Formaldehyde → 4,5,6,7-Tetrahydrothieno(3,2-c)pyridinium chloride

HRID 1866755Notes

Reaction equation

HRID 1866755 reaction equation
[S:1]1[CH:5]=[CH:4][CH:3]=[C:2]1[CH2:6][CH2:7][NH2:8].[Cl:9][CH:10](Cl)C.C=O>O>[ClH:9].[S:1]1[C:2]2[CH2:6][CH2:7][NH:8][CH2:10][C:3]=2[CH:4]=[CH:5]1

Participants

5

Reactant 3

HCID 712FormaldehydeHCID 63651,1-DichloroethaneHCID 116521Thiopheneethanamine

Product 1

HCID 101763424,5,6,7-Tetrahydrothieno(3,2-c)pyridinium chlorideYield 90%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Conditions

Temperature
30 °C

Procedure

100 gm. of 2-thienylethylamine was charged in a 1 liter reaction vessel equipped with a dean stark assembly for azeotropic removal of water. Dichloroethane (600 ml.) was added and the mixture stirred for 5 minutes. 26.4 gm. paraformaldehyde was added and the reaction mass was heated to reflux. Water formed in the reaction was continuously removed. After 4 hours the reaction mass was cooled to 30° C. and 133 ml. of 6.6N hydrochloric acid solution in dimethyl formamide was added. The reaction mass was heated to 70° C. for 4 hours. The reaction cooled to 15° C. and filtered under suction and washed with dichloroethane. The solid obtained was dried in oven at 50° C. 124 gm (90%) of 4,5,6,7-tetrahydrothieno(3,2-c)pyridine hydrochloride are obtained.

Workup

  1. temperaturethe reaction mass was heated to reflux
  2. customwas continuously removed
  3. additionof 6.6N hydrochloric acid solution in dimethyl formamide was added
  4. temperatureThe reaction mass was heated to 70° C. for 4 hours
  5. temperatureThe reaction cooled to 15° C.
  6. filtrationfiltered under suction
  7. washwashed with dichloroethane
  8. customThe solid obtained
  9. customwas dried in oven at 50° C

Sources & evidence

ORD record
ord-f0a0187f44ff4dfaae49a7524afe7fe0
Source dataset
uspto-grants-2009_12
Patent number
US07629465B2

Reaction notes

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