* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
N-Boc-1,4-diaminobutane [MONOHYDROCHLORIDE] (430 mg, 2.25 mmol, 1.0 eq) was dissolved in water (15 mL) and [MECN] [(10ML).] Sodium carbonate (120 mg, 1.12 mmol, 0.5 eq) was added as a solution in water (5 mL), followed by [BOC-LYS] [(BOC)] OSu (1.0 [G,] 2.25 mmol, 1.0 eq) as a solution in [MECN] (20 mL). The reaction was then left to stir overnight. The reaction mixture was concentrated and water added before being extracted with DCM (3 x 50 mL). The combined organic layers were then washed with 0.01 N HCI (2 x 50 mL), brine, dried over [MGS04] and concentrated. Purification by normal phase chromatography yielded the product (white foam, 1.0 g, 86%).
4-(tert-butyloxycarbonylamino)butylamine hydrochloride The 4-(tert-butyloxycarbonylamino)butylamine hydrochloride was obtained from 4-aminobutan-1-ol in accordance with procedures described in literature (Mattingly, P. G., Synthesis, 1990, 1990, 366-368). m.p. 156-158 C.
carboxymethyl-3b-acetoxy-urs-12-en-28-oate[ No CAS ]
[ 33545-98-1 ]
3β-acetoxyurs-12-ene-28-oic acid[1-(4-N-Boc-aminobutylamino)-1-oxo]ethyl ester[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
71%
With dmap; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; In dichloromethane; at 0 - 20℃; for 3.08333h;
General procedure: To a stirred solution of OA-3 (250.12 mg, 0.45 mmol), NBoc-ethylenediamine (86.29 mg, 0.54 mmol) and DMAP(65.85 mg, 0.54 mmol) in anhydrous methylene chloridewas added EDCI (344.23 mg, 1.80 mmol) which dissolvedin anhydrous methylene chloride at 0 C. The reactionmixture was stirred for 5 min, and then at room temperaturefor 3 h. The reaction mixture was extracted with methylenechloride and water, washing to neutral with saturated NaClsolution. The organic layer was dried over anhydrousmagnesium sulfate. Filtration and evaporation of solvent atreduced pressure gave light yellow solid, which was purifiedby silica gel chromatography with a gradient elution of ethyl acetate-petroleum ether (1:2, v/v) to yield a whitesolid (244.02 mg, 78%),
2-(3β-acetoxyolean-12-ene-28-acetoxy)acetic acid[ No CAS ]
[ 33545-98-1 ]
3β-acetoxyolean-12-ene-28-oic acid[1-(4-N-Boc-aminobutylamino)-1-oxo]ethyl ester[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
85%
With dmap; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; In dichloromethane; at 0 - 20℃; for 3.08333h;
General procedure: To a stirred solution of OA-3 (250.12 mg, 0.45 mmol), NBoc-ethylenediamine (86.29 mg, 0.54 mmol) and DMAP(65.85 mg, 0.54 mmol) in anhydrous methylene chloridewas added EDCI (344.23 mg, 1.80 mmol) which dissolvedin anhydrous methylene chloride at 0 C. The reactionmixture was stirred for 5 min, and then at room temperaturefor 3 h. The reaction mixture was extracted with methylenechloride and water, washing to neutral with saturated NaClsolution. The organic layer was dried over anhydrousmagnesium sulfate. Filtration and evaporation of solvent atreduced pressure gave light yellow solid, which was purifiedby silica gel chromatography with a gradient elution of ethyl acetate-petroleum ether (1:2, v/v) to yield a whitesolid (244.02 mg, 78%),
With triethylamine; In tetrahydrofuran; at 0 - 20℃;Inert atmosphere;
FIG. 5 illustrates the side chain, BOCNHCH2CH2CH2CH2NHCBz. One skilled in the art will appreciate that BOCNHCH2CH2CH2CH2NHCBz is merely an illustrative side chain, and that other side chains may be synthesized in accordance with the present disclosure. Triethylamine (about 16 mL, about 116 mmol, 2.5 eq.) was added to a stirring slurry of BOCNHCH2CH2CH2CH2CH2NH3Cl (about 10.4 g, about 46 mmol, 1.0 eq.) in tetrahydrofuran (THF) (about 92 mL, about 0.5 M), contained in a RBF (e.g., a 250 mL RBF). The resulting slurry was chilled in an ice bath and N-(benzyloxycarbonyloxy)succinimide (CBz-OSu) (about 11.5 g, about 46 mmol, 1.0 eq.) was then added in portions. The reaction mixture was then stirred under Ar at about 0 C. for about 5 minutes, warmed to rt, then stirred at rt overnight. The solvent was then removed from the reaction mixture via rotary evaporation. H2O (about 100 mL) was added and the mixture was extracted with EtOAc (about 1502 mL, 3×50 mL), washed with aqueous 0.1 M HCl (about 100 mL) and brine (about 100 mL), and dried over Na2SO4. The solution was filtered and concentrated to dryness yielding a white colored solid produce (BOCNHCH2CH2CH2CH2NHCBz). The product was spectroscopically pure after drying overnight under high vacuum. The product weighed about 14.2 g (about 95% yield).