2H-Pyrazolo[3,4-d]pyriMidine, 4,6-dichloro-2-Methyl- synthesis

Yield:959432-77-0 66%

Reaction Conditions:

with trichlorophosphate for 24 h;

Steps:

Compound 299; 4,6-Dichloro-2-methyl-2H-pyrazolo[3,4-d]pyrimidine; Compound 297 (1.04 g, 5.7 mmol) was refluxed under argon with 50 mL phosphorous oxychloride for 24 hours. Following introduction of a pipette for analysis, the suspension became homogeneous after approximately an hour. Following homogeneity the reaction was refluxed an additional hour. Excess phosphorus oxychloride was then scrupulously removed in vacuo (high vacuum). Ice was added and the mixture neutralized to basic by addition of 1 ON sodium hydroxide solution. A yellow solid was removed by filtration and dried in vacuo to afford 0.76 g (66%). Compound 299: MS (ES⁺calculated: 203.03; found: 203.19 M+H). HPLC (67% purity-pdt decomposes on hplc column, retention time 6.895 minutes-Method A); ¹H NMR (400 MHz, DMSO-d⁶): δ 9.02 (s, 1H), 4.23 (s, 3H).

References:

US2007/281949,2007,A1 Location in patent:Page/Page column 90