1,1'-Thiocarbonyldiimidazole → tert-Butyl 4-carbamothioylpiperazine-1-carboxylate

To a solution of piperazine-1-carboxylic acid tert-butyl ester (32.2 mmol) in tetrahydrofuran (60 ml) was added thiocarbonyldiimidazole (37.0 mmol). The reaction was stirred at RT for 2 h then heated at 55° C. for 1 h. The reaction was concentrated in vacuo to approximately half the volume and methanolic ammonia added (7N, 107.4 mmol). The reaction was heated at 55° C. for 16 h. The reaction was concentrated in vacuo to approximately half the volume and cooled to 0° C. at which point the product precipitated from solution. The product was collected by filtration to yield the title compound as a white solid (3.3 g). 1H NMR (400 MHz, d6-DMSO) 1.40 (9H, s), 3.32 (4H, s), 3.71 (4H, s), 7.42 (1H,s).

1. temperaturethen heated at 55° C. for 1 h
2. concentrationThe reaction was concentrated in vacuo to approximately half the volume and methanolic ammonia
3. additionadded (7N, 107.4 mmol)
4. temperatureThe reaction was heated at 55° C. for 16 h
5. concentrationThe reaction was concentrated in vacuo to approximately half the volume
6. temperaturecooled to 0° C. at which point the product
7. customprecipitated from solution
8. filtrationThe product was collected by filtration

ORD record

ord-1520c75034704dbd9ca9dbc6bb1823a5

Source dataset

uspto-grants-2011_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07915300B2