Hydrochloric Acid → (4-Isopropylphenyl)hydrazine

To a stirred suspension of dimethyl 7-chloro-4-hydroxyquinoline- 2,3-dicarboxylate (2.01 g, 6.80 mM) and 4-isopropylphenyl hydrazine hydrochloride (8.90 g, 47.6 mM) in ethanol (72 mL) was added triethylamine(7.6 mL, 54.5 mH) to give a brown solution. This solution was refluxed for 16 hours, cooled to room temperature, and then added slowly to a mixture of hydrochloric acid (12N, 100 mL) and ice (100 mL) with vigorous stirringwhereupon a pink suspension formed. The suspension was filtered, and the collected solids were washed with a cold solution made by mixing methanol (100 mL), hydrochloric acid (100 mL, 12N) and ice (100 g) to give the 4-isopropylphenyl hydrazine salt of the title compound as a purple powder (1.80 g). This material was refluxed in glacial acetic acid (15 mL) for 3 hours to give a tan suspension. The suspension was cooled to room temperature and filtered. The collected solids were washed with glacial acetic acid (10 mL) and ether to give the title compound (1.125 g, 43%) asa tan powder, mp 367°-369° C.; MS(CI): 382 (M+H). Analysis for C20H16ClN3O3 ·0.1 H2O: Calculated: C, 62.60; H, 4.26; N, 10.95; Found: C, 62.60; H, 4.35; N, 10.73; NMR: 13.82 (v br s, 1H exchangeable), 8.41 (s, 1H exchangeable), 8.23 (d, J=8.64 Hz, 1H), 7.89 (d, J=1.98 Hz, 1H), 7.61 (dd, J=1.98, 8.64 Hz, 1H), 7.04 (d, J=8.42 Hz, 2H), 6.74 (d, J=8.42 Hz, 2H), 2.78 (septet, J=6.87 Hz, 1H), 1.15 (d, J=6.87 Hz, 6H).

1. customto give a brown solution
2. temperatureThis solution was refluxed for 16 hours
3. customformed
4. filtrationThe suspension was filtered
5. washthe collected solids were washed with a cold solution
6. additionby mixing methanol (100 mL), hydrochloric acid (100 mL, 12N) and ice (100 g)

ORD record

ord-fd1dfd22727643dab6c489094b37d65c

Source dataset

uspto-grants-1998_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05744471