7-Methoxy-1-oxo-1H-pyrimido[6,1-b]benzthiazole-4-carboxylic acid → HCID 178487336, compound

Participants

Reaction Conditions

Reaction Steps

5.52 g. 7-Methoxy-1-oxo-1H-pyrimido[6,1-b]benzthiazole-4-carboxylic acid (prepared according to Example 1) in 150 ml. dimethylformamide are mixed with 7.14 g. N,N'-carbonyldiimidazole. The reaction mixture is subsequently stirred for 90 minutes at 100° C. and for 1 hour at ambient temperature, then mixed with 2.26 g. 5-aminotetrazole monohydrate and again heated for 3 hours at 100° C. The solvent is substantially removed in vacuo and the residue stirred with water. The precipitate consists of 5.2 g. N-(5-tetrazolyl)-7-methoxy-1-oxo-1H-pyrimido[6,1-b]benzthiazole-4-carboxamide (75.7% of theory); m.p. 234°-235° C. (recrystallized from nitromethane).

Provenance & Evidence