19779-75-0

The reaction of tryptophan methyl ester (1) with aldehydes such as benzaldehyde (2a) and cyclohexanecarboxaldehyde (2b) in refluxing benzene provides the corresponding tetrahydro-β-carbolines 5a and 5b, respectively, as earlier reported, in contrast to th

Monocyclic β-lactams revive the research field on antibiotics, which are threatened by the emergence of resistant bacteria. A six-step synthetic route was developed, providing easy access to new 3-amino-1-carboxymethyl-4-phenyl-β-lactams, of which the penicillin-binding protein (PBP) inhibitory potency was demonstrated biochemically.

Developing specific chemical functionalities to deploy in biological environments for targeted enzyme inactivation lies at the heart of mechanism-based inhibitor development but also is central to other protein-tagging methods in modern chemical biology including activity-based protein profiling and proteolysis-targeting chimeras. We describe here a previously unknown class of potential PLP enzyme inactivators; namely, a family of quaternary, α-(1′-fluoro)vinyl amino acids, bearing the side chains of the cognate amino acids. These are obtained by the capture of suitably protected amino acid enolates with β,β-difluorovinyl phenyl sulfone, a new (1′-fluoro)vinyl cation equivalent, and an electrophile that previously eluded synthesis, capture and characterization. A significant variety of biologically relevant AA side chains are tolerated including those for alanine, valine, leucine, methionine, lysine, phenylalanine, tyrosine, and tryptophan. Following addition/elimination, the resulting transoid α-(1′-fluoro)-β-(phenylsulfonyl)vinyl AA-esters undergo smooth sulfone-stannane interchange to stereoselectively give the corresponding transoid α-(1′-fluoro)-β-(tributylstannyl)vinyl AA-esters. Protodestannylation and global deprotection then yield these sterically encumbered and densely functionalized quaternary amino acids. The α-(1′-fluoro)vinyl trigger, a potential allene-generating functionality originally proposed by Abeles, is now available in a quaternary AA context for the first time. In an initial test of this new inhibitor class, α-(1′-fluoro)vinyllysine is seen to act as a time-dependent, irreversible inactivator of lysine decarboxylase from Hafnia alvei. The enantiomers of the inhibitor could be resolved, and each is seen to give time-dependent inactivation with this enzyme. Kitz-Wilson analysis reveals similar inactivation parameters for the two antipodes, L-α-(1′-fluoro)vinyllysine (Ki = 630 ± 20 μM; t1/2 = 2.8 min) and D-α-(1′-fluoro)vinyllysine (Ki = 470 ± 30 μM; t1/2 = 3.6 min). The stage is now set for exploration of the efficacy of this trigger in other PLP-enzyme active sites.

The simultaneous control of diastereoselectivity and regioselectivity in Zn-catalyzed allenylation reactions of N-protected l-α-amino aldehydes is reported. A reversal in diastereoselectivity could be realized by variation of the α-amino aldehyde protecti

The new Ag2CO3/CA-AA-amidphos complexes have been demonstrated as highly efficient multifunctional catalysts in the asymmetric 1,3-dipolar cycloaddition of azomethine ylides. Under optimal conditions, highly functionalized endo-4 pyrrolidines were obtained with excellent yields (up to 99% yield) and enantioselectivities (up to 96% ee).

A novel and highly efficient AgOAc/TF-BiphamPhos catalytic system shows excellent reactivity, diastereo-/enantioselectivity and structural scope in asymmetric 1,3-dipolar cycloaddition of azomethine ylides, especially derived from various α-substituted α-amino acids, with N-substituted maleimides and other electron-deficient alkenes.

Compounds with cancer cell specific lethality are provided. In particular, RAS-selective lethal compounds and compositions are provided. Also provided are methods of screening for such compounds and methods of treating a condition in a mammal, by administering to the mammal a therapeutically effective amount of such compounds or compositions.

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(Chemical Equation Presented) The facile, two-pot synthesis of N-methyl amino acid esters by way of reductive amination is presented. Side chain protection schemes are not required, the starting materials are all commercially available, and the synthetic

The enantiomer of affinisine has been synthesized (from L-tryptophan) with 100% diastereoselectivity via the asymmetric Pictet-Spengler reaction coupled with a Pd°(enolate mediated) coupling process. This enantiomer has also been converted into a key inte

Tryprostatin B and demethoxyfumitremorgin C are fungal inhibitors of mammalian cell cycle progression at the G2/M transition. N-Alkyl derivatives of the L-Trp-L-Pro diketopiperazine were prepared as analogues of tryprostatin B, and two of these

Condensations of L-tryptophan-derived 2-[(methoxycarbonyl)methyl]-3- [2(S)-(benzyloxycarbonyl)-2-(N(b)-benzylamino)ethyl]indole (6) with 4,4- dimethoxyacrolein or with 2,4-hexadienal, followed by removal of the tryptophanyl ester function, respectively gave the tetracyclic acetal (-)- methyl (2S,-3aS,5R,11bR)-3-benzyl-2,3,3a,4,5,7-hexahydro-5- (dimethoxymethyl)-1H-pyrrolol[2,3-d]carbazole-6-carboxylate (10) or the tetracyclic olefin (-)-methyl (2S,3aS,5R,11bR)-3-benzyl-2,3,3a,4,5,7- hexahydro-5-(1-propenyl)-1H-pyrrolo[2,3-d]carbazole-6-carboxylate (14). Their respective hydrolysis or oxidation provided, enantioselectively, the tetracyclic aldehyde (-)-methyl (2S,3aS,5R,11bR)-3-benzyl-2,3,3a,4,5,7- hexahydro-5-formyl-1H-pyrrolo[2,3-d]carbazole-6-carboxylate (5). Its reaction with tri-n-butyl-1-(ethoxy)ethoxymethyltin and n-butyllithium, followed by oxidation of the resultant alcohol (-)-methyl (2S,3aS,5R,11bR)-3-benzyl- 2,3,3a,4,5,7-hexahydro-5-(1ξ-hydroxy-2-((1-ethoxy-ethoxy))ethyl-1H- pyrrolo[2,3-d]carbazole-6-carboxylate (16) and cyclization furnished the pentacyclic ketone (-)-methyl (2S,3aS,SR,11bR)-3-benzyl-2,3,3a,4,5,7- hexahydro-3,5-ethano-12-oxo-1H-pyrrolo-[2,3-d]carbazole-6-carboxylate (15). A Horner-Emmons condensation led to the unsaturated esters (-)-methyl (2S,3aS,5R,11bR)-3-benzyl-2,3,3a,4,5,7-hexahydro-3,5-ethano-12-(E and Z)- [(methoxycarbonyl)-methylene]-1H-pyrrolo[2,3-d]carbazole-6-carboxylates (19 and 20) with 17:1 E/Z selectivity. Reductions of the ester and vinylegous urethane functions in 19 led to the Wieland-Gumlich aldehyde 3 as a 6:1 anomeric hemiacetal mixture. Its condensation with malonic acid provided (- )-strychnine (1) in 5.3% overall yield and 14 steps from the tryptophan derivative 6.

A series of N-substituted amino acid derivatives was synthesized and the compounds were evaluated for their effects on serum total cholesterol, HDL cholesterol and triglycerides in experimental animals.Hyperalphalipoproteinaemic activity was found for some of these compounds tested, especially BRL 26314 (2) and related 3-aryl-2-aminopropionic acids.Structure-activity relationships are discussed.Keywords: N-substituted amino acid derivatives / hyperalphalipoproteinaemic activity

The Pictet-Spengler cyclisation of the benzylideneimine of tryptophan methyl ester in xylene, contrary to literature reports, occurs extremely slowly, if at all, in the absence of acids.The cyclisation is Bronsted acid catalysed and the rate of cyclisatio

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