Phosphoric Acid → 2-Iodohexadecanoic acid

Temperature

110 °C

Procedure 3, Step A, for the preparation of methyl 16-=iodohexadecanoate (9), follows Takahashi et al, Appl. Radiat. Isot., 42, 801 (1991), incorporated herein by reference. To a mixture of phosphoric acid, (840 mg, 8.6 mmol) and phosphorus pentoxide (ca 450 mg), potassium iodide (868 mg, 5.2 mmol) and 16-hydroxyhexadecanoic acid (353 mg, 1.3 mmol), available from Aldrich Chemical Co., is added at room temperature and the mixture is heated at 110° C. for 3.5 h. The mixture is cooled to room temperature, and water (25 ml) and ether (120 ml) are added. The ether layer is separated, decolorized by shaking with 10% sodium thiosulfate solution (100 ml), washed with saturated NaCl aqueous solution (200 ml) , and evaporated to give crude 16-=iodohexadecanoic acid (38 mg). To a suspension of the sample in absolute MeOH (30 ml) thionyl chloride (6.5 ml) is added dropwise at 0° C. The mixture is stirred at 0° C. for 15 min and then refluxed for 30 min. After removal of the solvent, the residue is purified by preparative TLC (hexane/CH2Cl2 =7/3) to give 9 (26 mg). The procedure is performed on a 1-mole scale to provide enough material for Step C below.

1. addition, is added at room temperature
2. temperatureThe mixture is cooled to room temperature
3. customThe ether layer is separated
4. washwashed with saturated NaCl aqueous solution (200 ml)
5. customevaporated

ORD record

ord-605cdbbcd5f54a9588fb25700fd17226

Source dataset

uspto-grants-1995_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05455072