GSK1120212 (DMSO solvate)

Description

In May 2013, the US FDA approved trametinib (also referred to as GSK1120212 and JTP-74057), for the treatment of patients with unresectable or metastatic melanoma with BRAF^V600e or BRAF^V600K mutations as detected by an FDA-approved test. Extensive lead optimization led to the identification of trametinib which is a potent ATP noncompetitive inhibitor of MEK1 and MEK2 (IC₅₀ =0.7 and 0.9 nM, respectively, with initially unphosphorylated MEK). It also showed inhibitory activity in ACHN and HT-29 cancer cell lines (IC_50s of 9.8 and 0.57 nM, respectively). Consistent with its in vitro activity, trametinib showed significant antitumor activity in a KRAS^G12S A549 tumor xenograft model where near to complete tumor growth inhibition (TGI) was observed at 5.0 and 2.5 mg/kg (92% and 87% TGI, respectively). Broad antitumor activity was seen in other xenograft models as well. A synthetic route to trametinib that employs a base catalyzed rearrangement of a pyrido[2,3-d]pyrimidine core to pyrido[4,3-d]pyrimidine, as a key step has been reported.

Originator

Japan Tobacco (Japan)

Uses

Trametinib (DMSO Solvate) is a highly potent and selective MEK inhibitor with significant antitumor activity.

Definition

ChEBI: An addition compound obtained by combining equimolar amounts of trametinib and dimethyl sulfoxide. Used for the treatment of patients with unresectable or metastatic melanoma with BRAF V600E or V600K mutations, and who have not received prior BRAF inhibito treatment.

brand name

Mekinist

Synthesis

Commercial 2-fluoro-4-iodoaniline (180) was sequentially subjected to CDI and cyclopropylamine to generate urea 181 in 96% yield. This was followed by coupling with cyanoacetic acid in the presence of mesyl chloride and DMF to furnish imide 182 in 96% yield. Under basic conditions, imide 182 underwent an intramolecular cyclization reaction to produce pyrimidine-2,4- dione 183 in 88% yield. Next, condensation with DMF¨CDMA generated formamidine 184 in 92% yield, and this was followed by NaBH4-mediated reduction and subsequent annulation with 2- methyl-malonic acid (186) to arrive at trione 187 in 58% from 184. Trione 187 was then treated with p-toluenesulfonyl chloride in Et3N, and the resulting tosylate was exposed to 30-aminoacetanilide (189) in the presence of 2,6-lutidine and DMA, inducing an addition-elimination reaction to give pyrido[2,3-d]pyrimidine 190 in 93% yield. The rearrangement of pyrido[2,3-d]pyrimidine 190 with sodium methoxide in THF/MeOH gave pyrido[4,3- d]pyrimidine (trametinib) in 89% yield. This was then complexed with a single equivalent of DMSO to produce trametinib DMSO (XXIV) in 92% yield.