856865-59-3

Upstream product

• 1694-92-4 2-Nitrobenzenesulfonyl chloride 
• 132388-59-1 L-Asn(Trt) 
• 67-56-1 methanol 

Downstream Products

• 856865-75-3 N₂-methyl-N₂-[(2-nitrophenyl)sulfonyl]-N-(triphenylmethyl)-L-asparagine methyl ester 
• 856865-96-8 N-α-methyl-N-α-(o-nitrobenzenesulfonyl)-N-β-trityl-L-asparagine 

Relevant academic research and scientific papers

Total Synthesis of Aurantoside G, an N-β-Glycosylated 3-Oligoenoyltetramic Acid from Theonella swinhoei

The first synthesis of a natural N-glycosylated 3-acyltetramic acid is reported. Aurantoside G (1 g), a deep-red metabolite of the marine sponge Theonella swinhoei, is highly delicate in the pure state. It features a chlorinated dodecapentaenoyl side chain at an l-asparagine-derived tetramic acid, the ring nitrogen atom of which is linked to a β-configured d-xylose. The side chain was built through consecutive Wittig and HWE reactions and used to N-acylate the amino group of an asparaginate that had already been N-xylosylated through a Fukuyama–Mitsunobu reaction. This N-acylation step fixes the β-configuration of the xylose, which is essential for the antifungal activity, but only if the sugar carries bulky, electron-rich protecting groups such as PMB. In the final step, the heterocycle was closed quantitatively through a basic Lacey–Dieckmann condensation of an entirely unprotected precursor.

Environmentally Friendly SPPS II: Scope of Green Fmoc Removal Protocol Using NaOH and Its Application for Synthesis of Commercial Drug Triptorelin

With the growing necessity to consider environmental impacts when synthesizing peptide-based drugs and to expand upon the recently published short communication report, we herein present a thorough evaluation of a green Fmoc removal protocol. Our protocol avoids the use of hazardous components (using piperidine as a base and dichloromethane (DCM) and N,N-dimethylformamide (DMF) as solvents) and relies on the utilization of the green mineral base NaOH in combination with the greener solvent 2-methyltetrahydrofuran (2-MeTHF) mixed with MeOH. For the original Fmoc removal cocktail (solvents ratio of 1:1), we evaluated the impact of quality/purity of the used 2-MeTHF, scale-up, ratio of 2-MeTHF/MeOH, utilized hydroxide, temperature, and reaction time. An alternative 3:1 protocol was examined using various amino acids, and only Gly required the optimization of the Fmoc removal cocktail composition. The optimized protocol used to remove Fmoc from Gly residue was proved by the synthesis of Leu-enkephalin. We also investigated the stability of the conventional amino acid side-chain-protecting groups, t-Bu, Boc, Trt, and Pbf, and the formation of aspartimide as an undesirable side reaction that occurs during Fmoc solid-phase peptide synthesis (SPPS). The applicability of this synthesis strategy was documented by evaluating the SPPS of a commercial drug used for prostate and breast cancer treatments - decapeptide triptorelin.

Convenient synthesis of N-methylamino acids compatible with Fmoc solid-phase peptide synthesis

Nα-Methylamino acid containing peptides exhibit interesting therapeutic profiles and are increasingly recognized as potentially useful therapeutics. Unfortunately, their synthesis is hampered by the high price and unavaibility of many Nα/