tert-Butanol → Tert-butyl thieno[2,3-b]pyrazin-6-ylcarbamate

HRID 1184921Notes

Reaction equation

[N:1]1[CH:6]=[CH:5][N:4]=[C:3]2[S:7][C:8](C(O)=O)=[CH:9][C:2]=12.C([N:15]([CH2:18]C)CC)C.C1C=CC(P(N=[N+]=[N-])(C2C=CC=CC=2)=[O:27])=CC=1.[C:37]([OH:41])([CH3:40])([CH3:39])[CH3:38]>>[N:1]1[CH:6]=[CH:5][N:4]=[C:3]2[S:7][C:8]([NH:15][C:18](=[O:27])[O:41][C:37]([CH3:40])([CH3:39])[CH3:38])=[CH:9][C:2]=12

Participants

Reactant 4

HCID 6386tert-Butanol

HCID 8471Triethylamine

HCID 199401P,P-Diphenylphosphinic azide

HCID 7164578Thieno[2,3-b]pyrazine-6-carboxylic acid

Product 1

HCID 58873972Tert-butyl thieno[2,3-b]pyrazin-6-ylcarbamateYield 92%

Conditions

Temperature: 85 °C

Procedure

To a solution of thieno[2,3-b]pyrazine-6-carboxylic acid (5.55 mmol, 1 g) and triethylamine (16.65 mmol, 2.321 mL) in t-butanol (15 mL) at 70° C., DPPA (6.10 mmol, 1.320 mL) was added. The dark brown solution was stirred overnight at 85° C. The reaction mixture was evaporated to dryness. Purification by chromatography (0-30% ethyl acetate in heptane) gave tert-butyl thieno[2,3-b]pyrazin-6-ylcarbamate 105 (1.28 g, 92%). NMR (400 MHz, CDCl3) 1.57 (s, 9H), 6.77 (s, 1H), 7.42 (br s, 1H), 8.30 (d, J=2.7 Hz, 1H), 8.48 (d, J=2.7 Hz, 1H).

Workup

customThe reaction mixture was evaporated to dryness
customPurification by chromatography (0-30% ethyl acetate in heptane)

Sources & evidence

ORD record: ord-af11309b8d6e411189991e6ae7a48950
Source dataset: uspto-grants-2014_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08669256B2

Reaction notes

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