Hydrochloric Acid → (3S)-1H,2H,3H,4H,9H-pyrido(3,4-b)indole-3-carboxylic acid

HRID 2171286Notes

Reaction equation

[CH2:1]=O.[NH2:3][C@H:4]([C:15]([OH:17])=[O:16])[CH2:5][C:6]1[C:14]2[C:9](=[CH:10][CH:11]=[CH:12][CH:13]=2)[NH:8][CH:7]=1.[OH-].[Na+].Cl>O>[CH2:1]1[C:7]2[NH:8][C:9]3[C:14]([C:6]=2[CH2:5][C@@H:4]([C:15]([OH:17])=[O:16])[NH:3]1)=[CH:13][CH:12]=[CH:11][CH:10]=3

Participants

Conditions

Temperature: 50 °C

Procedure

Formaldehyde (37% aq. solution, 39.7 mL, 490 mmol) was added to a stirred solution of L-tryptophan (100.0 g, 490 mmol) in aqueous sodium hydroxide solution (19.6 g in 200 mL of H2O, 490 mmol) and stirred for 2 hr. The mixture was heated to reflux and stirred for 3.5 hr. The mixture was cooled to 50° C. and carefully acidified to pH 5-6 with 6.0 M HCl(aq) solution. The mixture was diluted with water (200 mL). The flask was removed from heat and cooled to room temperature. The precipitates filtered off and washed with water. The solids were resuspended in THF (800 mL), stirred at RT for 1 hr, and filtered to afford compound 1 (101.3 g, 95%) as beige solid. 1H NMR (300 MHz, DMSO-d6): δ 10.93 (s, 1H), 8.88 (br s, 1H), 7.43 (d, 1H), 7.31 (d, 1H), 7.02 (t, 1H), 6.97 (t, 1H), 4.18 (q, 2H), 3.61-3.56 (m, 1H), 3.12 (dd, 1H), 2.83-2.75 (m, 1H); LC-MS [M+H+ 217].

Workup

temperatureThe mixture was heated
temperatureto reflux
stirringstirred for 3.5 hr
customThe flask was removed
temperaturefrom heat
temperaturecooled to room temperature
filtrationThe precipitates filtered off
washwashed with water
stirringstirred at RT for 1 hr
filtrationfiltered

Sources & evidence

ORD record: ord-afa5abd549cb4091b010a577d6a10815
Source dataset: uspto-grants-2015_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09051320B1

Reaction notes

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