203873-66-9

Upstream product

• 7517-19-3 methyl (L)-leucinate hydrochloride 
• 98-74-8 4-Nitrobenzenesulfonyl chloride 
• 2666-93-5 (S)-Leu-OMe 

Downstream Products

• 610800-52-7 N-methyl-N-nosyl-L-leucine methyl ester 
• 916049-49-5 2-[(3-benzyloxycarbonylaminopropionyl)methoxymethylamino]-4-methylpentanoic acid methyl ester 
• 916049-34-8 2-[(3-benzyloxycarbonylaminopropionyl)trimethylsilylmethylamino]-4-methylpentanoic acid methyl ester 
• 1243654-89-8 N-ethyl-N-nosyl-L-leucine methyl ester 
• 1492-11-1 N-acetyl-L-leucine methyl ester 
• 2666-93-5 (S)-Leu-OMe 
• 916049-31-5 4-methyl-2-[(4-nitrobenzenesulfonyl)trimethylsilanylmethylamino]pentanoic acid methyl ester 
• 203873-69-2 (S)-methyl 2-(N-allyl-4-nitrophenylsulfonamido)-4-methylpentanoate 

Relevant academic research and scientific papers

Chemoselective Intramolecular Functionalization of Methyl Groups in Nonconstrained Molecules Promoted by N-Iodosulfonamides

Mechanistic evidence observed in Hofmann-L?ffler-Freytag-type reactions has been crucial to achieve the chemoselective functionalization of methyl groups under mild conditions. Radical-mediated methyl iodination and subsequent oxidative deiodination are the key steps in this functionalization, where iodine chemistry has a pivotal role on the formation of the C-N bond. The concepts of single hydrogen atom transfer (SHAT) and multiple hydrogen atom transfer (MHAT) are introduced to describe the observed chemoselectivity. (Chemical Equation Presented).

DBU Catalysed Enantioselective Degradative Rearrangement: a Way to Tetrasubstituted 2-Aryl-2-Amino Esters

Herein we report a catalytic, easily scalable protocol for the enantioselective synthesis of Tetrasubstituted α-aryl-α-amino acid derivatives, using a biphasic system composed by catalytic DBU in DME and aqueous solutions of Na2CO3. Under very mild reaction conditions, without using metal or chiral additives, this heterogeneous system promotes the degradative rearrangement of functionalized N-aryl sulphonyl α-amino esters into the corresponding tetrasubstituted 2-aryl-2-amino esters, with high enantiomeric ratios (up to 97.5:2.5) and good yields (up to 95%). (Figure presented.).

Synthesis of Optically Active 2,3-Disubstituted Indoline -Derivatives through Cycloaddition Reactions between Benzynes and α,β-Unsaturated γ-Aminobutyronitriles

We report a method for synthesizing optically active 2,3-disubstituted indolines by the cycloaddition reaction of benzynes with various 4-[(4-toluenesulfonyl)amino]-(E)-but-2-enenitriles, which are readily prepared from the corresponding l -amino acid der

Synthesis of enantioenriched 1,2-trans-diamines using the borono-Mannich reaction with N-protected α-amino aldehydes

The three-component Petasis borono-Mannich reaction starting with easily accessible N-protected α-amino aldehydes produces efficiently and diastereoselectively 1,2-trans-diamines with an enantiomeric excess of up to 98%.

Building functionalized peptidomimetics: Use of electroauxiliaries for introducing N-acyliminium ions into peptides

A series of silyl-substituted amino acids have been synthesized, inserted into peptides, and then employed as precursors for oxidatively generating reactive N-acyliminium ions. Both electrochemical and chemical oxidation procedures have been employed. N-Acyliminium ion generation in a solid-phase substrate as well as application to a small library of functionalized dipeptides has been demonstrated. Limitations in terms of how electron-rich the silyl groups can be as well as the compatibility of multiple silyl groups within a longer peptide are defined.

"One-pot" methylation of N-nosyl-α-amino acid methyl esters with diazomethane and their coupling to prepare N-methyl dipeptides

N-Nosyl-α-amino acid methyl esters are methylated quantitatively with diazomethane. After proper deprotection of the amino function by treatment with the reagent system mercaptoacetic acid/sodium methoxide, the obtained N-methyl amino acid methyl esters are coupled with N-Fmoe amino acid chlorides to afford the corresponding dipeptides. The obtained products do not show any detectable extent of racemization by 1H NMR and HPLC.

Synthesis of cyclic dipeptides by ring-closing metathesis

Several cyclic dipeptides (4a-g and 9a-c) have been synthesized by 'amide-to-amide' cyclization of 2a-g and 8a-c, respectively, by means of ring-closing metathesis employing the Grubbs ruthenium catalyst. The influence of additives as well as the length of the amide substituent were studied. Best yields were obtained by cyclization in solution with either lithium fluoroacetate or α,α-dichlorotoluene as an additive.

Site-specific N-alkylation of peptides on the solid phase

A convenient approach, featuring a Mitsunobu reaction, is described for the introduction of an alkyl group at a specific amide function of a peptide on the solid phase. This 'site-specific alkylation' procedure is illustrated with an N-ethyl scan of Leu-enkephalin.