2,3-Dihydro-2,2,4,6,7-pentamethyl-5-benzofuransulfonyl chloride

White to gray powder

2, 2, 4, 6, 7-Pentamethyl-3H-benzofuran-5-sulfonyl chloride (38 mg, 0.13 mmol) was dissolved in DCM (2 mL) and 2-(2-chlorophenyl)ethanamine (46 mg, 0.3 mmol) was added followed by triethylamine (50 pL, 0.35 mmol). The reaction mixture was stirred for 1 hour at room temperature. Water (1 mL) was added. The layers were separated and the organic phase was concentrated. Purification by preparative HPLC (XBridge C18 19 x 50 mm; 0.1 % TFA(aq)/MeCN; 80:20 to 30:70) afforded the title compound as a white solid (6.9 mg, 10 %). MS ESI+ m/z 408 [M+H]+.2, 2, 4, 6, 7-Pentamethyl-3H-benzofuran-5-sulfonyl chloride (27 mg, 0.09 mmol) was dissolved in DCM (2 mL) and 2-(2-fluorophenyl)ethanamine (22 mg, 0.16 mmol) was added followed by triethylamine (50 pL, 0.35 mmol). The reaction mixture was stirred for 1 hour at room temperature. Water (1 mL) was added. The layers were separated and the organic phase was concentrated. Purification by preparative HPLC (XBridge C18 19 x 50 mm; 0.1 % TFA(aq)/MeCN; 80:20 to 30:70) afforded the title compound as a white solid (36.6 mg, 22 %). MS ESI+ m/z 392 [M+H]+.Under the ice water bath, Add water (3.17 L) to the 5 L three-neck bottle.Sodium hydroxide (152 g, 3.8 mol)And N-tert-butoxycarbonyl-L-arginine hydrochloride monohydrate(313 g, 0.95 mol), The mixture was stirred, and a mixed solution of Reference Example 4 Acetonitrile (8 mL)was added to a mixture of methyl 5-(5, 6, 7, 8-tetrahydro-1, 8-naphthyridin-2-yl)pentanoate (1.04 g), 2, 2, 4, 6, 7-pentamethyl-2, 3-dihydrobenzofuran-5-yl)sulfonyl chloride (1.33 g), and potassium carbonate (870 mg), followed by stirring for 8 hours at 70 C. By adding ethyl acetate (20 mL)and water (30 mL)thereto, the organic layer was fractionated. The organic layer was then washed with an aqueous saturated sodium hydrogen carbonate solution (30 mL)and dried over anhydrous sodium sulfate, and the solvent was distilled away under reduced pressure. The obtained reside was purified by silica gel column chromatography (hexane/ethyl acetate=85/15 to 65/35)and then recrystallized from IPA/hexane, thereby obtaining methyl 5-(8-((2, 2, 4, 6, 7-pentamethyl-2, 3-dihydrobenzofuran-5-yl)sulfonyl)-5, 6, 7, 8-tetrahydro-1, 8-naphthyridin-2-yl)pentanoate (1.18 g)as a white solid. LS/MS rt (min): 1.96 MS (ESI, m/z): 501.4[M+H]+ 1H-NMR (CDCl3)delta: 7.19 (1H, d, J=8.1 Hz), 6.56 (1H, d, J=8.1 Hz), 4.06-4.13 (2H, m), 3.64 (3H, s), 2.98 (2H, s), 2.75 (2H, t, J=7.2 Hz), 2.56 (3H, s), 2.50 (3H, s), 2.37 (2H, t, J=7.2 Hz), 2.16 (2H, t, J=7.5 Hz), 2.08 (3H, s), 2.01-2.05 (2H, m), 1.22-1.32 (2H, m)

reagent for introducing the PBF protection in arginine’s guanidine group

Molecular Weight:288.79
XLogP3:3.7
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:1
Exact Mass:288.0586933
Monoisotopic Mass:288.0586933
Topological Polar Surface Area:51.8
Heavy Atom Count:18
Complexity:426
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes