6-Methoxycarbonylmethoxy-5-nitro-nicotinic acid ethyl ester → 2-Oxo-2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazine-7-carboxylic acid ethyl ester

HRID 2386739Notes

Reaction equation

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

Participants

Conditions

Temperature: 60 °C

Procedure

To a solution of 6-methoxycarbonylmethoxy-5-nitro-nicotinic acid ethyl ester (3.271 g) in acetic acid (25 ml) was added iron powder (9.64 g). The mixture was stirred for 2 h at 60° C. The mixture was filtered and the filter cake was washed with acetic acid, EtOAc, EtOH, dichloromethane and with MeOH. The filtrate was concentrated. The residue was suspended in CH2Cl2/MeOH 9:1 and passed with more of the same solvent mixture over silica gel to give the title compound (1.52 g) as a light brown solid. MS (m/e)=223.1 [M+H+].

Workup

filtrationThe mixture was filtered
washthe filter cake was washed with acetic acid, EtOAc, EtOH, dichloromethane and with MeOH
concentrationThe filtrate was concentrated

Sources & evidence

ORD record: ord-7ab3f6dd0f6c40abadaef1706102c314
Source dataset: uspto-grants-2012_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08268820B2

Reaction notes

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