Hydrochloric Acid → 4,4'-Dds dhp

HRID 439897

Reaction equation

HRID 439897 reaction equation
[CH:1]1[C:6]([NH2:7])=[CH:5][CH:4]=[C:3]([S:8]([C:11]2[CH:16]=[CH:15][C:14]([NH2:17])=[CH:13][CH:12]=2)(=[O:10])=[O:9])[CH:2]=1.[O:18]1[CH:23]=[CH:22][CH2:21][CH2:20][CH2:19]1.Cl>C1COCC1>[CH:15]1[C:14]([NH2:17])=[CH:13][CH:12]=[C:11]([S:8]([C:3]2[CH:4]=[CH:5][C:6]([NH2:7])=[CH:1][CH:2]=2)(=[O:10])=[O:9])[CH:16]=1.[CH2:22]1[CH2:23][O:18][CH:19]=[CH:20][CH2:21]1

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 2955DapsoneHCID 80803,4-dihydro-2H-pyran

Product 1

HCID 1317189254,4'-Dds dhpYield 196.1%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

Under nitrogen inside a resin kettle, placed 2.48 g of 4,4'-DDS (fw 248.3, 10.0 mmoles) and 40.0 mL of anhydrous THF. The diamine did not go into solution. While stirring with a high-torque mechanical stirrer, added 4.66 g of 6FDA (fw 444.2, 10.5 mmoles) and 10.0 mL more THF. Everything went into solution within 5 minutes. After 2 hours of stirring at room temperature added 16.0 g of dihydropyran and 0.2 g of pyr-HCl polymer. The reaction was then stirred for 60 hours at 35° C. under nitrogen with stirring. 1H NMR of crude reaction product shows 90+% conversion to the acetal ester. The catalyst was filtered off and the filtrate was added dropwise to a stirring blender containing 500 mL of hexane. The white precipitate was filtered, washed with hexane, dried under high vacuum to give 6.52 g of product. GPC analysis showed Mw =4730, Mn =2380, and Mw /Mn =1.99.

Workup

  1. stirringAfter 2 hours of stirring at room temperature
  2. stirringThe reaction was then stirred for 60 hours at 35° C. under nitrogen
  3. stirringwith stirring
  4. custom1H NMR of crude reaction product
  5. filtrationThe catalyst was filtered off
  6. additionthe filtrate was added dropwise to a stirring blender
  7. additioncontaining 500 mL of hexane
  8. filtrationThe white precipitate was filtered
  9. washwashed with hexane
  10. customdried under high vacuum

Sources & evidence

ORD record
ord-0362ce57238e40a3b4b44961c03c112a
Source dataset
uspto-grants-1996_05
Patent number
US05516875

Linked notes

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