Acetic anhydride pyridine → HCID 67783663, compound

HRID 1654435Notes

Reaction equation

HRID 1654435 reaction equation
[C:1]([O:4][C:5](=[O:7])[CH3:6])(=[O:3])[CH3:2].[N:8]1[CH:13]=[CH:12]C=[CH:10][CH:9]=1.CS(C)=[O:16].[Cl-].[Na+].O>[Ag]=O.CO.[Pd]>[C:1]([OH:4])(=[O:3])[CH3:2].[C:9]([N:8]1[CH:13]=[CH:12][CH2:6][C:5]1=[O:7])(=[O:16])[CH3:10]

Participants

5

Reactant 2

HCID 22348678Acetic anhydride pyridineHCID 86608888HCID 86608888, compound

Product 1

HCID 67783663HCID 67783663, compound

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 86748092HCID 86748092, compoundCatalyst

Procedure

Methyl L-3-amino-(substituted phenyl)butyrate 16 is prepared from the appropriately substituted N-carbobenzoxy-L-alanine by Arndt-Eistert homologation, via the silver oxide-methanol rearrangement of the diazo ketone, followed by 10% Pd/C hydrogenolysis. The amino ester 16 is convened into the hydroxypyrrolone ester 17 by the method of Southwick, P. L., and R. T. Crouch, J. Am. Chem. Soc. 75:3413 (1953). The hydroxypyrrolone ester 17 is then treated with acetic anhydride-pyridine, with 4-N,N-dimethylaminopyridine as catalyst, for thirty minutes at room temperature, followed by hydrolysis-decarboxylation, using dimethyl sulfoxide-sodium chloride-water (50:28:1), at 135°-140° C. for 1.5 hours in a nitrogen atmosphere. The liberated hydroxyl is then reacetylated, and the N-acetyl pyrrolone acetate 18 is isolated by chromatography on silica, using 4:1 hexane-ethyl acetate followed by 3:2 chloroform-ethyl acetate. ##STR6##

Workup

  1. customfollowed by hydrolysis-decarboxylation

Sources & evidence

ORD record
ord-0a985f1a7884429fb72734dbb4ef66bb
Source dataset
uspto-grants-1995_04
Patent number
US05407658

Reaction notes

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