Methanol → 3,4-dihydro-6-nitro-2H-1-benzopyran-2-methanol

HRID 1906881Notes

Reaction equation

HRID 1906881 reaction equation
[N+:1]([C:4]1[CH:5]=[CH:6][C:7]2[O:12][CH:11]([C:13](O)=[O:14])[CH2:10][CH2:9][C:8]=2[CH:16]=1)([O-:3])=[O:2].CO>O1CCCC1>[N+:1]([C:4]1[CH:5]=[CH:6][C:7]2[O:12][CH:11]([CH2:13][OH:14])[CH2:10][CH2:9][C:8]=2[CH:16]=1)([O-:3])=[O:2]

Participants

4

Reactant 2

HCID 887MethanolHCID 22177067HCID 22177067, compound

Product 1

HCID 202110373,4-dihydro-6-nitro-2H-1-benzopyran-2-methanolYield 70%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

To a stirred mixture of 11.1 parts of 3,4-dihydro-6-nitro-2H-1-benzopyran-2-carboxylic acid and 63 parts of tetrahydrofuran were added dropwise, during a 30 minutes-period, 23.6 parts of a borane dimethyl sulfide complex solution 2M in tetrahydrofuran (slightly exothermic reaction: temp. rose to 27° C.). Upon completion, the whole was heated to reflux and stirring was continued for 2 hours at reflux temperature. The reaction mixture was decomposed by the dropwise addition of 8 parts of methanol at reflux temperature. After stirring and refluxing for 10 minutes, the solvents were distilled off and the residue was taken up in water. The solution was treated with concentrate hydrochloric acid and extracted with 1,1'-oxybisethane. The extract was washed with water, dried, filtered and evaporated. The solid residue was suspended in warm 2,2'-oxybispropane. The product was filtered off and dried, yielding 7.0 parts (70%) of 3,4-dihydro-6-nitro-2H-1-benzopyran-2-methanol; mp. 96.5° C. (intermediate 8).

Workup

  1. customslightly exothermic reaction
  2. customrose to 27° C.
  3. temperatureUpon completion, the whole was heated
  4. temperatureto reflux
  5. temperatureat reflux temperature
  6. temperatureat reflux temperature
  7. stirringAfter stirring
  8. temperaturerefluxing for 10 minutes
  9. distillationthe solvents were distilled off
  10. additionThe solution was treated with concentrate hydrochloric acid
  11. extractionextracted with 1,1'-oxybisethane
  12. washThe extract was washed with water
  13. customdried
  14. filtrationfiltered
  15. customevaporated
  16. filtrationThe product was filtered off
  17. customdried

Sources & evidence

ORD record
ord-e70e3b1fa7c247b1816ec2eb9eaaf8ea
Source dataset
uspto-grants-1987_03
Patent number
US04654362

Reaction notes

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