Methyl acetoacetate → 2-Acetyl-3-benzofurazan-4-yl-acrylic acid methyl ester

HRID 2054705Notes

Reaction equation

[N:1]1[O:2][N:3]=[C:4]2[C:9]([CH:10]=O)=[CH:8][CH:7]=[CH:6][C:5]=12.[C:12]([O:18][CH3:19])(=[O:17])[CH2:13][C:14]([CH3:16])=[O:15]>C(OC(C)C)(C)C.N1CCCCC1>[CH:4]([O:15][CH:14]([CH3:16])[CH3:13])([CH3:9])[CH3:5].[CH3:19][O:18][C:12](=[O:17])[C:13]([C:14](=[O:15])[CH3:16])=[CH:10][C:9]1[C:4]2=[N:3][O:2][N:1]=[C:5]2[CH:6]=[CH:7][CH:8]=1

Participants

Conditions

Temperature: 70 °C

Procedure

Suspended 2,1,3-benzoxadiazole-4-carboxaldehyde (50 g, 0.33 mote) in diisopropyl ether (1300 ml) and added methyl acetoacetate (38 g, 0.32 mole), piperidine (2 g) glacial acetic acid (6 g) in to the suspension one after another. Refluxed the reaction mixture at 70° C. with continuous water separation. Removed sample from the reaction mixture and analysed the samples by qualitative HPLC. Washed the reaction mixture with hydrochloric acid (˜3.5 wt %, 250 ml, sodium bicarbonate solution (˜10 wt %, 250 ml and water (250 ml, 100 ml. Dried the organic layer over sodium sulphate (25 g) and then distilled diisopropyl ether under vacuum to get crude 2-acetyl-3-benzofurazan-4-yl-acrylic acid methyl ester (yield 70 g, HPLC purity 93.4%).

Workup

customwith continuous water separation
customRemoved sample from the reaction mixture
washWashed the reaction mixture with hydrochloric acid (˜3.5 wt %, 250 ml, sodium bicarbonate solution (˜10 wt %, 250 ml and water (250 ml, 100 ml
dry with materialDried the organic layer over sodium sulphate (25 g)

Sources & evidence

ORD record: ord-cb4edb9909424514a4113a74b40d4833
Source dataset: uspto-grants-2008_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07329756B2

Reaction notes

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