Acetic Anhydride → Ethyl 5-acetylamino-4,5,6,7-tetrahydro-3-methylthio-4-oxobenzo[c]thiophene-1-carboxylate

HRID 2296800Notes

Reaction equation

HRID 2296800 reaction equation
[N:1]([CH:4]1[CH2:19][CH2:18][C:7]2=[C:8]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[S:9][C:10]([S:11][CH3:12])=[C:6]2[C:5]1=[O:20])=[N+]=[N-].[C:21](OC(=O)C)(=[O:23])[CH3:22]>C(O)(=O)C>[C:21]([NH:1][CH:4]1[CH2:19][CH2:18][C:7]2=[C:8]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[S:9][C:10]([S:11][CH3:12])=[C:6]2[C:5]1=[O:20])(=[O:23])[CH3:22]

Participants

4

Reactant 2

HCID 7918Acetic AnhydrideHCID 18388306Ethyl 5-azido-4,5,6,7-tetrahydro-3-methylthio-4-oxobenzo(c]thiophene-1-carboxylate

Product 1

HCID 12043499Ethyl 5-acetylamino-4,5,6,7-tetrahydro-3-methylthio-4-oxobenzo[c]thiophene-1-carboxylateYield 73.8%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A mixture of ethyl 5-azido-4,5,6,7-tetrahydro-3-methylthio-4-oxobenzo[c]thiophene-1-carboxylate (3.62 g), palludium-carbon (5%, 50% wet, 4.0 g), acetic acid (70 ml) and acetic anhydride (35 ml) was subjected to a catalytic reduction reaction at room temperature under 1 atm. The insoluble substances were filtered off; the filtrate was concentrated under reduced pressure; the residue was dissolved in ethyl acetate-tetrahydrofuran (3;1, v/v). This solution was washed with water, a saturated aqueous solution of sodium hydrogen carbonate and water in that order, and dried (MgSO4), after which the solvent was distilled off to yield ethyl 5-acetylamino-4,5,6,7-tetrahydro-3-methylthio-4-oxobenzo[c]thiophene-1-carboxylate (2.81 g, 73.8%), which was then recrystallized from chloroform-ethanol. Colorless needles. Melting point 215-216° C.

Workup

  1. customwas subjected to a catalytic reduction reaction at room temperature under 1 atm
  2. filtrationThe insoluble substances were filtered off
  3. concentrationthe filtrate was concentrated under reduced pressure
  4. dissolutionthe residue was dissolved in ethyl acetate-tetrahydrofuran (3;1
  5. washThis solution was washed with water
  6. dry with materiala saturated aqueous solution of sodium hydrogen carbonate and water in that order, and dried (MgSO4)
  7. distillationafter which the solvent was distilled off

Sources & evidence

ORD record
ord-ca67456e7ffe48269c12bed9c4e02298
Source dataset
uspto-grants-2002_12
Patent number
US06489351B1

Reaction notes

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