Ethyl orthopropionate → 7-bromo-1-ethyl-8-phenyl-4H-pyrido[2,3-b][1,2,4]triazolo[4,3-d][1,4]oxazine

HRID 1509313Notes

Reaction equation

[Br:1][C:2]1[C:3]([C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)=[CH:4][C:5]2[NH:10]/[C:9](=[N:11]/[NH2:12])/[CH2:8][O:7][C:6]=2[N:13]=1.C(O[C:23](OCC)(OCC)[CH2:24][CH3:25])C>>[Br:1][C:2]1[C:3]([C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)=[CH:4][C:5]2[N:10]3[C:23]([CH2:24][CH3:25])=[N:12][N:11]=[C:9]3[CH2:8][O:7][C:6]=2[N:13]=1

Participants

Reactant 2

HCID 66995Ethyl orthopropionate

HCID 178514315HCID 178514315, compound

Product 1

HCID 866836747-bromo-1-ethyl-8-phenyl-4H-pyrido[2,3-b][1,2,4]triazolo[4,3-d][1,4]oxazineYield 40%

Conditions

Temperature: 120 °C

Procedure

In a 10 ml microwave vial was (E)-6-bromo-2-hydrazono-7-phenyl-2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazine (90 mg, 0.282 mmol) in 1,1,1-triethoxypropane to give a yellow suspension. The reaction mixture was heated to 120° C. for 20 minutes. The crude residue was concentrated under reduced pressure and purified by Biotage silica gel chromatography (gradient 100% to 100% n-hexane in ethyl acetate) to give the title compound (41 mg, 40%). 1H NMR (500 MHz, CDCl3): 7.73 (1H, s), 7.54-7.48 (3H, m), 7.45-7.41 (2H, m), 5.56 (2H, s), 3.10-3.00 (2H, q), 1.53-1.48 (3H, t). LCMS (Method D) RT 1.117 min, M+1=358.

Workup

customto give a yellow suspension
concentrationThe crude residue was concentrated under reduced pressure
custompurified by Biotage silica gel chromatography (gradient 100% to 100% n-hexane in ethyl acetate)

Sources & evidence

ORD record: ord-3ccc4cef44a8454eaf27ff21acc5dea5
Source dataset: uspto-grants-2015_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09221838B2

Reaction notes

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