HCID 13282157, compound → HCID 70520957, compound

HRID 904811Notes

Reaction equation

HRID 904811 reaction equation
[CH3:1][N:2]1[C:6]([NH2:7])=[C:5]2[O:8][C:9]3[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=3[C:4]2=[N:3]1>C(OCC)(OCC)OCC>[CH2:5]([O:8][CH:9]=[N:7][C:6]1[N:2]([CH3:1])[N:3]=[C:4]2[C:10]3[CH:11]=[CH:12][CH:13]=[CH:14][C:9]=3[O:8][C:5]=12)[CH3:4]

Participants

3

Reactant 1

HCID 13282157HCID 13282157, compound

Product 1

HCID 70520957HCID 70520957, compoundYield 185%

Reagents, catalysts & solvents 1

HCID 31214Ethyl orthoformateSolvent

Procedure

A suspension of 2-methyl-2H-benzofuro[3,2-c]pyrazol-3-amine (3.8 g, 20 mmol, described in Example 6) in triethyl orthoformate (40 mL) was refluxed with stirring for 4 hr. The excess solvent was removed under vacuum and the residue was triturated with diethyl ether to give 4.5 g of N-ethoxymethylene-2-methyl-2H-benzofuro[3,2-c]pyrazol-3-amine, mp 120°-122° C., and NMR (CDCl3) δ1.4 (3H, t), 3.95 (3H, s), 4.4 (2H, q), 7.5 (4H, m) and 8.5 (1H, s). The latter compound was suspended in ethanol (100 mL) and sodium borohydride (1 g, 26 mmol) was added in portions. The mixture was stirred at room temperature for 1 hr and at reflux temperature for 0.5 hr. The solution was evaporated to dryness and the residue was taken up in ethyl acetate. The solution was washed with water, dried and evaporated to dryness. Chromatography on silica gel and elution with 2% EtOH--CH2Cl2 (v/v) gave 2.5 g of crystalline product, mp 150°-156° C. The latter product was triturated with diethyl ether to obtain the title compound: mp 154°-156° C.; IR (mineral oil) 3190, 1640, 1600 and 1547 cm-1 ; UV max (MeOH) 301 nm (ε=4820), 271 (14800), 251 (18900), 212 (20090) and shoulder 246; NMR (DMSO-d6) δ2.97 (3H, d), 3.68 (3H, s), 5.51 (1H, q) and 7.0-8.0 (4H, m).

Workup

  1. temperaturewas refluxed
  2. customThe excess solvent was removed under vacuum
  3. customthe residue was triturated with diethyl ether

Sources & evidence

ORD record
ord-2360ee99fa8d46d5a68638e5d08b7181
Source dataset
uspto-grants-1983_12
Patent number
US04420476

Reaction notes

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