Improved synthesis of (5Z)-7-(3-endo-{(benzenesulfonamido)-bicyclo[2.2.1]heptyl}hept-5-enoic acid (S-145) derivatives and their iodine-125-labeled radioligands for the study of thromboxane A2 receptor
✍ Scribed by Wai Ming Kan; Hsin-Hsiung Tai
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 567 KB
- Volume
- 65
- Category
- Article
- ISSN
- 0009-3084
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✦ Synopsis
An improved synthetic scheme for (5Z)-7-[3-endo-[(benzenesulfonamido)-bicyclo[2.2.1]heptyl I-hept-5-enoic acid (S145) and its analogs has been designed. The procedure involves direct sulfonylation of 2-allyl-3-aminobicyclo[2.2. l]heptane intermediate followed by ozonolysis and addition of a C5 carboxyl unit. The yield of the final product was significantly improved. (5Z)-7-{ 3-endo-[(4iodobenzensulfonamido)-bicyclo 12.2.1]heptyllhept-5-enoic acid (HS-145) and (5Z)-7-13-endo-(4-hydroxy-benzensulfonamido)bicyclo [2.2. llheptyllhept-5-enoic acid (HS-145) were synthesized directly without any protection and deprotection steps, l ]25I-7-13-endo-[(4-iodobenzensulfonamido)-bicyclo[2.2, i]heptyl}hept-5-enoic acid ([ 125I]HS-145) was prepared from IS-145 through an organotin intermediate and [ 125I]sodium iodide with high specific radioactivity and good recovery of radioactivity. 125I-7-[3endo-l(4-hydroxy 3-iodo-benzensulfonamido)-bicyclol2.2. l l-heptyllhept-5-enoic acid ([]25I]HS-145) was prepared by direct iodination with sodium iodide using a modified chloramine-T method. Both [125I]HS-145 and [125I]HS-145 were found to be valuable radioligands for studying thromboxane A 2 (TXA2) receptor.