4-Chlorobenzonitrile → Ethyl 5-(4-chlorophenyl)-1,2,4-thiadiazole-3-carboxylate

HRID 1764057Notes

Reaction equation

HRID 1764057 reaction equation
O=C1[S:6][N:5]=[C:4]([C:7]([O:9][CH2:10][CH3:11])=[O:8])O1.[Cl:12][C:13]1[CH:20]=[CH:19][C:16]([C:17]#[N:18])=[CH:15][CH:14]=1>>[Cl:12][C:13]1[CH:20]=[CH:19][C:16]([C:17]2[S:6][N:5]=[C:4]([C:7]([O:9][CH2:10][CH3:11])=[O:8])[N:18]=2)=[CH:15][CH:14]=1

Participants

3

Reactant 2

HCID 121634-ChlorobenzonitrileHCID 12351252ethyl 2-oxo-2H-1,3,4-oxathiazole-5-carboxylate

Product 1

HCID 12351255Ethyl 5-(4-chlorophenyl)-1,2,4-thiadiazole-3-carboxylateYield 61.4%

Procedure

A sample of p-chlorobenzonitrile was distilled and then crystallized twice from methylcyclohexane to remove impurities that interfered in the following reaction. A solution of 8.76 g (0.050 mol) of ethyl 2-oxo-1,3,4-oxathiazole-5-carboxylate and 68.8 g (0.50 mol, 10 equiv.) of purified p-chlorobenzonitrile was held at 190° C for 72 hours. The solution, which contained the product in 69% yield, was concentrated under vacuum to 150° C (about 2 torr). The residue was crystallized from heptane (charcoal) to give 8.25 g (61%) of gold crystals, mp 98°-99.5° C. A small sample was crystallized twice from heptane (charcoal) to give a white solid, mp 98°-99.5° C.

Workup

  1. distillationA sample of p-chlorobenzonitrile was distilled
  2. customcrystallized twice from methylcyclohexane
  3. customto remove impurities that
  4. custominterfered in the following reaction
  5. concentrationwas concentrated under vacuum to 150° C (about 2 torr)
  6. customThe residue was crystallized from heptane (charcoal)

Sources & evidence

ORD record
ord-115c6e2106474dd6bc9a6f82b00ea264
Source dataset
uspto-grants-1978_09
Patent number
US04115095

Reaction notes

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