Formamide → 1,2-dihydropyrazolo[4,3-g]quinazolin-5-one

HRID 27769Notes

Reaction equation

HRID 27769 reaction equation
[NH2:1][C:2]1[CH:10]=[C:9]2[C:5]([CH:6]=[N:7][NH:8]2)=[CH:4][C:3]=1[C:11]([OH:13])=O.[CH:14]([NH2:16])=O>>[NH:8]1[C:9]2[C:5]([CH:4]=[C:3]3[C:2]([CH:10]=2)=[N:1][CH:14]=[N:16][C:11]3=[O:13])=[CH:6][NH:7]1

Participants

3

Reactant 2

HCID 713FormamideHCID 126378406-amino-1H-indazole-5-carboxylic acid2×

Product 1

HCID 1785179461,2-dihydropyrazolo[4,3-g]quinazolin-5-one

Procedure

450 mg (2.5 m-mol) of 6-amino-indazole-5-carboxylic acid (formula 20, prepared according to Example XIII) in 3 ml of formamide were heat-melted and kept at a temperature of 140° during a period of 4.5 hours and then at a temperature of 180° during another period of 1.5 hours. The mass obtained was cooled to room temperature. The product was filtered under suction, washed well with water until the filtrate became clear, and then washed with a small amount of ethanol. The target product (formula 3) was recovered in an amount of 167 mg (36%) in the form of a greyish-brown, finely crystalline material, m.p. 330°. The product was uniform as evidenced by chromatography; pmr (DMSO-d6): δ 7.78, 8.10, 8.44, 8.76 (4 broad s, 4, H3, H4, H7, H9), 11.92, 13.36 (2 with D2O exchangeable broad m, 2, N1H, N6H), (DMSO-d 6 /D2O): δ 7.83, 8.10, 8.45, 8.78 (4 sharp s, 4, H3, H4, H7, H9); ms (70 eV): m/e 186 (100%, M+).

Workup

  1. waitat a temperature of 180° during another period of 1.5 hours
  2. customThe mass obtained
  3. filtrationThe product was filtered under suction
  4. washwashed well with water until the filtrate
  5. washwashed with a small amount of ethanol
  6. customThe target product (formula 3) was recovered in an amount of 167 mg (36%) in the form of a greyish-brown, finely crystalline material, m.p. 330°

Sources & evidence

ORD record
ord-e271d34c4fff4a18b2545544ce4b1a9d
Source dataset
uspto-grants-1980_09
Patent number
US04223143

Reaction notes

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