Hydrochloric Acid → 4,6-Dimethoxynaphthalene-1-carboxylic acid

HRID 1904097Notes

Reaction equation

ClCl.[OH-].[Na+].[CH3:5][O:6][C:7]1[C:16]2[C:11](=[CH:12][CH:13]=[C:14]([O:17][CH3:18])[CH:15]=2)[C:10]([C:19](=[O:21])C)=[CH:9][CH:8]=1.[OH:22]S([O-])=O.[Na+].Cl>O>[CH3:5][O:6][C:7]1[C:16]2[C:11](=[CH:12][CH:13]=[C:14]([O:17][CH3:18])[CH:15]=2)[C:10]([C:19]([OH:21])=[O:22])=[CH:9][CH:8]=1

Participants

Conditions

Temperature: 65 °C

Procedure

A stream of chlorine gas was passed through a cooled solution of NaOH (17.28 g, 0.432 mole) in water (24 ml) containing 100 g of ice until 12.7 g (0.18 mole) of chlorine was absorbed into the solution. Solid (4,6-dimethoxy-1-naphthalenyl)ethanone [9.2 g, 0.04 mole, described by N. P. Buu-Hoi, J. Org. Chem., 21, 1257 (1956)], was added at 20°-22° C. to the chlorine solution. The mixture was stirred at 65° C. for one hr, cooled in an ice bath and treated with NaHSO3 (5 g) in water (20 ml). The mixture was made neutral by the addition of dilute HCl. The resulting precipitate was collected, washed well with water, dried over P2O5 and recrystallized from methanol to give 4,6-dimethoxy-1naphthalenecarboxylic acid (7.0 g); mp 227°-229° C.; NMR (DMSO-d6) δ3.85 (s, 3H), 4.0 (s, 3H), 7.7 (m, 5H); IR (white mineral oil) 2900, 1670 cm-1 ; UVλmax (MeOH) 339 nm (ε4,910), 328 (4500), 304 (8,180), 240 (40,100); Anal Calcd: C, 67.23% H, 5.21%; Found: C, 67.15% H, 5.23%.

Workup

customwas absorbed into the solution
temperaturecooled in an ice bath
customThe resulting precipitate was collected
washwashed well with water
dry with materialdried over P2O5
customrecrystallized from methanol

Sources & evidence

ORD record: ord-c7f4ed1aa19345dfa8afc1d4ceb66dff
Source dataset: uspto-grants-1984_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04439617

Reaction notes

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