Hexadienyloxycarbonyl (Hdoc) — A Mild Acid Labile Protecting Group for Amines.

ChemInform ◽  
2004 ◽  
Vol 35 (6) ◽  
Author(s):  
Iain Lingard ◽  
Gurdip Bhalay ◽  
Mark Bradley
Keyword(s):  
Protecting Group ◽  
Acid Labile ◽  
Mild Acid

Hexadienyloxycarbonyl (Hdoc) - A Mild Acid Labile Protecting Group for Amines

Synlett ◽  
2003 ◽  
pp. 1791-1792
Author(s):  
Mark Bradley ◽  
Iain Lingard ◽  
Gurdip Bhalay
Keyword(s):  
Protecting Group ◽  
Acid Labile ◽  
Mild Acid

The synthesis of a carbohydrate-like dihydrooxazine and tetrahydrooxazine as putative inhibitors of glycoside hydrolases: A direct synthesis of isofagomine

2002 ◽  
Vol 80 (8) ◽  
pp. 857-865 ◽  
Author(s):  
Wayne M Best ◽  
James M Macdonald ◽  
Brian W Skelton ◽  
Robert V Stick ◽  
D Matthew G Tilbrook ◽  
...  
Keyword(s):  
Direct Synthesis ◽  
Glycoside Hydrolases ◽  
Crystalline Solid ◽  
Glycosidase Inhibitors ◽  
Protecting Group ◽  
Mild Acid Hydrolysis ◽  
Catalytic Hydrogenolysis ◽  
Palladium On Carbon ◽  
Mild Acid

The treatment of benzyl 2,3-O-isopropylidene-β-L-xylopyranoside with N-hydroxyphthalimide under Mitsunobu conditions, followed by protecting-group interchange, gave benzyl 4-O-[(tert-butoxycarbonyl)amino]-2,3- O-isopropylidene-α-D-arabinoside. Mild acid hydrolysis and catalytic hydrogenolysis afforded 4-O-[(tert-butoxycarbonyl)amino]-D-arabinose that, upon heating in water, gave the dihydrooxazine [(4R,5S,6R)-5,6-dihydro-4,5-dihydroxy-6-hydroxymethyl-4H-1,2-oxazine] as a crystalline solid. A single-crystal structure determination of this solid showed it to exist in the 5H6 conformation. Reduction of the dihydrooxazine gave the tetrahydrooxazine [(4R,5S,6R)-4,5-dihydroxy-6-hydroxymethyl-3,4,5,6-tetrahydro-2H-1,2-oxazine]. The dihydrooxazine was an effective inhibitor of two β-glucosidases (Ki = 27 and 35 µM). Benzyl 2,3-O-isopropylidene-β-L-xylopyranoside, via the derived imidazylate, was converted into a nitrile that, upon reduction and protecting-group manipulations, gave benzyl 4-C-aminomethyl-4-deoxy-α-D-arabinoside. Treatment of this amine with hydrogen and palladium-on-carbon gave isofagomine.Key words: dihydrooxazine, tetrahydrooxazine, isofagomine, iminosugars, glycosidase inhibitors.

Cyclopropyldimethylcarbinyl: A new acid-labile side-chain protecting group for asparagine and glutamine

Peptides 1994 ◽  
1995 ◽  
pp. 155-156
Author(s):  
L. A. Carpino ◽  
H. N. Shroff ◽  
H.-G. Chao ◽  
E. M. E. Mansour ◽  
F. Albericio
Keyword(s):  
Side Chain ◽  
Protecting Group ◽  
Acid Labile

scholarly journals 2,3-Diaminopropanols Obtained from d-Serine as Intermediates in the Synthesis of Protected 2,3-l-Diaminopropanoic Acid (l-Dap) Methyl Esters

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1313
Author(s):  
Andrea Temperini ◽  
Donatella Aiello ◽  
Fabio Mazzotti ◽  
Constantinos M. Athanassopoulos ◽  
Pierantonio De Luca ◽  
...  
Keyword(s):  
Amino Acid ◽  
Reductive Amination ◽  
Methyl Esters ◽  
Primary Amines ◽  
Synthetic Approach ◽  
Protecting Group ◽  
Synthetic Strategy ◽  
Crude Product ◽  
Diaminopropanoic Acid ◽  
Acid Labile

A synthetic strategy for the preparation of two orthogonally protected methyl esters of the non-proteinogenic amino acid 2,3-l-diaminopropanoic acid (l-Dap) was developed. In these structures, the base-labile protecting group 9-fluorenylmethyloxycarbonyl (Fmoc) was paired to the p-toluensulfonyl (tosyl, Ts) or acid-labile tert-butyloxycarbonyl (Boc) moieties. The synthetic approach to protected l-Dap methyl esters uses appropriately masked 2,3-diaminopropanols, which are obtained via reductive amination of an aldehyde prepared from the commercial amino acid Nα-Fmoc-O-tert-butyl-d-serine, used as the starting material. Reductive amination is carried out with primary amines and sulfonamides, and the process is assisted by the Lewis acid Ti(OiPr)4. The required carboxyl group is installed by oxidizing the alcoholic function of 2,3-diaminopropanols bearing the tosyl or benzyl protecting group on the 3-NH2 site. The procedure can easily be applied using the crude product obtained after each step, minimizing the need for chromatographic purifications. Chirality of the carbon atom of the starting d-serine template is preserved throughout all synthetic steps.

scholarly journals Stepwise PEG synthesis featuring deprotection and coupling in one pot

2021 ◽  
Vol 17 ◽  
pp. 2976-2982
Author(s):  
Logan Mikesell ◽  
Dhananjani N A M Eriyagama ◽  
Yipeng Yin ◽  
Bao-Yuan Lu ◽  
Shiyue Fang
Keyword(s):  
Synthesis Method ◽  
Polyethylene Glycols ◽  
Protecting Group ◽  
One Pot ◽  
Isolation And Purification ◽  
Stepwise Synthesis ◽  
Convenient Approach ◽  
Formation Conditions ◽  
The One ◽  
Acid Labile

The stepwise synthesis of monodisperse polyethylene glycols (PEGs) and their derivatives usually involves using an acid-labile protecting group such as DMTr and coupling the two PEG moieties together under basic Williamson ether formation conditions. Using this approach, each elongation of PEG is achieved in three steps – deprotection, deprotonation and coupling – in two pots. Here, we report a more convenient approach for PEG synthesis featuring the use of a base-labile protecting group such as the phenethyl group. Using this approach, each elongation of PEG can be achieved in two steps – deprotection and coupling – in only one pot. The deprotonation step, and the isolation and purification of the intermediate product after deprotection using existing approaches are no longer needed when the one-pot approach is used. Because the stepwise PEG synthesis usually requires multiple PEG elongation cycles, the new PEG synthesis method is expected to significantly lower PEG synthesis cost.

scholarly journals Synthesis of 1,2-Dihydroquinolines via Hydrazine-Catalysed Ring-Closing Carbonyl-Olefin Metathesis

2019 ◽  
Author(s):  
Yunfei Zhang ◽  
Jae Hun Sim ◽  
Samantha N. Macmillan ◽  
Tristan Lambert
Keyword(s):  
Nitrogen Atom ◽  
Olefin Metathesis ◽  
Catalytic Cycle ◽  
Protecting Group ◽  
Acid Labile

The synthesis of 1,2-dihydroquinolines by the hydrazine-catalysed ring-closing carbonyl-olefin metathesis (RCCOM) of N-prenylated 2-aminobenzaldehydes is reported. Substrates with a variety of substitution patterns are shown, and the compatibility of these conditions with a range of additives is demonstrated. With an acid-labile protecting group on the nitrogen atom, in situ deprotection and autoxidation furnishes quinolines. In comparison to related oxygen-containing substrates, the cycloaddition step of the catalytic cycle is shown to be slower, but the cycloreversion is found to be more facile.

scholarly journals Revisiting NO2 as Protecting Group of Arginine in Solid-Phase Peptide Synthesis

2020 ◽  
Vol 21 (12) ◽  
pp. 4464
Author(s):  
Mahama Alhassan ◽  
Ashish Kumar ◽  
John Lopez ◽  
Fernando Albericio ◽  
Beatriz G. de la Torre
Keyword(s):  
Peptide Synthesis ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Side Reaction ◽  
Reducing Agent ◽  
Protecting Groups ◽  
Side Chain ◽  
Protecting Group ◽  
Mild Acid

The protection of side-chain arginine in solid-phase peptide synthesis requires attention since current protecting groups have several drawbacks. Herein, the NO2 group, which is scarcely used, has been revisited. This work shows that it prevents the formation of δ-lactam, the most severe side-reaction during the incorporation of Arg. Moreover, it is stable in solution for long periods and can be removed in an easy-to-understand manner. Thus, this protecting group can be removed while the protected peptide is still anchored to the resin, with SnCl2 as reducing agent in mild acid conditions using 2-MeTHF as solvent at 55 °C. Furthermore, we demonstrate that sonochemistry can facilitate the removal of NO2 from multiple Arg-containing peptides.

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