Rapid deprotection of N-Boc amines by TFA combined with freebase generation using basic ion-exchange resins

Abstract

The deprotection of N-Boc amines was rapidly accomplished using 5 equivalents of TFA in methylene chloride in a focused microwave instrument with irradiation at 60 degrees C for 30 min. The freebase amines are then obtained by scavenging the crude reaction mixture with the basic Amberlyst A-21 ion-exchange resin. This procedure is suitable for the parallel deprotection of N-Boc amines.

Preparation and Chemical Properties of π-Conjugated Polymers Containing Indigo Unit in the Main Chain

“…The GPC curve of this polymer (eluent = NMP) showed a unimodal molecular weight distribution, with a peak molecular weight ( M p ) of 18,000 and M w of 26,000, respectively. Deprotection of the BOC group in P(BOCI-Flu) was carried out by treatment of this polymer with CF 3 COOH [23] and P(I-Flu) was obtained as a deep green solid in a quantitative yield. BOC-deprotected P(I-Flu) obtained thus was insoluble in common organic solvents and partly soluble in formic acid.…”

“…The IR data shown in Figure 2 indicate that the deprotection of P(BOCI-Flu) with CF 3 COOH [23] also proceeds cleanly. After the deprotection of the BOC group, P(BOCI-Flu) became insoluble in organic solvents, in spite of the presence of two octyl groups at the fluorene unit, presumably due to the formation of intermolecular hydrogen bonds between the N–H group and the C=O carbonyl group [31,32].…”

Mechanistic Investigations and Substrate Scope Evaluation of Ruthenium-Catalyzed Direct sp3 Arylation of Benzylic Positions Directed by 3-Substituted Pyridines

“…The Boc-protected compounds can be used in further reactions or deprotected by well-established protocols. 19 …”

Novel benzidine and diaminofluorene prolinamide derivatives as potent hepatitis C virus NS5A inhibitors

“…Initially, we wanted to evaluate the antiviral activity of the proline variation; therefore, L-proline isosteres were employed, such as D-proline, 4-oxo-L-proline, L-thioproline, L-pipecolic acid, D-pipecolic acid, and a-methyl-L-proline, by using the standard peptide coupling protocol of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) in dichloromethane (DCM). After purification of intermediates 2e8 through chromatographic columns, the Boc groups of the secondary amine site was removed with diluted trifluoroacetic acid (TFA) in DCM [73]. Then methoxycarbonyl phenylglycine 9 was coupled with the free amine with the aid of EDCI and N,N-diisopropylethylamine (DIPEA) in DCM.…”