| 100% |
With guanidinium monohydrochloride In ethanol at 35 - 40℃; for 0.0166667h; |
2.1. General procedure for N-tert-butoxycarbonylation of amines:
General procedure: Amine (1 mmol) was added to a magnetically stirred solution of guanidine hydrochloride (15 mol%) and di-tert-butyl dicarbonate (1.2 mmol) in EtOH (1 mL), at 35-40°C and stirred for appropriate time (Table 1). After completion of the reaction (followed by TLC or GC), EtOH was evaporated under vacuum and the residue either was washed with water to remove the catalyst or was dissolved in CH2Cl2 (or EtOAc) and filtered off to separate out the catalyst. Evaporation of the organic solvent (if used in work up) gives almost a pure product. In the cases of using an excess (Boc)2O the product was washed with petroleum ether or hexane to recover the residual (Boc)2O. If necessary, the product was further purified either by crystallization (hexane and dichloromethane, or diethyl ether and petroleum ether) or silica gel column chromatography using EtOAc-hexane (1: 6) as eluent. |
| 100% |
With amberlyst-15 In ethanol at 20℃; for 0.0166667h; chemoselective reaction; |
|
| 99% |
With amberlyst-15 at 20℃; for 0.0333333h; Neat (no solvent); |
|
| 99% |
With triethylamine In dichloromethane at 0 - 20℃; for 16h; |
|
| 99% |
With iron(III) trifluoromethanesulfonate In neat (no solvent) at 20℃; for 0.0333333h; Green chemistry; |
N-Boc protection of amines
General procedure: Fe(OTf)3 (1 mol%) was added to a magnetically stirred mixture of anamine (1 mmol) and Boc2O (1 mmol) at room temperature. The mixturewas stirred until completion of the reaction (TLC), then diluted withEtOAc and washed with water. The organic layer was dried overanhydrous MgSO4, then the solvent was distillated off under vacuum toyield the highly pure N-Boc derivatives |
| 99% |
With 1-butyl-3-methylimidazolium trifluoroacetate In neat (no solvent) at 20℃; for 0.166667h; |
|
| 99% |
In lithium hydroxide monohydrate at 80℃; for 0.0833333h; Microwave irradiation; Green chemistry; chemoselective reaction; |
|
| 99% |
With 8Na(1+)*12C4H10NO(1-)*2HO(1-)*2Nd(3+) In neat (no solvent) at 20℃; for 0.0333333h; Inert atmosphere; Schlenk technique; Green chemistry; |
|
| 99% |
In neat (no solvent) at 80℃; for 0.166667h; Green chemistry; chemoselective reaction; |
General procedure: The reactions were carried out in a 50 mL RB flask under reduced pressure for 10 min at 80°C unless reported differently. In a typical experiment, 5 mmol of amine was added to 5 mmol of BOC anhydride, and the reaction was allowed to proceed for 10 min. The desired product was obtained in a rotary evaporator under vacuum conditions. |
| 99% |
With triethylamine In dichloromethane at 20℃; for 16h; |
|
| 99% |
With triethylamine In dichloromethane at 20℃; for 4h; |
|
| 99% |
With sulfated polyborate In neat (no solvent) at 20℃; for 0.0333333h; Sonication; Green chemistry; chemoselective reaction; |
1.2. Representative procedure for the synthesis of N-tert-butyl carbamate under ultrasonic irradiation.
General procedure: A mixture of amine (2 mmol) and Boc2O (2 mmol), and sulfated polyborate (10 wt%) was sonicated using 20 kHz frequency and 35W power at room temperature in 25mL round bottom flask for stipulated time (progress was monitored by TLC). After complete consumption of the starting materials (TLC), the reaction mixture was cooled to room temperature. The crude mixture was dissolved in the ethyl acetate and the insoluble catalyst was separated using simple filtration then dried and reused. The filtrate was washed with water, dried over sodium sulfate, and concentrated in vacuo to furnish the corresponding N-tert-butyl carbamate derivatives of amines in excellent (87-99%) yields. |
| 98% |
With lanthanum(III) nitrate at 20℃; for 0.0333333h; |
|
| 98% |
With triethylamine In dichloromethane at 20℃; for 24h; Inert atmosphere; |
|
| 98% |
With 12-TPA/SBA 15 at 20℃; for 0.0333333h; Neat (no solvent); |
|
| 98% |
With succinimide-N-sulfonic acid at 20℃; for 0.0166667h; Neat (no solvent); |
|
| 98% |
With Amberlyst A21 In neat (no solvent) at 20℃; for 0.0333333h; Green chemistry; |
General experimental procedure for the N-Boc protection of amines using Amberlyst A21 catalyst
General procedure: Amberlyst A21 (20 wt %) was added to a mixture of amine (1 mmole) and (Boc)2O (1 mmole) and the mixture was stirred for the appropriate reaction time as specified in (Table 1). The progress of reaction was monitored by Thin layer chromatography (10-20% ethyl acetate: hexane) on TLC plates (Merck) precoated with silica. After completion of reaction, the reaction mass was diluted with methanol, filtered off the catalyst which was washed for several times and then dried at 800 °C under reduced pressure for 1 hour and subjected to further recycle study (Table 4). It showed no much more decrease in the product yield indicating high activity of the catalyst. The filtrate was concentrated on rotavacc and the product was purified by column chromatography to afford pure products. |
| 98% |
With triethylamine In dichloromethane at 0℃; for 6h; Inert atmosphere; |
|
| 98% |
With phenylsulfonic acid supported on mesoporous silica SBA-15 In neat (no solvent) at 20℃; for 0.0833333h; Green chemistry; |
General procedure for the N-Boc protection of amines and amino acidsin presence of SBA-15-Ph-SO3H under solvent-free condition
General procedure: An amine (1 mmol) was added to a magnetically stirred mixture of SBA-15-Ph-SO3H (1 mol %, 4 mg) and (Boc)2O (1.1 mmol) at room temperature. The progressof the reaction was monitored by thin-layer chromatography (TLC). After completion of the reaction, the reaction mixture was diluted with EtOH (5 mL)and centrifuged. Then the clear liquid was separated, and the residue containing the catalyst was kept for recovery. EtOH was distilled off under vacuum to yield the highly pure N-Boc derivative. |
| 98% |
With propane-1,2,3-triol at 20℃; for 0.0833333h; Green chemistry; chemoselective reaction; |
|
| 98% |
With nanocerium oxide In neat (no solvent) at 20℃; for 0.0833333h; |
2. General procedure for N-Boc protection of amines
General procedure: To a mixture of amines (1mmol) and Boc2O (1mmol), 10mol% nanocerium oxidewas added wit h vigorous stirring at room temperature for stipulated time. Aftercompletion of reaction as monitored by TLC, diethyl ether was added and the catalyst wasremoved by simple filtration. After removal of the solvent, the pure products wereobtained and no recrystallization or column chromatography was needed. |
| 98% |
With thiamine chloride hydrochloride In neat (no solvent) at 20℃; for 0.05h; |
General procedure for N-Boc protection of amines
General procedure: A mixture of amine (1 mmol), (Boc)2O (1 mmol) and VB1 (2 mol%) was vigorously stirred at room temperature for appropriate time until complete disappearance of amines was observed in the TLC monitoring. After the completion of reactions, the reaction mixture was diluted with ethyl acetate and the VB1 catalyst was isolated by simple filtration. After drying catalyst, it is reused for N-Boc protection of amines. The product in ethyl acetate was washed with water and excess of solvent removed under reduced pressure. The pure products N-tert-butylcarbamate derivatives of amines were obtained in 83-99% yield. The structure of synthesized compounds analyzed by 1H NMR, 13C NMR and mass spectrometry. |
| 97% |
With PEG-400 at 20℃; for 0.5h; Neat (no solvent); |
|
| 96% |
With triethylamine In dichloromethane at 20℃; for 2h; |
|
| 96% |
In lithium hydroxide monohydrate at 30 - 35℃; for 0.0833333h; |
|
| 96% |
With β-cyclodextrins In methanol; propan-2-one at 20℃; for 0.116667h; |
|
| 96% |
With zirconium tetrachloride In acetonitrile at 20℃; for 0.05h; |
|
| 96% |
With sulfonic acid-functionalized ordered nanoporous Na+-montmorillonite at 20℃; for 0.0166667h; Neat (no solvent); |
|
| 96% |
In neat (no solvent) at 100℃; for 0.0833333h; Microwave irradiation; Green chemistry; chemoselective reaction; |
(General procedure for the N-tert-butoxycarbonylation of amines:
General procedure: Amine (1 mmol) and di-tert-butyl dicarbonate [(Boc)2O] (1.1 mmol) were placed in a microwave reaction vial. The LG microwave oven MG 555f was programmed to 300 W at 100 °C. The reaction was monitored using TLC. After the reaction, ice water was added to the reaction mixture which resulted in the precipitation of the product. The solid product was merely filtered off and washed with excess cold water. The product was pure enough for all practical purposes. For characterization purpose, it was further purified by column chromatography (Neutral Alumina as adsorbent, solvent system: Hexane: Ethyl acetate (7.5:2.5)). |
| 96% |
With poly(4-vinylpyridine) at 20℃; for 0.0166667h; |
|
| 96% |
With 1,3-disulfonic acid imidazolium hydrogen sulfate In neat (no solvent) at 20℃; for 0.0166667h; Green chemistry; chemoselective reaction; |
2.4 General procedure for the N-Boc protection of amines
General procedure: Amine (1 mmol) was added to the mixture of (Boc)2O (1 mmol) and DSIMHS (6.5 mg, ~ 0.02 mmol) with constant stirring at room temperature under solvent-free conditions. After completion of the reaction (monitored by TLC), ethyl acetate (3 × 5 mL) was added to the reaction mixture and the catalyst was decanted and washed with ethyl acetate (2 × 5 mL) and dried. The product was purified by column chromatography, using ethyl acetate-petroleum ether (2:8) eluent. |
| 96% |
With N-sulfonic acid poly(4-vinyl)pyridinium chloride In neat (no solvent) at 20℃; for 0.0166667h; |
|
| 96% |
With 1,1'-hexane-1,6-diylbis(3-methylpyridinium)tetrachlorocobaltate(II) In neat (no solvent) at 20℃; for 0.166667h; |
|
| 96% |
With succinimidinium hydrogensulfate In neat (no solvent) at 20℃; for 0.0166667h; Green chemistry; |
|
| 96% |
With sulfated tungstate 10 wt % In neat (no solvent) at 20℃; for 0.0833333h; chemoselective reaction; |
2. General procedure for N-Boc protection of amines
General procedure: A mixture of amine (1mmol), (Boc)2O (1mmol) and sulfated tungstate (10wt%) was vigorously stirred at room temperature for appropriate time until complete disappearance of amines was observed in the TLC monitoring. After the completion of reactions, the reaction mixture was diluted with diethyl ether and the catalyst was isolated by simple filtration. After drying catalyst, it is reused for N-Boc protection of amines. The product was isolated in purified form by evaporating the diethyl ether at room temperature. After the evaporation of diethyl ether solvent, the pure products were obtained and no recrystallization or column chromatography was needed for the purification of products. |
| 95% |
Stage #1: di-<i>tert</i>-butyl dicarbonate With molybdenium(VI) dioxodichloride In dichloromethane at 20℃; for 0.5h;
Stage #2: benzylamine In dichloromethane at 20℃; for 0.2h; |
|
| 95% |
With saccharin sulfonic acid In hexane at 20℃; for 1h; |
|
| 95% |
With thioglycoluril In ethanol at 30 - 40℃; for 0.0833333h; chemoselective reaction; |
|
| 95% |
With aniline; 1-n-butyl-3-methylimidazolium bistrifluoromethylsulfonylamide at 30 - 35℃; for 0.0333333h; neat (no solvent); chemoselective reaction; |
|
| 95% |
With sulfonic acid-functionalized nanoporous titania catalyst In neat (no solvent) at 20℃; for 0.333333h; chemoselective reaction; |
2.5. General procedure for synthesis of N-tert-butylcarbamates
General procedure: An amine (1 mmol) was added to a magnetically stirred mixture of TiO2-Pr-SO3H (10 mg) and di-tert-butyl dicarbonate (240 mg, 1.1 mmol) at room temperature. The mixture was stirred until completion of the reaction (TLC), then diluted with EtOAc (10 mL) and filtered. The residue contains only the catalyst and kept for recovery. The filtrate was washed with water (3 x 20 mL) and brine (2 x 20 mL) and dried over anhydrous MgSO4, then solvent was distillated off under vacuum to yield the highly pure N-Boc derivative. |
| 95% |
With Fe3O4 In ethanol at 20℃; for 3.33333h; Green chemistry; chemoselective reaction; |
General procedure for the N-boc protection of amines
General procedure: A round-bottom flask (10 mL), which contains EtOH(5 mL), was charged with a solution of diboc (1-2 mmol),nano-Fe3O4 (3 mol%, 0.007 g) and the amine (1 mmol). The mixture was stirred at room temperature for the appropriate time (Table 3). After completion of the reaction, the catalyst was collected by a magnet and separated from the solution of product and the remaining starting materials.After drying and evaporation of the solvent, the resulting solid was recrystallized from n-hexane or ethyl acetate(5 mL) to give the pure product. The recovered catalyst was washed with EtOH, dried and reused for the next run. The catalyst was recovered and reused for six times without any significant changes in the yield and the reaction time. |
| 95% |
With trimethyl-(2-hydroxyethyl)ammonium chloride; urea at 50℃; Green chemistry; |
General procedure
General procedure: A dried test tube, equipped with a magnetic stir bar, wascharged with 0.5 cm3 DES, amine derivatives(0.5 mmol), and Boc2O (0.5 mmol) and the mixture washeated at 50 C until the reaction was complete (monitoredby TLC and IR). After this time, 5 cm3 water wasadded and in the most cases a white solid was obtained.The solid product was collected by filtration and washedsuccessively with water and recrystallized from ethanolto get the pure final product [51-60]. The viscousproducts extracted with ethyl acetate and were purifiedby column chromatography, using ethyl acetate-petroleumether. |
| 94% |
With iodine at 20℃; for 0.5h; |
|
| 94% |
at 20℃; for 0.133333h; |
|
| 94% |
With N,N,N',N'-tetramethylguanidinium acetate at 20℃; for 0.1h; Neat (no solvent); |
|
| 94% |
With ferric(III) chloride In dichloromethane at 20℃; for 0.25h; |
|
| 94% |
With zinc oxide at 20℃; for 0.1h; |
|
Chemistry
Pharmaceutical Intermediates
Inhibitors/Agonists
Material Science
Life Science
For Research Only
100K+ Compounds
Competitive Price
1-2 Day Shipping
