Solid-Phase Synthesis of a Tumor-Associated Sialyl-TN Antigen Glycopeptide with a Partial Sequence of the “Tandem Repeat” of the MUC-1 Mucin
✍ Scribed by Dipl.-Chem. Beate Liebe; Prof. Dr. Horst Kunz
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 489 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0044-8249
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✦ Synopsis
Although no evidence of a-haloalkylsamarium formation has been obtained, a reactive cc-iodoethyl species is undoubtedly generated in an optically active form. In conclusion, the reaction of 1,l-diiodoalkanes with samarium(l1) diiodide in the presence of chiral aldehydes produces a-haloaikyl building block in an enantioselective or diastereoselective manner. ['31 The further applications and limitations of the method are now under investigation.
Experimental Section
A mixture of aldehyde (0.5 mmol) and 1,l-diiodoalkane (1 .0 mmol) in T H F (2 mL) was added dropwise to a THF solution of SmI, (0.1 M, 2.0 mmol) under Ar atmosphere. After the obtained mixture had been stirred for 30-60 min, 1 M hydrochloric acid ( 5 mL) was added. T H F was removed by rotary evaporator. The resulting mixture was extracted with ether, and the combined organic layers subsequently washed with saturated NaHSO,, saturated NaHCO,, and brine. The obtained solution was dried over anhydrous Na,SO, and concentrated. The diastereomer ratio was determined by 'HNMR spectroscopy of the crude product. Purification by column chromatography (silica gel) gave the corresponding iodohydrin as a mixture of diastereomers.