1,2,4,5-Tetrahydro-4-methyl-7,8-methylenedioxy-5-oxo-3-benzothiepin-2-carboxylic acid → (2S,4R)-(+)-1,2,4,5-tetrahydro-4-methyl-7,8-methylenedioxy-5-oxo-3-benzothiepin-2-carboxylic acid

HRID 618459Notes

Reaction equation

HRID 618459 reaction equation
[CH3:1][CH:2]1[S:8][CH:7]([C:9]([OH:11])=[O:10])[CH2:6][C:5]2[CH:12]=[C:13]3[O:18][CH2:17][O:16][C:14]3=[CH:15][C:4]=2[C:3]1=[O:19]>CO>[CH3:1][C@H:2]1[S:8][C@H:7]([C:9]([OH:11])=[O:10])[CH2:6][C:5]2[CH:12]=[C:13]3[O:18][CH2:17][O:16][C:14]3=[CH:15][C:4]=2[C:3]1=[O:19]

Participants

3

Reactant 1

HCID 159224451,2,4,5-Tetrahydro-4-methyl-7,8-methylenedioxy-5-oxo-3-benzothiepin-2-carboxylic acid

Product 1

HCID 10802686(2S,4R)-(+)-1,2,4,5-tetrahydro-4-methyl-7,8-methylenedioxy-5-oxo-3-benzothiepin-2-carboxylic acid

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

In 340 mL of methanol was suspended 20.00 g of a racemic mixture, 1,2,4,5-tetrahydro-4-methyl-7,8-methylenedioxy-5-oxo-3-benzothiepin-2-carboxylic acid (content 100%; trans compound 87.1%, cis compound 12.9%). To the suspension was added 11.01 g (1 equivalent) of (1S,2R)-norephedrine at room temperature (25° C.), followed by stirring for 1 hour. The resulting crystals were collected by filtration, washed with 80 mL of cold methanol, and dried over one night at room temperature under reduced pressure to afford 10.39 g of substantially pure (2S,4R)-1,2,4,5-tetrahydro-4-methyl-7,8-methylenedioxy-5-oxo-3-benzothiepin-2-carboxylic acid.(1S,2R)-norephedrine salt as colorless crystals [HPLC area percentage: (2R,4R):(2S,4S):(2S,4R):(2R,4S)=0%:0.7%:94.2%:4.0%].

Workup

  1. filtrationThe resulting crystals were collected by filtration
  2. washwashed with 80 mL of cold methanol
  3. customdried over one night at room temperature under reduced pressure

Sources & evidence

ORD record
ord-5a2e417802024898a147c1fd34a66c15
Source dataset
uspto-grants-1999_09
Patent number
US05952512

Reaction notes

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