Chlorosulfonic acid → 7-Chlorosulfonyl-3,4-dihydro-1H-isoquinoline-2-carboxylic acid 2,2,2-trichloro-ethyl Ester

HRID 22822Notes

Reaction equation

HRID 22822 reaction equation
[Cl:1][C:2]([Cl:18])([Cl:17])[CH2:3][O:4][C:5]([N:7]1[CH2:16][CH2:15][C:14]2[C:9](=[CH:10][CH:11]=[CH:12][CH:13]=2)[CH2:8]1)=[O:6].[Cl:19][S:20](O)(=[O:22])=[O:21]>ClCCl>[Cl:18][C:2]([Cl:1])([Cl:17])[CH2:3][O:4][C:5]([N:7]1[CH2:16][CH2:15][C:14]2[C:9](=[CH:10][C:11]([S:20]([Cl:19])(=[O:22])=[O:21])=[CH:12][CH:13]=2)[CH2:8]1)=[O:6]

Participants

4

Reactant 2

HCID 24638Chlorosulfonic acidHCID 697439443,4-Dihydro-1H-isoquinoline-2-carboxylic acid 2,2,2-trichloro-ethyl Ester

Product 1

HCID 865914177-Chlorosulfonyl-3,4-dihydro-1H-isoquinoline-2-carboxylic acid 2,2,2-trichloro-ethyl EsterYield 83%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

Crude 3,4-dihydro-1H-isoquinoline-2-carboxylic acid 2,2,2-trichloro-ethyl ester (D6) (46 g, 150 mmol) was added dropwise over 40 minutes to chlorosulphonic acid (70 ml) cooled with an ice bath to maintain the temperature between 5 and 15° C. The mixture was then allowed to warm to room temperature, stirred for 16 hours, then poured onto crushed ice (500 ml) and dichloromethane (500 ml) added. This mixture was washed with water (3×250 ml), and brine (50 ml) then dried (sodium sulphate), filtered and evaporated to an orange oil which slowly crystallised on standing. This was recrystallised from ether-hexane to give the title compound (D7) as a white crystalline solid (64.5 g 83%); δH (CDCl3) ppm 3.03 (2H, app.t), 3.81-3.86 (2H, m), 4.74-4.85 (4H, m), 7.42 (1H, d), 7.82-7.88 (2H, m).

Workup

  1. temperaturecooled with an ice bath
  2. temperatureto maintain the temperature between 5 and 15° C
  3. additionpoured
  4. additionadded
  5. washThis mixture was washed with water (3×250 ml), and brine (50 ml)
  6. dry with materialthen dried (sodium sulphate)
  7. filtrationfiltered
  8. customevaporated to an orange oil which
  9. customslowly crystallised
  10. customThis was recrystallised from ether-hexane

Sources & evidence

ORD record
ord-c2e402aec3964993869571fc345c25c7
Source dataset
uspto-grants-2005_02
Patent number
US06849644B2

Reaction notes

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