Diazomethane → Methyl 11-hydroxy-4-oxotetradecanoate
Reaction equation
[OH:1][CH:2]([CH2:16][CH2:17][CH3:18])[CH2:3][CH2:4][CH2:5][CH2:6][CH2:7][CH2:8][C:9](=[O:15])[CH2:10][CH2:11][C:12]([OH:14])=[O:13].[N+](=[CH2:21])=[N-]>>[CH3:21][O:13][C:12](=[O:14])[CH2:11][CH2:10][C:9](=[O:15])[CH2:8][CH2:7][CH2:6][CH2:5][CH2:4][CH2:3][CH:2]([OH:1])[CH2:16][CH2:17][CH3:18]Participants
Procedure
In order to determine the stereochemistry at the 11-position, 1 was hydrolyzed first with base and then with acid to yield 11-hydroxy-4-oxo-tetradecanoic acid (8). The long chain fatty acid (8) was reacted with excess diazomethane to furnish 11-hydroxy-4-oxo-tetradecanoic acid methyl ester (9). Compound 9 was converted to the two Mosher esters 10 and 11 with (R)- and (S)-methoxyphenylacetic acid (MPA), using the EDCI/DMAP coupling conditions. (Seco, J. M.; Quinoa, E.; Riguera, R., Tetrahedron: Asymmetry 2001, 12, 2915-2925.) The resulting 11-MPA esters 10 and 11 were subjected to NMR analysis. The chemical shift differences ΔδRS were significant (Scheme 1), which made it possible to conclude that 1 had the (S)-configuration at C-11. The sugars were determined as D-glucose and D-fucose by hydrolysis and determination of the sign of rotation of the isolated carbohydrates. This conclusion was supported by MM2 calculations, which indicated that only the diastereomer with both D-sugars would give the relatively strong ROESY correlations between H-11 and H—F-1 and between H—F-2 and H-G-1 that were exhibited in the spectrum of 1.
Sources & evidence
- ORD record
- ord-1a9f1537de66439d814d6d79afdfeafb
- Source dataset
- uspto-grants-2009_07
- Patent number
- US07560536B2
Reaction notes
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