Carbon Dioxide → HCID 22051605, compound

Participants

Reaction Steps

A solution of 3-(4-{[2-(1H-indol-3-yl)-ethylamino]-methyl}-phenyl)-(2E)-2-propenoic acid methyl ester (12.6 g, 37.7 mmol), (2-bromoethoxy)-tert-butyldimethylsilane (12.8 g, 53.6 mmol), (i-Pr)2NEt, (7.42 g, 57.4 mmol) in DMSO (100 mL) is heated to 50° C. After 8 hours the mixture is partitioned with CH2Cl2/H2O. The organic layer is dried (Na2SO4) and evaporated. The residue is chromatographed on silica gel to produce 3-[4-({[2-(tert-butyldimethylsilanyloxy)-ethyl]-[2-(1H-indol-3-yl)-ethyl]-amino}-methyl)-phenyl]-(2E)-2-propenoic acid methyl ester (13.1 g). A solution of KOH (12.9 g (87% pure), 0.2 mol) in MeOH (100 mL) is added to a solution of HONH2.HCl (13.9 g, 0.2 mol) in MeOH (200 mL) and a precipitate results. After 15 minutes the mixture is filtered, the filter cake washed with MeOH and the filtrate evaporated under vacuum to approximately 75 mL. The mixture is filtered and the volume adjusted to 100 mL with MeOH. The resulting solution 2M HONH2 is stored under N2 at −20° C. for up to 2 weeks. Then 3-[4-({[2-(tert-butyldimethylsilanyloxy)-ethyl]-[2-(1H-indol-3-yl)-ethyl]-amino}-methyl)-phenyl]-(2E)-2-propenoic acid methyl ester (5.4 g, 11 mmol) is added to 2 M HONH2 in MeOH (90 mL, 180 mmol) followed by a solution of KOH (720 mg (87% pure), 11.2 mmol) in MeOH (5 mL) and the mixture stirred overnight. Dry ice is added to the reaction and the mixture diluted with H2O resulting in the formation of a precipitate. The liquid was decanted and the solid was dissolved in MeOH and filtered. The filtrate is evaporated to afford N-hydroxy-3-[4-({[2-(tert-butyldimethylsilanyloxy)-ethyl]-[2-(1H-indol-3-yl)-ethyl]-amino}methyl)-phenyl]-(2E)-2-propenamide (5.1 g,) which is used without further purification. The hydroxamic acid (5.0 g, 13.3 mmol) is then dissolved in 95% TFA/H2O (59 mL) and heated to 40-50° C. for 4 hours. The mixture is evaporated and the residue purified by reverse phase HPLC to produce N-Hydroxy-3-[4-[[(2-hydroxyethyl)[2-(1H-indol-3-yl)-ethyl]-amino]methyl]phenyl]-2E-2-propenamide as the trifluoroacetate salt (m/z 380 [MH+]).

Provenance & Evidence