Indole-based hydrazide-hydrazones and 4-thiazolidinones: synthesis and evaluation as antitubercular and anticancer agents

Figures & data

Figure 1. The structure of actithiazic acid (a) and apoptosis inducers (b).

Figure 2. Normal-phase HPLC diastereomeric resolution of compounds 8b, 8i, 8k and 8l. Column: Kromasil 100-5SIL microporous silica column (25 cm × 4.6 mm); eluent: hexane–ethyl acetate (80:20); flow rate:1.2 mL/min; detection: 304 nm.

Scheme 1. Synthesis of 6–8. Reagents and conditions: (i) 7% NaNO₂, EtOH, conc. HCl, 0 °C; (ii) ethyl 2-benzyl-3-oxo-butanoate, KOH, EtOH, 0 °C; (iii) conc. HCl, reflux, 4 h; (iv) H₂NNH₂·H₂O, EtOH, reflux, 6 h; (v) (non)substituted benzaldehyde, abs. EtOH, reflux, 5–6 h; (vi) mercaptoacetic acid, dry benzene, reflux, 5–6 h and (vii) 2-mercaptopropionic acid, dry benzene, reflux, 5–6 h.

Table 1. Retention times and peak area percentages of compounds 7–8b, 8i, 8k, 8l in NP-HPLC.^a

	7b	7i	7k	7l	8b	8i	8k	8l
Retention time  (min) (Peak-area  percentage)	29.51 (100%)	23.75 (100%)	21.75 (100%)	23.69 (100%)	13.88 (23.49%)	16.63 (66.05%)	8.47 (94.27%)	11.25 (84.82%)
					19.30 (76.51%)	27.92 (33.95%)	12.27 (5.73%)	15.28 (15.18%)

^aColumn: Kromasil 100-5SIL microporous silica column (25 cm × 4.6 mm); eluent: hexane–ethyl acetate (80:20); flow rate: 1.2 mL/min; detection: 304 nm.

Table 2. In vitro antitubercular activity and cytotoxicity screening results of compounds 6–8.

Compound	R	R1	R2	R3	MIC (µg/ml)^a	IC50 (µg/ml)^b
6b	H	CH3	H	–	>25	NT^c
6c	H	OCH3	H	–	>25	NT
6i	H	CF3	H	–	>25	NT
6j	H	COOCH3	H	–	>25	NT
6k	Cl	H	Cl	–	>25	NT
6l	Cl	H	F	–	>25	NT
7a	H	H	H	H	>25	NT
7b	H	CH3	H	H	>25	NT
7c	H	OCH3	H	H	>25	NT
7d	H	Cl	H	H	>25	NT
7e	H	Br	H	H	>25	NT
7f	H	F	H	H	>25	NT
7g	H	CN	H	H	6.25	113.4
7h	H	NO2	H	H	6.25	> 125
7i	H	CF3	H	H	12.5	> 250
7j	H	COOCH3	H	H	25.0	> 125
7k	Cl	H	Cl	H	>25	NT
7l	Cl	H	F	H	>25	NT
8a	H	H	H	CH3	>25	NT
8b	H	CH3	H	CH3	>25	NT
8c	H	OCH3	H	CH3	>25	NT
8d	H	Cl	H	CH3	>25	NT
8e	H	Br	H	CH3	>25	NT
8f	H	F	H	CH3	>25	NT
8g	H	CN	H	CH3	12.5	60.0
8h	H	NO2	H	CH3	12.5	125.0
8i	H	CF3	H	CH3	>25	NT
8j	H	COOCH3	H	CH3	25.0	>250
8k	Cl	H	Cl	CH3	>25	NT
8l	Cl	H	F	CH3	>25	NT
Rifampicin	–	–	–	–	0.25	>250

^aMIC, minimum inhibitory concentration required to inhibit the growth of 99% of M. tuberculosis H37Rv (ATCC 27294).

^bIC₅₀, 50% cytotoxic concentration against NRK-52E cells in vitro.

^cNT, not tested.

Values in bold indicate the MIC and IC₅₀ values of the most active compounds 7g–j, 8g, 8h and 8j.

Table 3. In vitro anticancer activity of compound 6b against 60 human tumor cell lines at five-dose levels in comparison with data of NCI's standard 5-fluorouracil.^a

	NSC 752358 (6b)			NSC 19893 (5-fluorouracil)
Panel/cell line	GI50^b	TGI^c	LC50^d	GI50	TGI	LC50
Leukemia
CCRF-CEM	0.033	>100	>100	10.0	100.0	100.0
HL-60(TB)	0.026	0.072	>100	2.51	100.0	100.0
K-562	0.038	15.5	>100	4.00	100.0	100.0
MOLT-4	0.038	15.5	70.8	0.32	50.1	100.0
RPMI-8226	0.033	13.8	>100	0.050	50.1	100.0
SR	0.028	40.7	>100	0.025	10.0	100.0
Non-small cell lung cancer
A549/ATCC	0.034	>100	>100	0.20	63.1	100.0
EKVX	0.074	>100	>100	63.1	100.0	100.0
HOP-62	0.033	0.81	>100	0.40	100.0	100.0
HOP-92	0.036	30.2	>100	79.4	100.0	100.0
NCI-H23	0.031	19.1	>100	0.32	39.8	100.0
NCI-H322M	0.039	26.9	>100	0.20	7.94	100.0
NCI-H460	0.036	14.5	>100	0.063	50.1	100.0
NCI-H522	0.013	0.040	>100	7.94	63.1	100.0
Colon cancer
COLO 205	0.018	0.034	0.063	0.16	63.1	100.0
HCC-2998	0.030	21.4	>100	0.050	39.8	100.0
HCT-116	0.023	0.069	>100	0.25	3.98	25.1
HCT-15	0.025	0.083	>100	0.10	50.1	100.0
HT29	0.025	NT^e	>100	0.16	63.1	100.0
KM12	0.025	0.066	17.4	0.20	39.8	100.0
SW-620	0.039	>100	>100	1.00	100.0	100.0
CNS cancer
SF-268	1.32	34.7	>100	1.58	100.0	100.0
SF-295	0.019	0.060	50.1	0.25	3.98	100.0
SF-539	0.025	0.070	38.0	0.063	79.4	100.0
SNB-19	0.050	>100	>100	4.00	79.4	100.0
SNB-75	0.032	11.7	83.2	79.4	100.0	100.0
U251	0.036	34.7	>100	1.00	79.4	100.0
Melanoma
LOX IMVI	0.028	>100	>100	0.25	50.1	79.4
MALME-3M	0.067	66.1	>100	0.050	2.51	100.0
M14	0.022	0.061	>100	1.00	100.0	100.0
MDA-MB-435	0.021	0.048	2.75	0.079	79.4	100.0
SK-MEL-2	0.031	NT	>100	63.1	100.0	100.0
SK-MEL-28	0.25	>100	>100	1.00	63.1	100.0
SK-MEL-5	0.020	0.045	0.29	0.50	39.8	79.4
UACC-257	0.061	>100	>100	4.00	79.4	100.0
UACC-62	0.042	34.7	>100	0.50	39.8	100.0
Ovarian cancer
IGROV1	0.032	1.82	>100	1.26	31.6	100.0
OVCAR-3	0.025	0.048	NT	0.015	0.32	50.1
OVCAR-4	0.046	>100	>100	4.00	79.4	100.0
OVCAR-5	0.050	>100	>100	10.0	50.1	100.0
OVCAR-8	0.037	>100	>100	1.58	31.6	100.0
NCI/ADR-RES	0.022	0.053	>100	0.32	12.6	100.0
SK-OV-3	0.027	0.077	>100	19.9	63.1	100.0
Renal cancer
786-0	0.031	12.3	>100	0.79	50.1	100.0
A498	0.038	24.5	>100	0.40	100.0	100.0
ACHN	0.048	>100	>100	0.32	31.6	100.0
CAKI-1	0.033	3.63	>100	0.079	2.00	100.0
RXF 393	0.025	0.085	63.1	2.51	31.6	100.0
SN12C	0.045	>100	>100	0.50	25.1	100.0
TK-10	0.044	>100	>100	1.26	79.4	100.0
UO-31	0.038	21.4	>100	1.58	50.1	100.0
Prostate cancer
PC-3	0.034	20.4	>100	2.51	100.0	100.0
DU-145	0.023	0.052	0.29	0.40	100.0	100.0
Breast cancer
MCF7	0.029	>100	>100	0.079	50.1	100.0
MDA-MB-231/ATCC	0.033	0.23	>100	6.31	39.8	100.0
HS 578T	0.027	1.78	>100	10.0	100.0	100.0
BT-549	0.032	2.34	>100	10.0	100.0	100.0
T-47D	24.0	>100	>100	7.94	50.1	100.0
MDA-MB-468	0.023	0.067	>100	NT	NT	NT
MG_MID^f	0.039	4.37	63.1	0.85	42.7	95.5

^aData obtained from the NCI's in vitro disease-oriented human tumor cell screen. All values were given in µM. Highest concentration was 100 µM unless otherwise reported.

^bMolar concentration that inhibited 50% net cell growth.

^cMolar concentration leading to total growth inhibition.

^dMolar concentration leading to 50% cell death.

^eNot tested.

^fAverage activity parameter over all cell lines.