p-Toluenesulfonate → Glycine

HRID 1422171Notes

Reaction equation

HRID 1422171 reaction equation
S(C1C=CC(C)=CC=1)([O-])(=O)=O.[NH2:12][CH2:13][C:14]([O:16]CC1C=CC=CC=1)=[O:15].[C:24]1([P:30]([N:38]=[N+:39]=[N-:40])([C:32]2[CH:37]=[CH:36][CH:35]=[CH:34][CH:33]=2)=[O:31])[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1>CN(C=O)C>[NH2:12][CH2:13][C:14]([OH:16])=[O:15].[C:24]1([P:30]([N:38]=[N+:39]=[N-:40])([C:32]2[CH:37]=[CH:36][CH:35]=[CH:34][CH:33]=2)=[O:31])[CH:25]=[CH:26][CH:27]=[CH:28][CH:29]=1

Participants

6

Reactant 3

HCID 85570p-ToluenesulfonateHCID 199401P,P-Diphenylphosphinic azideHCID 409140Benzyl glycinate

Product 2

HCID 750GlycineHCID 199401P,P-Diphenylphosphinic azide

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

Coupling of the tosylate salt of benzyl glycinate with acid 9 proceeded smoothly to give the protected acyclic precursor 12, Scheme 5. Simultaneous hydrogenolysis of the Cbz and Bn protecting groups followed by cyclization with diphenylphosphoryl azide (DPPA) in dilute DMF solution afforded cyclic tripeptide methyl ester 13 in high yield.40In anticipation of future incorporation of amino acids beside Gly into the mimic, DPPA was chosen for cyclization because of the low propensity of acyl azides to racemize.41This cyclization has also been performed with Ala in the central position in 80% yield. ##STR6##

Workup

  1. customto give the protected acyclic precursor 12, Scheme 5

Sources & evidence

ORD record
ord-ee8357e80efc434ca1c39fda907bd2cb
Source dataset
uspto-grants-2000_06
Patent number
US06080838

Reaction notes

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