Piperazine → 4-(7-Piperazin-1-yl-quinazolin-4-yl)-piperidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A mixture of piperazine (5 mmol) and 4-(7-fluoro-quinazolin-4-yl)-piperidine-1-carboxylic acid tert-butyl ester (1 mmol) in DMSO (1 mL) was stirred at 120° C. for 1 h. It was then diluted with water and extracted with DCM. The combined extracts were washed with water, brine, dried (anhydrous MgSO4), filtered and concentrated in vacuo to obtain 4-(7-piperazin-1-yl-quinazolin-4-yl)-piperidine-1-carboxylic acid tert-butyl ester. This (0.1 mmol) was dissolved in anhydrous DCM (1 mL) and treated with Et3N (0.2 mmol) followed by 9-fluorenylmethyl chloroformate (FMOC-Cl, 0.2 mmol) and the mixture was stirred at rt overnight and then washed with water thrice, then dried over anhydrous MgSO4, filtered and concentrated in vacuo. To this was then added 3M HCl/MeOH (2 mL) and stirred at rt for 2 h and then concentrated in vacuo. The crude residue was dissolved in a mixture of DCM:MeOH (1:1; 2 mL) and neutralized with excess Et3N and treated with (4-morpholin-4-yl-phenyl)-carbamic acid 4-nitrophenyl ester hydrochloride (0.11 mmol), as prepared by the method outlined in Example 66a, at rt overnight. It was then concentrated in vacuo and the crude product was dissolved in DCM and washed with water thrice, then washed with brine, dried over anhydrous MgSO4, filtered and concentrated in vacuo. The crude product was then purified by Preparative TLC (silica gel; DCM:MeOH:NH4OH, 90:9:1) to obtain 5.6 mg (11%) of the title compound. 1H-NMR (300 MHz, CDCl3): 9.04 (s, 1H), 7.97 (d, 1H), 7.36-7.18 (m, 4H), 6.88 (d, 2H), 6.31 (s, 1H), 4.25 (m, 2H), 3.89-3.82 (m, 4H), 3.70-3.56 (m, 1H), 3.46-3.38 (m, 4H), 3.19-3.04 (m, 10H), 2.21-1.90 (m, 5H). LC/MS (ESI): 502.1 (MH)+.

Provenance & Evidence