Phenacyl bromide → 2-Azido-1-phenylethanone
Reaction equation
Br[CH2:2][C:3]([C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=1)=[O:4].[N-:11]=[N+:12]=[N-:13].[Na+]>>[N:11]([CH2:2][C:3]([C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=1)=[O:4])=[N+:12]=[N-:13]Participants
Procedure
The synthesis of 2,5-substituted thiazoles is described in Scheme 1. Reaction of alcohol R1—OH wherein R1 alkyl, aralkyl, heteroaryl, heterocyclo, or cycloalkyl with substituted 4-fluoroacetophenone 1 afforded the ether-acetophenone intermediate 2. Ether-acetophenone intermediate 2 was then converted to the corresponding bromo-acetophenone using Bu4NBr3, which, upon reaction with NaN3, provided the azido-acetophenone intermediate. Hydrogenation of the azido-acetophenone intermediate afforded amine 3, followed by coupling with orthogonally protected amino acid 4 or amino diol-carboxylic acid 5 gave amide 6. As a note, compound 4 was synthesized from (S)-2-(tert-butoxycarbonylamino)-3-hydroxy-2-methylpropanoic acid in three steps in overall 52-64% yield. A synthesis of (R)-3-(tert-butoxycarbonyl)-2,2,4-trimethyloxazolidine-4-carboxylic acid is described in Clemens, J. J.; Davis, M. D.; Lynch, K. R.; Macdonald, T. L. Bioorg. Med. Chem. Lett. 2005, 15, 3568-3572. Compound 5 was synthesized from 2-amino-2-(hydroxymethyl)propane-1,3-diol in five steps in overall 30% yield, also as described in Clemens, J. J.; Davis, M. D.; Lynch, K. R.; Macdonald, T. L. Bioorg. Med. Chem. Lett. 2005, 15, 3568-3572. Under conditions using Lawesson's reagent, amide 6 was converted to thiazole 7 in good yield. Removal of the protecting groups afforded the final alcohol 8, which upon reaction with diethyl chlorophosphate and subsequent deprotection with TMSBr gave the phosphate 9.
Sources & evidence
- ORD record
- ord-949edd8ddc4146e186eecc0e90e55495
- Source dataset
- uspto-grants-2010_07
- Patent number
- US07759370B2
Reaction notes
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