Acetic Anhydride → HCID 178474728, compound

HRID 1032255Notes

Reaction equation

HRID 1032255 reaction equation
[NH2:1][CH2:2][CH2:3][CH2:4][C:5]1[NH:9][C:8]2[CH:10]=[CH:11][C:12]([C:14]3[CH:15]([CH3:21])[CH2:16][C:17](=[O:20])[NH:18][N:19]=3)=[CH:13][C:7]=2[N:6]=1.[C:22](OC(=O)C)(=[O:24])[CH3:23]>C(O)(=O)C>[C:22]([NH:1][CH2:2][CH2:3][CH2:4][C:5]1[NH:9][C:8]2[CH:10]=[CH:11][C:12]([C:14]3[CH:15]([CH3:21])[CH2:16][C:17](=[O:20])[NH:18][N:19]=3)=[CH:13][C:7]=2[N:6]=1)(=[O:24])[CH3:23]

Participants

4

Reactant 2

HCID 7918Acetic AnhydrideHCID 178429562HCID 178429562, compound

Product 1

HCID 178474728HCID 178474728, compoundYield 89%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

##STR59## 050 g (1.75 mmol) of 6-[2-(3-aminopropyl)-1H-benzimidazol-5-yl]-4,5-dihydro-5-methyl-3(2H)-pyridazinone are boiled with 0.34 ml (3.50 mmol) of acetic anhydride in 20 ml of glacial acetic acid for 45 minutes. The cooled solution is extensively concentrated by evaporation under vacuum and the residue is taken up with 10 ml of water. The resulting solution is adjusted to pH 9 with 10% ammonia. After concentration of this solution by evaporation to about one-third of its volume and cooling in an ice bath, a yellowish solid crystallizes, and this solid is suction filtered and then boiled up in 30 ml of acetonitrile. The solid obtained as residue is suction filtered, washed with 10 ml of acetonitrile and dried under vacuum. 0.51 g (89%) of colourless crystals melting at 244° to 246° C. are obtained.

Workup

  1. concentrationThe cooled solution is extensively concentrated by evaporation under vacuum
  2. customAfter concentration of this solution by evaporation to about one-third of its volume
  3. temperaturecooling in an ice bath
  4. customa yellowish solid crystallizes
  5. filtrationfiltered
  6. customThe solid obtained as residue
  7. filtrationfiltered
  8. washwashed with 10 ml of acetonitrile
  9. customdried under vacuum

Sources & evidence

ORD record
ord-b0369d98a96646138da4447176268a4e
Source dataset
uspto-grants-1990_09
Patent number
US04957920

Reaction notes

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