28024-78-4

Upstream product

• 20850-33-3 ethyl 2-acetamido-2-cyano-4-methyl-4-pentenoate 
• 31918-30-6 2-Oximino-4-methyl-4-pentensaeureethylester 
• 1575-67-3 2-(2-methyl-allyl)-malonic acid diethyl ester 
• 80741-44-2 ethyl 2-<(diphenylmethylene)amino>-4-methyl-(+/-)-4-pentenoate 
• 4746-62-7 2-amino-2-hydroxyacetic acid 
• 167773-10-6 4,4,5,5-tetramethyl-2-(2-methylallyl)-1,3,2-dioxaborolane 
• 68843-73-2 ethyl (2RS)-2-amino-4-methyl-4-pentenoate 
• 87325-65-3 (R,S)-2-acetamido-4-methyl-4-pentenoic acid 
• 31918-40-8 2-Oximino-4-methyl-4-pentensaeure 

Downstream Products

• 65427-58-9 2-benzoylamino-4-methyl-pent-4-enoic acid 
• 15722-67-5 3-amino-5,5-dimethyltetrahydro-2-furanone (hydrochloride) 
• 131177-58-7 Fmoc-4,5-didehydro-DL-leucine 

Relevant academic research and scientific papers

Peptides containing γ,δ,-dihydroxy-L-leucine

(Chemical Equation Presented) (±)-Dehydroleucine was prepared and resolved by porcine kidney acylase. Under the conditions of the Sharpless asymmetric dihydroxylation (SAD), employing AD-mix-α, Nα- carbobenzyloxy-(2S)-4,5-dehydroleucine methyl ester (16)

Direct synthesis of unprotected α-amino acids via allylation of hydroxyglycine

Hydroxyglycine, the ammonia adduct of glyoxylic acid, was found to react with various allylboronates in the presence of triethylamine in methanol to give unprotected α-amino acids directly with high stereoselectivity. For instance, the reactions with (E)- and (Z)-crotylboronates afforded the corresponding anti- and syn-crotylated products (isoleucine and alloisoleucine after hydrogenation) with high diastereoselectivity, respectively. Interestingly, it was found that isomerization of the products (γ-adducts to α-adducts) occurred under the reaction conditions in some cases. Control experiments have suggested that the isomerization took place via 2-aza (or azonia) Cope rearrangement of imines derived from γ-adducts and glyoxylic acid.

The asymmetric synthesis of allylglycine and other unnatural α-amino acid via zinc-mediated allylation of oximes in aqueous media

Enantiomerically pure or highly enriched allylglycine and its chain-substituted analogs are easily accessible from the reaction of the sultam derivative of O-benzyl glyoxylic acid oxime with allylic bromides in the presence of powdered zinc in aqueous ammonium chloride.

Synthesis of 2>Leu-enkephalin and 2,D-Leu5>Leu-enkephalin with High Specific Tritiated Activity in the Leucine Residue

2>Leu-enkephalin and 2,D-Leu5>Leu-enkephalin (DADLE) labelled with tritium in the leucine residue have been prepared.Synthesis of the precursor peptides, 2,4,5-didehydro-L-Leu5>Leu-enkephalin and 2,4,5-didehydro-D-Leu5>Leu-enkephalin, was carried out by solid-phase synthesis using Fmoc amino acid derivatives, followed by diastereoisomeric separation on HPLC.These peptides were tritiated catalytically to yield DALE with a specific activity of 5.35 TBq mmol-1 and DADLE with that of 5.43 TBq mmol-1, respectively.The distribution of tritium label was investigated by HPLC with a radioisotopic detector following acidic hydrolysis, which confirmed that the tritium label in both labelled peptides was exclusively located at the leucine residue.

THE SYNTHESIS OF AMINO ACIDS BY REACTION OF AN ELECTROPHILIC GLYCINE CATION EQUIVALENT WITH NEUTRAL CARBON NUCLEOPHILES

Seven neutral carbon nucleophiles (active aromatics, allylsilanes and a silyl enol ether) were reacted with the glycine cation equivalent 12 in the presence of TiCl4 to yield α-substituted amino acid derivatives in moderate yield (1-61.5 mmolar scale).Deprotection of the Schiff base ester products led to the corresponding amino acids.