Water → HCID 13720668, compound

HRID 1701901Notes

Reaction equation

HRID 1701901 reaction equation
Cl[CH2:2][CH2:3][CH2:4][S:5][CH2:6][C:7]1[CH:12]=[N:11][CH:10]=[CH:9][N:8]=1.CC(C)([O-])C.[K+].CN(P(N(C)C)(N(C)C)=O)C.O>O1CCCC1.C(OCC)C>[N:8]1[CH:9]=[CH:10][N:11]=[CH:12][C:7]=1[CH:6]1[CH2:2][CH2:3][CH2:4][S:5]1

Participants

7

Reactant 4

HCID 962WaterHCID 12679HexamethylphosphoramideHCID 20505181HCID 20505181, compoundHCID 23665647Potassium tert-butoxide2×

Product 1

HCID 13720668HCID 13720668, compoundYield 40.3%

Reagents, catalysts & solvents 2

HCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent2×

Procedure

A solution of pyrazinylmethyl 3-chloropropyl sulphide (59 g) in anhydrous tetrahydrofuran (75 cc) is added dropwise, in the course of 15 minutes and whilst keeping the temperature below 30° C., to a solution of potassium tert.-butoxide (51 g) in a mixture of anhydrous hexamethylphosphorotriamide (75 cc) and anhydrous tetrahydrofuran (400 cc). After stirring for 30 minutes at the same temperature, potassium tert.-butoxide (10 g) is added and stirring is continued for 30 minutes. The reaction mixture is then run into a mixture of distilled water (800 cc) and diethyl ether (400 cc). After decantation, the aqueous phase is extracted twice with diethyl ether (300 cc in total). The organic extracts are combined, washed three times with distilled water (2400 cc in total), dried over anhydrous sodium sulphate and filtered and the filtrate is concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 35° C. The product obtained (30 g) is chromatographed on neutral silica gel (100 g) contained in a column of diameter 3 cm; the column is eluated with cyclohexane (750 cc), a cyclohexane/ethyl acetate mixture (90/10 by volume; 2500 cc) and ethyl acetate (500 cc), 250 cc fractions being collected. Fractions 4 to 15 are combined and concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 35° C. 2-Pyrazinyltetrahydrothiophen (19.5 g) is thus obtained in the form of a brown oil.

Workup

  1. customthe temperature below 30° C.
  2. additionis added
  3. extractionAfter decantation, the aqueous phase is extracted twice with diethyl ether (300 cc in total)
  4. washwashed three times with distilled water (2400 cc in total)
  5. dry with materialdried over anhydrous sodium sulphate
  6. filtrationfiltered
  7. concentrationthe filtrate is concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 35° C
  8. customThe product obtained (30 g)
  9. customis chromatographed on neutral silica gel (100 g)
  10. customa cyclohexane/ethyl acetate mixture (90/10 by volume; 2500 cc) and ethyl acetate (500 cc), 250 cc fractions being collected
  11. concentrationconcentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 35° C

Sources & evidence

ORD record
ord-905a1df5f33247f083128c336bde1133
Source dataset
uspto-grants-1983_04
Patent number
US04379154

Reaction notes

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