Yield:-

Reaction Conditions:

with triphenylphosphine dibromide;N,N-dimethyl acetamide at 20; for 200 h;

Steps:

5

2,4-diamino-6-(hydroxymethyl)pteridine hydrochloride (4.40 g; 19.19 mmol) was dissolved in hot water (150 mL) and the solution was neutralized by addition of 1 M NaOH (ca. 20 mL). The precipitate was filtered, washed with water, and dried in vacuo over P2O5. Subsequently, this was suspended in DMAc (25 mL), and triphenylphosphine dibromide (18.12 g; 42.92 mmol) was added. The turbid reaction mixture was stirred for 20 hr at 20⁰C. 4-(Methylamino)benzoic acid (2.95 g; 19.50 mmol) and DIPEA (5.04 g; 39.00 mmol) were added, and the turbid reaction mixture was stirred for 3 days at 20⁰C. Then, it was poured in 0.33 M NaOH-solution (250 mL), the precipitate was filtered off, and the filtrate was neutralized by addition of 10% acetic acid in water (ca. 20 mL). The precipitate was filtered, washed with water, triturated with methanol (30 mL), and dried in vacuo over P2O5, to yield the product as a beige/orange powder (3.48 g; 56%).¹H-NMR (DMSO): δ 8.59 (s, IH), 7.53 (d, 2H, 8.8 Hz), 7.7 (br. s, IH), 7.5 (br. s, IH), 6.83 (d, 2H, 8.8 Hz), 4.79 (s, 2H), 3.23 (s, 3H) ppm. FT-IR (ATR): V 3335, 3194, 2964, 1651, 1597, 1292, 1187 cm^"1.

References:

WO2007/110811,2007,A2 Location in patent:Page/Page column 23