121071-92-9

Upstream product

• 420-37-1 trimethoxonium tetrafluoroborate 
• 131827-27-5 5-hydroxy-6-(1H-indol-3-ylmethyl)-3-(2-methylpropyl)pyrazin-2(1H)-one 4-oxide 
• 131827-29-7 2-(tert-butoxycarbonyloxy)-6-(1H-indol-3-ylmethyl)-5-methoxy-3-(2-methylpropyl)pyrazine 4-oxide 
• 168766-50-5 1-(2-cyanoethyl)-3-isobutyl-5-hydroxy-6-(indol-3-yl)-methyl-1,2-dihydropyrazin-2-one 4-oxide 
• 168766-86-7 N-(2-cyanoethyl)-N-(2-hydroxyiminoisohexanoyl)-L-tryptophan benzyl ester 
• 298696-11-4 N-[2-(2-cyanoethoxyimino)isohexanoyl]-N-(2-cyanoethyl)-L-tryptophan methyl ester 
• 76617-78-2 2-(hydroxyimino)-4-methylpentanoic acid 
• 131827-99-1 (S)-N-(2-hydroxyimino-4-methylvaleryl)tryptophan methyl ester 
• 7303-49-3 DL-tryptophan methyl ester 
• 4299-70-1 L-tryptophan methyl ester 
• 131828-02-9 (S)-N-(2-hydroxyimino-4-methylvaleryl)tryptophan 
• 138039-95-9 2-{2-[(E)-Hydroxyimino]-4-methyl-pentanoylamino}-3-(1H-indol-3-yl)-propionic acid 2,5-dioxo-pyrrolidin-1-yl ester 
• 131827-28-6 2-(tert-butoxycarbonyloxy)-5-hydroxy-6-(1H-indol-3-ylmethyl)-3-(2-methylpropyl)pyrazine 4-oxide 
• 131827-99-1 N-(2-hydroxyimino-4-methylvaleryl)tryptophan methyl ester 

Relevant academic research and scientific papers

Progress in the synthesis of OPC-15161: Easy access to dioxygenated pyrazine N-oxide structure

An improved synthetic route to OPC-15161 (1), a novel inhibitor of superoxide anion generation, is described. Choice of the protecting group is the key to the second-generation synthesis. Usefulness of the 2-cyanoethyl (CE)-protecting group in our process research is emphasized in comparison with that of other protecting groups. This process can be carried out in four steps with 40% overall yield from tryptophan methyl ester, which also opens a general route for the preparation of the related 5-alkoxypyrazin-2(1H)-one 4-oxides.

A novel thiolate mediated cyclization to OPC-15161

An efficient synthetic route to OPC-15161 (1) was developed via novel pyrazine ring closure promoted by a lithium thiolate anion. The key intermediate (4) was prepared in a one-pot procedure by treating the methyl ester (2) with a lithium arylthiolate. This protocol does not require a free acid intermediate and thus can establish the shortest route to pyrazine dioxide skeleton from tryptophan ester derivatives. In the present transformation, lithium arylthiolates could behave like aluminium arylthiolates, and not like lithium alkylthiolates that often cleave esters to the corresponding acids. One-pot reactions that involve lengthy multiple steps in a single flask are of significant importance in contemporary organic synthesis. Utilization of a catalytic or stoichiometric promoter which can facilitate several transformations is a key to the success of such reactions. In this paper, we would like to disclose an interesting one-pot transformation discovered in our process research, which offered us novel information on the reactivity of metal thiolates. Main feature of our one-pot process is a merged deprotection-cyclization sequence. (C) 2000 Elsevier Science Ltd.

Synthesis of 2,5-Dioxygenated Pyrazine 4-Oxides: Total Synthesis of a New Inhibitor of Superoxide Anion Generation, OPC-15161

The total synthesis of OPC-15161 1, a new inhibitor of superoxide anion generation, is described in full.Three approaches, routes A-C, have been investigated focusing on the pivotal structure 2,5-dioxygenated pyrazine 4-oxide.Among them, route A led to the total synthesis of 1.That is, the key precursor, 5-hydroxypyrazin-2(1H)-one 4-oxide 7 has been prepared from tryptophan methyl ester 2 in three steps, and direct methylation of the 5-hydroxy group of 7 or three-step methylation via the 2-O-Boc derivative 10 afforded 1 in 9.9-10.6percent overall yields.

Indole derivatives

The novel indole derivatives and salts thereof represented by the general formula (1) STR1 possess, for example, an inhibitory effect against superoxide (O2-) released from the macrophage cells of guinea pig by stimulation and an anti-albuminuria activity against Masugi nephritis, and are useful in various clinical fields as an agent for preventing and treating diseases and cases associated with the above superoxide radical, for example, autoimmune diseases (e.g. rheumatism), arteriosclerosis, ischemic disease, ischemic encephalopathia, hepatic insufficiency and renal insufficiency, and also as an agent for preventing and treating nephritis.

TOTAL SYNTHESIS OF A NEW INHIBITOR OF SUPEROXIDE ANION GENERATION, OPC-15161

The first total synthesis of a new inhibitor of superoxide anion generation, OPC-15161, was achieved from tryptophan methyl ester in 4-6 steps in 9.9-10.6percent overall yields.

The First Total Synthesis of OPC-15161

The first total synthesis of OPC-15161, a novel inhibitor of superoxide generation by guinea pig macrophages, has been accomplished via a convergent and efficient route exploiting the coupling of the fully functionalized pyrazine part with the indolyl gro