2-(tert-Butoxycarbonyl)-5,7-dichloro-1,2,3,4-tetrahydroisoquinoline-6-carboxylic Acid is a carboxylic acid derivative of tetrahydroisoquinoline with a Boc group and two chlorine atoms attached to the tetrahydroisoquinoline ring. It may exhibit various biological activities, such as anticancer, anti-inflammatory, and anticonvulsant properties, depending on the nature and position of the substituents.
2-(tert-Butoxycarbonyl)-5,7-dichloro-1,2,3,4-tetrahydroisoquinoline-6-carboxylic Acid is a reagent in the preparation of N-benzofuranylcarbonyl dichlorotetrahydroisoquinolinylcarbonylmethylsulfonyl L-phenylalanine as LFA-1 inhibitor and polymorph thereof for the treatment of LFA -1 mediated diseases.

Boc-protection was used for the ring nitrogen in the intermediates 21 and 22.Compound 5 was deprotected with HC1 in dioxane to produce compound 23 in better than 97%yield. Boc-protection was introduced, using di-tert-butyl dicarbonate (1 .1 equivalent), and compound 21 was obtained in better than 95% yield. Compound 10 was coupled with compound 21 to obtain compound 22, using HATU and triethylamine in DMF. The product, compound 22, was obtained in quantitative yield, and greater than 90% purity. Deprotection with HC1 yielded the compound of Formula 12 in 97.4% yield.
[1] Patent: WO2005/44817, 2005, A1. Location in patent: Page/Page column 77-79
[2] Patent: WO2014/18748, 2014, A1. Location in patent: Paragraph 00118; 00119
[3] Bioorganic and Medicinal Chemistry Letters, 2010, vol. 20, # 17, p. 5269 - 5273