Nitric Acid → 5,6-Dihydro-6-hydroxy-5,5-dimethyl-2-nitro-7-(4-nitrobenzamido)-7H-thieno[3,2-b]pyran

HRID 1086640Notes

Reaction equation

HRID 1086640 reaction equation
[OH:1][CH:2]1[C:7]([CH3:9])([CH3:8])[O:6][C:5]2[CH:10]=[CH:11][S:12][C:4]=2[CH:3]1[NH:13][C:14](=[O:24])[C:15]1[CH:20]=[CH:19][C:18]([N+:21]([O-:23])=[O:22])=[CH:17][CH:16]=1.[N+:25]([O-])([OH:27])=[O:26].[K+].[Br-]>C(O)(=O)C>[OH:1][CH:2]1[C:7]([CH3:8])([CH3:9])[O:6][C:5]2[CH:10]=[C:11]([N+:25]([O-:27])=[O:26])[S:12][C:4]=2[CH:3]1[NH:13][C:14](=[O:24])[C:15]1[CH:20]=[CH:19][C:18]([N+:21]([O-:23])=[O:22])=[CH:17][CH:16]=1

Participants

5

Reactant 3

HCID 944Nitric AcidHCID 253877Potassium BromideHCID 149864905,6-Dihydro-6-hydroxy-5,5-dimethyl-7-(4-nitrobenzamido)-7H-thieno[3,2-b]pyran

Product 1

HCID 149865005,6-Dihydro-6-hydroxy-5,5-dimethyl-2-nitro-7-(4-nitrobenzamido)-7H-thieno[3,2-b]pyran

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

5,6-Dihydro-6-hydroxy-5,5-dimethyl-7-(4-nitrobenzamido)-7H-thieno[3,2-b]pyran (1.5 g, 4.30 mmol) was treated with 90% nitric acid (2.5 mL, 53.5 mmol) in acetic acid (25 mL) and stirred at 15°-20° C. for 0.5 h. The resultant solution was poured into ice water 100 mL and extracted with 10% isopropanol in dichloromethane. The dichloromethane solution was washed with saturated aqueous sodium bicarbonate and dried over magnesium sulfate. The solvent was evaporated in vacuo and the residue was purified by medium pressure chromatography using 2% methanol in dichloromethane as the eluant, to give the product, 0.489 g (29%), as a yellow solid: mp 221°-225° C. dec; IR (KBr): 3345, 1647 and 1602 cm-1 ; MS: m/z 394 (MH+); 1H NMR (DMSO-d6): δ1.26(s, 3H), 1.45(s, 3H), 3.90(dd, J=8.8 Hz and J=5.9 Hz, 1H, simplifies to d, J=8.8 Hz with D2O), 4.98(dd, J=7.6 Hz and J=8.8 Hz, 1H, simplifies to d, J=8.8 Hz with D2O), 6.01(d, J=5.9 Hz, 1H exchanges with D2O), 7.75(s, 1H), 8.14(d, J=8.8 Hz, 2H) 8.37(d, J=8.8 Hz, 2H) and 9.38(d, J=7.6 Hz, 1H, exchanges with D2O).

Workup

  1. extractionextracted with 10% isopropanol in dichloromethane
  2. washThe dichloromethane solution was washed with saturated aqueous sodium bicarbonate
  3. dry with materialdried over magnesium sulfate
  4. customThe solvent was evaporated in vacuo
  5. customthe residue was purified by medium pressure chromatography
  6. customto give the product, 0.489 g (29%)

Sources & evidence

ORD record
ord-86f2c46b10a54fbdbee81e0c1862041c
Source dataset
uspto-grants-1991_07
Patent number
US05030736

Reaction notes

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