Piperonyl alcohol → 2(R)-[(3,4-methylenedioxybenzyl)-(4-methoxy-2,3,6-trimethylbenzene-sulfonyl)amino]-3(S)-(triethylsilyloxy)butyric acid 3,4-methylenedioxybenzyl ester

HRID 2298012Notes

Reaction equation

HRID 2298012 reaction equation
[CH2:1]1[O:39][C:38]2[CH:37]=[CH:36][C:5]([CH2:6][O:7][C:8](=[O:35])[C@H:9]([NH:20][S:21]([C:24]3[C:29]([CH3:30])=[CH:28][C:27]([O:31][CH3:32])=[C:26]([CH3:33])[C:25]=3[CH3:34])(=[O:23])=[O:22])[C@@H:10]([O:12][Si:13]([CH2:18][CH3:19])([CH2:16][CH3:17])[CH2:14][CH3:15])[CH3:11])=[CH:4][C:3]=2[O:2]1.[CH2:40]1[O:48][C:47]2[CH:46]=[CH:45][C:44]([CH2:49]O)=[CH:43][C:42]=2[O:41]1.C(P(CCCC)CCCC)CCC.N(C(N1CCCCC1)=O)=NC(N1CCCCC1)=O>C1C=CC=CC=1>[CH2:1]1[O:39][C:38]2[CH:37]=[CH:36][C:5]([CH2:6][O:7][C:8](=[O:35])[C@H:9]([N:20]([CH2:49][C:44]3[CH:45]=[CH:46][C:47]4[O:48][CH2:40][O:41][C:42]=4[CH:43]=3)[S:21]([C:24]3[C:29]([CH3:30])=[CH:28][C:27]([O:31][CH3:32])=[C:26]([CH3:33])[C:25]=3[CH3:34])(=[O:23])=[O:22])[C@@H:10]([O:12][Si:13]([CH2:16][CH3:17])([CH2:18][CH3:19])[CH2:14][CH3:15])[CH3:11])=[CH:4][C:3]=2[O:2]1

Participants

6

Reactant 4

HCID 10322Piperonyl alcoholHCID 13831TributylphosphineHCID 730421,1'-(Azodicarbonyl)dipiperidineHCID 865900262(R)-(4-methoxy-2,3,6-trimethylbenzenesulfonyl-amino)-3(S)-(triethylsilyloxy)butyric acid 3,4-methylenedioxybenzyl ester

Product 1

HCID 865900272(R)-[(3,4-methylenedioxybenzyl)-(4-methoxy-2,3,6-trimethylbenzene-sulfonyl)amino]-3(S)-(triethylsilyloxy)butyric acid 3,4-methylenedioxybenzyl esterYield 81.1%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

To a solution of 2(R)-(4-methoxy-2,3,6-trimethylbenzenesulfonyl-amino)-3(S)-(triethylsilyloxy)butyric acid 3,4-methylenedioxybenzyl ester (3.3 g, 5.7 mmol) in benzene (100 mL) at 0° C. was added 3,4-methylenedioxyphenyl methanol (1.3 g, 8.5 mmol), tri-n-butylphosphine (2.1 mL, 8.5 mmol), followed by 1,1′-[azodicarbonyl]dipiperidine (2.2 g, 8.5 mmol). The reaction mixture was allowed to warm to room temperature over 4 h. After 72 h, the reaction mixture was diluted with an equal volume of hexanes, cooled to 0° C. for 2 h and filtered. The residue was concentrated and chromatographed (300 g SiO2, 15% ethyl acetate-hexanes) to afford 2(R)-[(3,4-methylenedioxybenzyl)-(4-methoxy-2,3,6-trimethylbenzenesulfonyl)amino]-3(S)-(triethylsilyloxy)butyric acid 3,4-methylenedioxybenzyl ester (3.3 g) as a yellow oil.

Workup

  1. temperaturecooled to 0° C. for 2 h
  2. filtrationfiltered
  3. concentrationThe residue was concentrated
  4. customchromatographed (300 g SiO2, 15% ethyl acetate-hexanes)

Sources & evidence

ORD record
ord-dfee5cbc517c4ae5a7b22b6c2a6c8021
Source dataset
uspto-grants-2002_12
Patent number
US06492394B1

Reaction notes

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