Design, synthesis, and in vitro antiproliferative and kinase inhibitory effects of pyrimidinylpyrazole derivatives terminating with arylsulfonamido or cyclic sulfamide substituents

Figures & data

Figure 1. Structures of SB203580, Encorafenib (LGX818), and rationale design to the target compounds 1a–l and 2a–l.

Scheme 1. Reagents and conditions: (a) (i) triethylamine, CH₂Cl₂, 0 °C, RT, overnight; (ii) N-ethyl ethylenediamine, C₅H₅N, reflux, 3 h; (iii) benzyloxycarbonyl chloride, TEA, CH₂Cl₂, 0 °C; (iv) methanesulfonyl chloride, TEA, CH₂Cl₂, 0 °C; (v) IV, NaH (60% dispersion in mineral oil), DMF; (vi) H₂/Pd-C, MeOH, RT, 1 h; (b) (CH₃)₂SO₄, K₂CO₃, acetone, reflux, 3 h; (c) KMnO₄, C₅H₅N, H₂O, 50 °C, 24 h, then RT, 13 h; (d) acetyl chloride, CH₃OH, RT, 15 h; (e) 4-methyl-2-(methylthio)pyrimidine, LiHMDS, THF, −78 °C, 2 h then RT, overnight; (f) (i) DMF-DMA, 80 °C, 3 h; (ii) phenylhydrazine, C₂H₅OH, RT, overnight; (g) oxone, MeOH, H₂O, RT, 16 h; (h) 3a–l, diisopropylethylamine, DMSO, 80 °C, 16 h; (i) BBr₃, CH₂Cl₂, −78 °C, 1 h; RT, overnight.

Table 1. Structures of the target compounds 1a–l and 2a–l, their yield percentage, and melting points.

Table 2. Mean percentage growth of the 53 cancer cell line panel after treatment with the tested target compounds (10 μM concentration).

Compound No.	Mean percentage growth
1a	90.00
1d	33.29
1h	68.88
1i	88.81
1j	84.29
1k	94.93
1l	84.76
2f	67.91
2i	74.12
2k	99.38
2l	96.07

Bold figures indicate the most active compounds.

Figure 2. Percentage inhibition expressed by compounds 1d (a), 1h (b), and 2f (c) at 10 μM concentration over all cell lines of the NCI cancer cell line panel of nine different cancer types. The inhibition percentages are calculated by subtracting the growth percentages from 100.

Table 3. IC₅₀ (μM) results exerted by the compound 1d and staurosporine against HL-60 leukemia cell line, HT29 colon cancer cell line, and MRC-5 lung fibroblasts.

Cell line	IC50^a (μM) compound 1d	IC50 (nM) Staurosporine
HL-60 leukemia cell line	28.87	81.90
HT29 colon cancer cell line	13.37 (2.77)^b	186.0 (0.015)^b
MRC-5 lung fibroblasts  (normal cells)	37.02	2.8

^aIC₅₀ value means the concentration required to inhibit 50% of the cell growth.

^b Selectivity index calculated by dividing the IC₅₀ values against fibroblasts by IC₅₀ values against HT29 colon cancer cell line.

Table 4. Percentage inhibition and IC₅₀ (μM) results exerted by the most potent compounds over the selected kinases.

Kinase	Percentage inhibition at 10 μM concentration	IC50 (μM)
ABL1	7.31% ± 0.38%	ND
ABL1 (T315I)	−2.96% ± 0.60%	ND
FLT3	17.01% ± 0.42%	ND
V600E-B-RAF	74.47% ± 0.28%	3.57
RAF1	78.04% ± 0.32%	2.47
ALK5	7.90% ± 0.63%	ND
B-RAF (wild type)	6.26% ± 0.23%	ND
V600K-B-RAF	72.46% ± 0.37%	ND
EGFR	−3.57% ± 0.25%	ND
ERK2/MAPK1	−7.68% ± 1.96%	ND
JNK3	−3.07% ± 0.25%	ND
p38α/MAPK14	−26.57% ± 5.96%	ND