Dimethylformamide → 2-BROMO-6-CHLOROTHIENO[2,3-B]PYRIDINE

HRID 354595Notes

Reaction equation

HRID 354595 reaction equation
C([NH:4][C:5]1[S:6][C:7]([Br:10])=[CH:8][CH:9]=1)(=O)C.[CH3:11]N(C)C=O.P(Cl)(Cl)(Cl)=O.[H][H].[Cl:23][CH2:24][C:25](Cl)(Cl)Cl>>[Br:10][C:7]1[S:6][C:5]2=[N:4][C:24]([Cl:23])=[CH:25][CH:11]=[C:9]2[CH:8]=1

Participants

6

Reactant 5

HCID 6228DimethylformamideHCID 124181,1,1,2-TetrachloroethaneHCID 24813Phosphorus oxychlorideHCID 4144312N-(5-bromothiophen-2-yl)acetamideHCID 178418361HCID 178418361, compound

Product 1

HCID 117157602-BROMO-6-CHLOROTHIENO[2,3-B]PYRIDINEYield 66%

Procedure

1 mole of 2-acetamido-5-bromothiophen was reacted with 1 mole dimethylformamide and 3 moles phosphorus oxychloride under reflux in tetrachloroethane for 3 hours at a temperature of 138° C. The compound of formula V in which R1 represents bromo, X represents chloro, and R2, R3 and R4 represent hydrogen was isolated in a yield of 66%. The remainder of the product was accounted for, mainly as unreacted starting material together with a small amount (ca 1%) of polymeric materials. The specified compound of formula V (2-bromo-6-chloro-thieno{2,3-b}-pyridine) was isolated from the crude product by chromatography on a short column of alumina using light petroleum spirit as eluant. The compound was recrystallised from ethanol and had a melting point of 116° C.

Workup

  1. customwas isolated in a yield of 66%

Sources & evidence

ORD record
ord-e0c3cc9e5b7f4440a78d2e312f63f375
Source dataset
uspto-grants-1983_03
Patent number
US04375544

Reaction notes

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