Phosphorus oxychloride → Ethyl 4-chloro-7H-pyrrolo[2,3-d]pyrimidine-6-carboxylate

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Reaction Conditions

Reaction Steps

Under a N2 atmosphere, 32.0 g (154 mmol) of 6-ethoxycarbonyl-4-hydroxy-7H-pyrrolo[2,3-d]pyrimidine are suspended at RT in 308 ml (338 mmol) of POCl3 and, with stirring, heated at 120° C., during which the solid dissolves. After 3 hours' stirring at 120° C., the excess POCl3 is distilled off (65° C. external temperature; 15 mbar). The residue is suspended in 50 ml of ice-cold toluene, filtered and washed with toluene to yield the title compound; m.p. 219-221° C.; 1H-NMR (DMSO-d6) 8.77 and 7.24 (2s, 2H), 4.39 (q, J=7, 2H), 1.36 (t, J=7, 3H). Further product can be obtained from the filtrate by concentrating by evaporation and then stirring in ethyl acetate/water.

Provenance & Evidence