Nitric Acid → 2,3-Dihydro-1'-acetyl-5-nitrospiro[benzofuran-2,4'-piperidine]

HRID 261505Notes

Reaction equation

[N+:1]([O-:4])(O)=[O:2].[C:5]([N:8]1[CH2:13][CH2:12][C:11]2([CH2:17][C:16]3[CH:18]=[CH:19][CH:20]=[CH:21][C:15]=3[O:14]2)[CH2:10][CH2:9]1)(=[O:7])[CH3:6].O>C(O)(=O)C>[C:5]([N:8]1[CH2:13][CH2:12][C:11]2([CH2:17][C:16]3[CH:18]=[C:19]([N+:1]([O-:4])=[O:2])[CH:20]=[CH:21][C:15]=3[O:14]2)[CH2:10][CH2:9]1)(=[O:7])[CH3:6]

Participants

Conditions

Temperature: 100 °C

Procedure

3.8 g of nitric acid (sp gr 1.42) in 30 ml of glacial acetic acid are added dropwise to a stirred solution of 4.7 g of 2,3-dihydro-1'-acetylspiro[benzofuran-2,4'-piperidine], Example 16, in 65 ml of glacial acetic acid. After total addition, the reaction mixture is slowly heated to 100° C. over a 2 hour span and then cooled and poured into 500 ml of water. The diluted mixture is extracted with chloroform and the chloroform extracts are washed sequentially with a saturated sodium bicarbonate solution, a saturated sodium chloride solution and then dried. The chloroform is removed under reduced pressure. The residue is triturated with ether, causing an orange precipitate which is collected and recrystallized first from an ethyl alcohol-ether mixture and then from ethyl alcohol to provide the product, 2,3-dihydro-1'-acetyl-5-nitrospiro[benzofuran-2,4'-piperidine], mp 149°-150° C.

Workup

additionAfter total addition
temperaturecooled
extractionThe diluted mixture is extracted with chloroform
washthe chloroform extracts are washed sequentially with a saturated sodium bicarbonate solution
dry with materiala saturated sodium chloride solution and then dried
customThe chloroform is removed under reduced pressure
customThe residue is triturated with ether
customis collected
customrecrystallized first from an ethyl alcohol-ether mixture

Sources & evidence

ORD record: ord-0fe34590c02f40798db12b495e8c8341
Source dataset: uspto-grants-1979_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04166119

Reaction notes

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