Glyoxylic Acid → (2E)-2-(pyridin-3-ylhydrazinylidene)acetic acid;hydrochloride

Temperature

22 °C

Glyoxylic acid (50% in water) (54.5 mL, 494 mmol) and 1 N hydrochloric acid (˜100 mL) were added to 3-hydrazinopyridine dihydrochloride (60.0 g, 330 mmol) and the reaction mixture was stirred at room temperature (about 22° C.) for 2 hours, at which point solid had started to precipitate. The reaction was stirred for 24 hours, at which point LC/MS indicated that it was complete. The mixture was transferred to a flask using acetonitrile (1 L). The mixture was azeotroped three times from acetonitrile (1 L). The resulting suspension was filtered to afford a green solid which was washed with acetonitrile and vacuum dried at 40° C. to afford the desired product (68.3 g, 98%): mp 173-174° C.; 1H NMR (400 MHz, DMSO-d6) δ 12.55 (d, J=1.2 Hz, 1H), 8.61 (d, J=2.5 Hz, 1H), 8.40 (dt, J=5.4, 0.9 Hz, 1H), 8.14 (ddd. J=8.7, 2.6, 1.2 Hz, 1H), 7.91 (dd, J=8.7, 5.4 Hz, 1H), 7.43 (d, J=1.0 Hz, 1H); 13C NMR (101 MHz, DMSO) δ 164.29, 143.15, 133.15, 131.85, 127.97, 127.61, 126.30; ESIMS m/z 166 ([M+H]+).

1. customto precipitate
2. stirringThe reaction was stirred for 24 hours, at which point LC/MS
3. customThe mixture was transferred to a flask
4. customThe mixture was azeotroped three times from acetonitrile (1 L)
5. filtrationThe resulting suspension was filtered
6. customto afford a green solid which
7. washwas washed with acetonitrile and vacuum
8. customdried at 40° C.

ORD record

ord-b3ec453ab2494901b6178728dab11ce4

Source dataset

uspto-grants-2016_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09434712B2