Formamide → 5,6-Dihydro-3H-pyrano[4',3':4,5]thieno[2,3-D]pyrimidin-4(8H)-one

Reaction equation

C([O:3][C:4]([C:6]1[C:14]2[CH2:13][CH2:12][O:11][CH2:10][C:9]=2[S:8][C:7]=1[NH2:15])=O)C.[CH:16]([NH2:18])=O>>[N:15]1[C:7]2[S:8][C:9]3[CH2:10][O:11][CH2:12][CH2:13][C:14]=3[C:6]=2[C:4](=[O:3])[NH:18][CH:16]=1

Participants

Reactant 2

HCID 713Formamide

HCID 10987982Ethyl 2-amino-5,7-dihydro-4H-thieno[2,3-c]pyran-3-carboxylate

Product 1

HCID 4032245,6-Dihydro-3H-pyrano[4',3':4,5]thieno[2,3-D]pyrimidin-4(8H)-oneYield 42%

Procedure

2-Amino-4,5-dihydro-7H-thieno[2,3-c]pyran-3-carboxylic acid ethyl ester (26 g, 0.114 mol) was dissolved in formamide (200 ml) and the resulting mixture was heated at reflux temperature for 1.5 h. After cooling to room temperature the precipitate was filtered off, washed with water (2×80 ml) and dried in vacuo at 50° C. for 18 h which afforded 10.0 g (42%) of 5,6-dihydro-8H-pyrano[4′,3′:4,5]thieno[2,3-d]pyrimidin-4-one as a solid.

Workup

temperaturethe resulting mixture was heated
temperatureat reflux temperature for 1.5 h
filtrationwas filtered off
washwashed with water (2×80 ml)
customdried in vacuo at 50° C. for 18 h which

Sources & evidence

ORD record: ord-00b6f29b7b8141d19b643869d16f4265
Source dataset: uspto-grants-2005_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06951878B2

Reaction notes

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