Formamide → [1]benzothieno[3,2-d]pyrimidin-4(3H)-one

Reaction equation

[NH2:1][C:2]1[C:3]2[CH:15]=[CH:14][CH:13]=[CH:12][C:4]=2[S:5][C:6]=1[C:7](OCC)=[O:8].[CH:16]([NH2:18])=O>>[N:1]1[C:2]2[C:3]3[CH:15]=[CH:14][CH:13]=[CH:12][C:4]=3[S:5][C:6]=2[C:7](=[O:8])[NH:18][CH:16]=1

Participants

Reactant 2

HCID 713Formamide

HCID 731510Ethyl 3-aminobenzo[b]thiophene-2-carboxylate

Product 1

HCID 135442517[1]benzothieno[3,2-d]pyrimidin-4(3H)-oneYield 61.2%

Conditions

Temperature: 190 °C

Procedure

A 100 mL RBF was charged with ethyl 3-aminobenzo[b]thiophene-2-carboxylate (17.7 g, 80 mmol), treated with formamide (60.6 mL, 1520 mmol) and heated to 190° C. for 2 hrs. Precipitate formed upon cooling. The solid precipitate was collected by filtration and washed with ether, then recrystallized from ethanol/tetrahydrofuran. Benzo[4,5]thieno[3,2-d]pyrimidin-4(3H)-one (9.9 g, 61% yield) was obtained.

Workup

customPrecipitate formed
temperatureupon cooling
filtrationThe solid precipitate was collected by filtration
washwashed with ether
customrecrystallized from ethanol/tetrahydrofuran

Sources & evidence

ORD record: ord-5ce9eae32b764ccd8eaac4fc24b98485
Source dataset: uspto-grants-2016_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09324949B2

Reaction notes

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