Methyl propiolate → ethyl 2-oxo-2H-pyrimido[2,1-b]benzothiazole-8-acetate

HRID 34530

Reaction equation

HRID 34530 reaction equation
[NH2:1][C:2]1[S:3][C:4]2[CH:10]=[C:9]([CH2:11][C:12]([O:14][CH2:15][CH3:16])=[O:13])[CH:8]=[CH:7][C:5]=2[N:6]=1.[C:17](OC)(=[O:20])[C:18]#[CH:19]>C(O)C>[O:20]=[C:17]1[CH:18]=[CH:19][N:6]2[C:2]([S:3][C:4]3[CH:10]=[C:9]([CH2:11][C:12]([O:14][CH2:15][CH3:16])=[O:13])[CH:8]=[CH:7][C:5]=32)=[N:1]1

Participants

4

Reactant 2

HCID 13536Methyl propiolateHCID 821202(2-Amino-benzothiazol-6-yl)-acetic acid ethyl ester

Product 1

HCID 13477942ethyl 2-oxo-2H-pyrimido[2,1-b]benzothiazole-8-acetateYield 48%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A stirred mixture of 5 g of ethyl 2-aminobenzothiazole-6-acetate [prepared according to Sawhney et al., Ind J. Chem., Vol. 16B p. 605 (1978)], 1.95 g of methyl propiolate and 30 ml of ethanol was heated under reflux for 2 hours and the mixture was allowed to cool. The crude product was collected and then recrystallized from n-butyl alcohol to obtain 2.88 g of ethyl 2-oxo-2H-pyrimido[2,1-b]benzothiazole-8-acetate as yellow needles (48% yield).

Workup

  1. temperaturewas heated
  2. temperatureunder reflux for 2 hours
  3. temperatureto cool
  4. customThe crude product was collected
  5. customrecrystallized from n-butyl alcohol

Sources & evidence

ORD record
ord-a1b92139392b4104a22c17f1bae70340
Source dataset
uspto-grants-1988_08
Patent number
US04762840

Linked notes

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