scheme 2. Synthesis of (IV) 2-(benzo[d]thiazol-2-yl)acetohydrazide [benzothiazole acetohydrazide]; (Va-h) 2-((5-arnyl-1H-1,2,4-triazol-3-yl)methyl)benzo[d]thiazoles[benzothiazole methyl aryl triazoles].

Table 2. Synthesis and spectroscopic analysis of 2-((5-phenyl-1H-1,2,4-triazol-3-yl)methyl)benzo[d]thiazoles (5a-h)

Entry	X-Ph-CHO (X)	R.T (h)	Physical state	M.P (°C)	Isolated yield (%)	^1HNMR (DMSO-d6); Mass (M + H).
5a	–H	3	Semi solid (Thick viscous)	210–212	80	δ = 4.91 (s, 2H), 7.40 (m, 1H, J = 8 Hz), 7.52 (m, 2H, J = 7 Hz), 7.78 (d, 2H, J = 8 Hz), 7.88 (d, 2H, J = 7 Hz), 8.10 (d, 2H, J = 8.5 Hz), 8.98 (brs, 1H); m/z 293
5b	4-methoxy	7	Semi solid (Thick viscous)	214–216	74	δ = 3.78 (s, 3H), 4.90 (s, 2H), 7.38 (m, 2H, J = 7.2 Hz), 7.48 (m, 2H, J = 7.2 Hz), 7.70 (d, 2H, J = 7.6 Hz), 8.90 (d, 2H, J = 8.0 Hz), 8.99 (brs, 1H); m/z 323
5c	3-methoxy	8	Semi solid (Thick viscous)	211–213	81	δ = 3.79 (s, 3H), 4.88 (s, 2H), 7.39 (m, 2H, J = 7.2 Hz), 7.47 (m, 2H, J = 7.2 Hz), 7.71 (d, 2H, J = 7.6 Hz), 8.91 (d, 2H, J = 8.0 Hz), 9.01 (brs, 1H); m/z 323
5d	4-chloro	6	Semi solid (Thick viscous)	198–200	80	δ = 4.87 (s, 2H), 7.22 (m, 2H, J = 8.0 Hz), 7.38 (m, 2H, J = 7.0 Hz), 7.68 (d, 2H, J = 8.0 Hz), 8.88 (d, 2H, J = 8.5 Hz), 9.20 (brs, 1H); m/z 328
5e	2-chloro	7	Semi solid (Thick viscous)	218–220	81	δ = 4.88 (s, 2H), 7.23 (m, 2H, J = 8.0 Hz), 7.39 (m, 2H, J = 7.0 Hz), 7.68 (d, 2H, J = 8.0 Hz), 8.89 (d, 2H, J = 8.5 Hz), 9.21 (brs, 1H); m/z 328
5f	4-bromo	5	Semi solid (Thick viscous)	215–217	79	δ = 4.88 (s, 2H), 7.23 (m, 2H, J = 7.4 Hz), 7.40 (m, 2H, J = 7.1 Hz), 7.69 (d, 2H, J = 7.4 Hz), 8.89 (d, 2H, J = 7.8 Hz), 9.21 (brs, 1H); m/z 372
5g	2-bromo	6	Semi solid (Thick viscous)	193–195	76	δ = 4.79 (s, 2H), 7.24 (m, 2H, J = 7.5 Hz), 7.41 (m, 2H, J = 7.2 Hz), 7.68 (d, 2H, J = 7.5 Hz), 8.88 (d, 2H, J = 7.9 Hz), 9.22 (brs, 1H); m/z 372
5h	3-hydroxy	4	Semi solid (Thick viscous)	220–222	73	δ = 4.80 (s, 2H), 7.25 (m, 2H J = 7.6 Hz), 7.40 (m, 2H J = 7.6 Hz), 7.70 (d, 2H J = 8.1 Hz), 8.90 (m, 2H J = 8.1 Hz), 9.20 (brs, 1H), 9.91(brs, 1H); m/z 372

Table 3. Antibacterial activity of 1-((benzo[d]thiazol-2-yl)methyl)-4,5-dihydro-3-methyl-N-aryl-1H-pyrazol-5-amines and 2-((5-aryl-1H-1,2,4-triazol-3-yl)methyl)benzo[d]thiazoles

Entry	Zone of inhibition (mm)
	Species used for activity screening
	Sp1	Sp2	Sp3	Sp4
Compound	S. aureus	Klebsiella pneumoniae	Salmonella paratyphi A	Salmonella paratyphi B
3a	8	7	6	1
3b	12	13	7	2
3c	6	1	1	1
3d	17	5	1	6
3e	1	3	2	1
3f	17	10	11	1
3g	2	8	6	8
3h	9	10	7	11
5a	5	4	1	1
5b	2	1	2	1
5c	1	2	1	1
5d	2	2	1	2
5e	1	1	1	2
5f	4	1	2	6
5g	1	12	11	12
5h	2	13	11	10
Tetracycline	25	18	16	10