Phosphoric Acid → 4-(2-Chloro-pyrido[2,3-d]pyrimidin-4-yl)-piperazine-1-carboxylic acid tert-butyl ester

A mixture of 2,4-dichloro-pyrido[2,3-d]pyrimidine (150 mg, 0.75 mmol, 1 eq) [prepared from 2-aminonicotinic acid by the methods of Robins et al. (J. Am. Chem. Soc. 1955, 77, 1045.) and Oakes et al. (J. Chem. Soc. 1956, 1045.)], N-t-butoxycarbonyl piperazine (147 mg, 0.787 mmol, 1.05 eq) and Hunig's base (0.39 mL, 2.25 mmol, 3 eq) in ethanol (2.5 mL) was stirred at rt for 17 hr. The white solid was collected by filtration, washed with water and cold ethanol, and dried to afford C1.1 (105 mg, 40% yield). LC/MS: 350.41 [M+H]+; HPLC: >95% at 1.44 min (Xterra 5 μm C18 column 4.6×30 mm, 10-90% aqueous methanol over 2 min containing 0.2% phosphoric acid, 5 mL/min, monitoring at 254 nm).

1. filtrationThe white solid was collected by filtration
2. washwashed with water and cold ethanol
3. customdried
4. customto afford C1.1 (105 mg, 40% yield)

ORDレコード

ord-876a0a34330d467ca003e40da1d273aa

出典データセット

uspto-grants-2011_07

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US07981881B2