Acetic Anhydride → 5,6-Dichloro-2-methyl[1,3]thiazolo[4,5-b]pyrazine

HRID 616556Notes

Reaction equation

HRID 616556 reaction equation
[NH2:1][C:2]1[C:7]([SH:8])=[N:6][C:5]([Cl:9])=[C:4]([Cl:10])[N:3]=1.[C:11](OC(=O)C)(=O)[CH3:12]>C1(C)C(C)=CC=CC=1>[Cl:10][C:4]1[N:3]=[C:2]2[N:1]=[C:11]([CH3:12])[S:8][C:7]2=[N:6][C:5]=1[Cl:9]

Participants

4

Reactant 2

HCID 7918Acetic Anhydride2×HCID 178508439HCID 178508439, compound

Product 1

HCID 203680305,6-Dichloro-2-methyl[1,3]thiazolo[4,5-b]pyrazineYield 64%

Reagents, catalysts & solvents 1

HCID 7237O-XyleneSolvent

Conditions

Temperature
110 °C

Procedure

A mixture of 9.8 g. (0.05 mol.) of 2-amino-5,6-dichloro-3-mercaptopyrazine and 5.1 g. (0.05 mol.) of acetic anhydride in 100 ml. of xylene was heated at 110° C. for 1 hour. The reaction mixture was cooled, another 5.1 g. of acetic anhydride was added and heating at 110° C. was continued for 15 hours. The reaction mixture was concentrated under reduced pressure to give a dark oil, which solidified under isopropanol-hexane while cooling in ice. The dark solid was purified by sublimation to give 7 g. (64% yield) of white solid, m.p. 58°-60° C.

Workup

  1. additionA mixture of 9.8 g
  2. temperatureThe reaction mixture was cooled
  3. concentrationThe reaction mixture was concentrated under reduced pressure
  4. customto give a dark oil, which
  5. temperaturewhile cooling in ice
  6. customThe dark solid was purified by sublimation
  7. customto give 7 g

Sources & evidence

ORD record
ord-c8dcb6634c304244962c8bcf676a540c
Source dataset
uspto-grants-1978_02
Patent number
US04075207

Reaction notes

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