P-Xylene → 2-(5-Nitrothiophen-2-yl)oxazolo[5,4-c]pyridine

HRID 419893Notes

Reaction equation

O[C:2]1[CH:3]=[N:4][CH:5]=[CH:6][C:7]=1[NH:8][C:9]([C:11]1[S:12][C:13]([N+:16]([O-:18])=[O:17])=[CH:14][CH:15]=1)=[O:10].O=P12OP3(OP(OP(O3)(O1)=O)(=O)O2)=O.CC1C=CC(C)=CC=1>N1C=CC=CC=1>[N+:16]([C:13]1[S:12][C:11]([C:9]2[O:10][C:2]3[CH:3]=[N:4][CH:5]=[CH:6][C:7]=3[N:8]=2)=[CH:15][CH:14]=1)([O-:18])=[O:17]

Participants

Conditions

Temperature: 160 °C

Procedure

To a stirred solution of N-(3-hydroxypyridin-4-yl)-5-nitrothiophene-2-carboxamide (1.1 g, 4.1 mmol) in pyridine (5 mL) was added P2O5 (1.2 g, 8.3 mmol) and p-xylene (21 mL). After refluxing at 160° C. overnight, the reaction mixture was concentrated in vacuo and the residue was purified by chromatography on silica gel eluted with 5% of ethyl acetate in CH2Cl2 to give 2-(5-nitrothiophen-2-yl)oxazolo[5,4-c]pyridine as brown solid (174 mg, yield 17%). 1H NMR (400 MHz, CDCl3) δ: 8.97 (1H, s); 8.59 (1H, d, J=5.6); 7.94 (1H, d, J=4.4); 7.86 (1H, d, J=4.4), 7.69 (1H, d, J=5.6,0.8).

Workup

concentrationthe reaction mixture was concentrated in vacuo
customthe residue was purified by chromatography on silica gel
washeluted with 5% of ethyl acetate in CH2Cl2

Sources & evidence

ORD record: ord-eb7eed0b95864ad38256ac6172b4b41a
Source dataset: uspto-grants-2012_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08093401B2

Reaction notes

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