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The dipeptide and tripeptide analogues salicyl-L-aspartic acid (Sal-L-Asp) and salicylglycyl-L-aspartic acid (SalGly-L-Asp) were synthesized and their protonation and complex formation with VIVO2+ were studied in aqueous solution through the use of pH-potentiometry and spectroscopic (UV-Vis, CD and EPR) techniques. The phenolate terminus proved to be a good anchoring site to promote (i) the metal ion-induced deprotonation and subsequent coordination of the peptide amide group(s) in the pH range 4-5 for the dipeptide analogue, (ii) and in the pH range 5-6 in a very cooperative way for the tripeptide analogue. The results suggest that the presence of good anchoring donors on both sides of the amide groups is responsible for the cooperative deprotonation of the two amide-NH groups. The Royal Society of Chemistry 2005.

In this work the conformational preferences of l-aspartic acid dimethyl ester (AspOMe) and its N-acetylated derivative (AcAspOMe) were evaluated through spectroscopic data and theoretical calculations. Unlike amino acids, their corresponding amino ester derivatives do not exhibit a zwitterionic structure and are soluble in most organic solvents, enabling their studies in these media. Thus, the conformers of AspOMe and AcAspOMe were theoretically determined both in isolated phase and in solution (IEF-PCM model) at the ωB97X-D/aug-cc-pVTZ level. A joint analysis of the experimental and theoretical 3JHH coupling constants in several aprotic solvents allowed assigning the most stable conformers, showing excellent agreement between these approaches. Also, IR spectroscopy allowed us to obtain quantitative data on AcAspOMe conformer populations in different solvents. Natural bond orbital (NBO) analysis indicated that both steric and hyperconjugative contributions count in determining the relative conformer stabilities of these compounds. Intramolecular hydrogen bonding, characterized by Quantum Theory of Atoms in Molecules (QTAIM) and Non-Covalent Interactions (NCI) methodologies, represents only a secondary factor to drive the stabilities of AspOMe and AcAspOMe conformers. This journal is

A series of γ,γ-dimethyl and γ,γ-diphenyl substituted α- and β-amino-butyrolactones have been prepared in enantiomerically pure form using L-aspartic acid as a chiral building block. For the final Grignard reaction the difference in chemical reactivity between the carboxyl groups of aspartic acid was increased or inverted by preparing the corresponding semiesters, diesters and anhydrides. The resulting hydroxyacids and hydroxyesters lactonised in most cases during work up. Thus, (2S)-2-ethoxycarbonylamino-succinic acid-4-methylester 1 reacted with methylmagnesium iodide to form (3S)-3-ethoxycarbonylamino-5,5-dimethyl-tetrahydrofuran-2-one 2b. Two interesting side products were obtained and were found to result from attack at the C-1 carboxylic acid rather than the C-4 carboxylic ester group leading to (3S)-3-ethoxycarbonylamino-4-oxo-pentanoic acid methylester 3 and (4S)-4-ethoxycarbonylamino-5,5-dimethyl-tetrahydrofuran-2-one 5a. Copyright (C) 2000 Elsevier Science Ltd.

Specialized cellular networks of oxidoreductases coordinate the dithiol/disulfide-exchange reactions that control metabolism, protein regulation, and redox homeostasis. For probes to be selective for redox enzymes and effector proteins (nM to μM concentrations), they must also be able to resist non-specific triggering by the ca. 50 mM background of non-catalytic cellular monothiols. However, no such selective reduction-sensing systems have yet been established. Here, we used rational structural design to independently vary thermodynamic and kinetic aspects of disulfide stability, creating a series of unusual disulfide reduction trigger units designed for stability to monothiols. We integrated the motifs into modular series of fluorogenic probes that release and activate an arbitrary chemical cargo upon reduction, and compared their performance to that of the literature-known disulfides. The probes were comprehensively screened for biological stability and selectivity against a range of redox effector proteins and enzymes. This design process delivered the first disulfide probes with excellent stability to monothiols yet high selectivity for the key redox-Active protein effector, thioredoxin. We anticipate that further applications of these novel disulfide triggers will deliver unique probes targeting cellular thioredoxins. We also anticipate that further tuning following this design paradigm will enable redox probes for other important dithiol-manifold redox proteins, that will be useful in revealing the hitherto hidden dynamics of endogenous cellular redox systems.

Achieving a precise control of the final structure of metal-organic frameworks (MOFs) is necessary to obtain desired physical properties. Here, we describe how the use of a metalloligand design strategy and a judicious choice of ligands inspired from nature is a versatile approach to succeed in this challenging task. We report a new porous chiral MOF, with the formula Ca5II{CuII10[(S,S)-aspartamox]5}·160H2O (1), constructed from Cu2+and Ca2+ions and aspartic acid-decorated ligands, where biometal Cu2+ions are bridged by the carboxylate groups of aspartic acid moieties. The structure of MOF1reveals an infinite network of basket-like cages, built by 10 crystallographically distinct Cu(II) metal ions and five aspartamox ligands acting as bricks of a tubular motif, composed of seven basket-like cages each. The pillared hepta-packed cages generate pseudo-rhombohedral nanosized channels of ca. 0.7 and 0.4 nm along thebandacrystallographic axes. This intricate porous 3D network is anionic and chiral, each cage displaying receptor properties toward three-nuclear [Ca3(μ-H2O)4(H2O)17]6+entities. represents the first example of an extended porous structure based on essential biometals Cu2+and Ca2+ions together with aspartic acid as amino acid. shows good biocompatibility, making it a good candidate to be used as a drug carrier, and hydrolyzes in acid water. The hypothesis has been further supported by an adsorption experiment here reported, as a proof-of-principle study, using dopamine hydrochloride as a model drug to follow the encapsulation process. Results validate the potential ability of to act as a drug carrier. Thus, these make this MOF one of the few examples of biocompatible and degradable porous solid carriers for eventual release of drugs in the stomach stimulated by gastric low pH.

Urethane synthesis via oxidative decarboxylation of oxamic acids under mild electrochemical conditions is reported. This simple phosgene-free route to urethanes involves an in situ generation of isocyanates by anodic oxidation of oxamic acids in an alcoholic medium. The reaction is applicable to a wide range of oxamic acids, including chiral ones, and alcohols furnishing the desired urethanes in a one-pot process without the use of a chemical oxidant.

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis (Mtb), each year causing millions of deaths. In this article, we present the synthesis and biological evaluations of new potential antimycobacterial compounds containing a fragment of the first-line antitubercular drug pyrazinamide (PZA), coupled with methyl or ethyl esters of selected amino acids. The antimicrobial activity was evaluated on a variety of (myco)bacterial strains, including Mtb H37Ra, M. smegmatis, M. aurum, Staphylococcus aureus, Pseudomonas aeruginosa, and fungal strains, including Candida albicans and Aspergillus flavus. Emphasis was placed on the comparison of enantiomer activities. None of the synthesized compounds showed any significant activity against fungal strains, and their antibacterial activities were also low, the best minimum inhibitory concentration (MIC) value was 31.25 μM. However, several compounds presented high activity against Mtb. Overall, higher activity was seen in derivatives containing l-amino acids. Similarly, the activity seems tied to the more lipophilic compounds. The most active derivative contained phenylglycine moiety (PC-d/l-Pgl-Me, MIC 1.95 μg/mL). All active compounds possessed low cytotoxicity and good selectivity towards Mtb. To the best of our knowledge, this is the first study comparing the activities of the d- and l-amino acid derivatives of pyrazinamide as potential antimycobacterial compounds.

Malaria is an infectious disease caused by a parasite of the genus Plasmodium, and the emergence of parasites resistant to all current antimalarial drugs highlights the urgency of having new classes of molecules. We developed an effective method for the synthesis of a series of β-modified acyclonucleoside phosphonate (ANP) derivatives, using commercially available and inexpensive materials (i.e., aspartic acid and purine heterocycles). Their biological evaluation in cell culture experiments and SAR revealed that the compounds' effectiveness depends on the presence of a hydroxyl group, the chain length (four carbons), and the nature of the nucleobase (guanine). The most active derivative inhibits the growth of Plasmodium falcIParum in vitro in the nanomolar range (IC50 = 74 nM) with high selectivity index (SI > 1350). This compound also showed remarkable in vivo activity in P. berghei-infected mice (ED50 ～0.5 mg/kg) when administered by the IP route and is, although less efficient, still active via the oral route. It is the first ANP derivative with such potent antimalarial activity and therefore has considerable potential for development as a new antimalarial drug.

Fluorescent sensors are a vital research tool, enabling the study of intricate cellular processes in a sensitive manner. The design and synthesis of responsive and targeted probes is necessary to allow such processes to be interrogated in the cellular environment. This remains a challenge, and requires methods for functionalisation of fluorophores with multiple appendages for sensing and targeting groups. Methods to synthesise more structurally complex derivatives of fluorophores will expand their potential scope. Most known 4-amino-1,8-naphthalimides are only functionalised at imide and 4-positions, and structural modifications at additional positions will increase the breadth of their utility as responsive sensors. In this work, methods for the incorporation of a hypoxia sensing group to 4-amino-1,8-naphthalimide were evaluated. An intermediate was developed that allowed us to incorporate a sensing group, targeting group, and ICT donor to the naphthalimide core in a modular fashion. Synthetic strategies for attaching the hypoxia sensing group and how they affected the fluorescence of the naphthalimide were evaluated by photophysical characterisation and time-dependent density functional theory. An extracellular hypoxia probe was then rationally designed that could selectively image the hypoxic and necrotic region of tumour spheroids. Our results demonstrate the versatility of the naphthalimide scaffold and expand its utility. This approach to probe design will enable the flexible, efficient generation of selective, targeted fluorescent sensors for various biological purposes.

The generation of carbamoyl radicals, followed by their addition to heteroarenes, was performed under mild conditions through a metal-free photocatalyzed decarboxylation of oxamic acids. The process has been applied to the carbamoylation of heteroaromatic bases using α-aminoacid-derived oxamic acids, leading to the corresponding amides without racemization.

The present invention provides: a novel pyrrolo-lactone compound, which can be used as an improved pain therapeutic agent containing various substituents by using glucose and ribose as reducing sugars and conducting a reaction with various kinds of natural and unnatural amino acids; and novel pyrrolo compounds produced during a process of manufacturing the same. The novel pyrrolo-lactone and pyrrole compounds are substances which can be used as improved pain therapeutic agent by having increased restoration ability of glutathione in living cells against reactive oxygen species.COPYRIGHT KIPO 2019

It has been postulated that the KOR affinity depends on the dihedral angle of the ethylenediamine pharmacophore. Herein, 2,5-diazabicyclooctanes bearing a pyrrolidino moiety in the 7-position were envisaged to study KOR agonists with a conformationally rigid ethylenediamine pharmacophore and thus a defined N(pyrrolidine)-C7-C1-N2 dihedral angle. The first approach with an intramolecular addition at the chiral sulfinylimines 9 failed to give bicyclic products. The key step in the second approach was a Dieckmann analogous cyclization providing mixed methyl silyl ketals 11a-e as key intermediates. The highest KOR affinity was found for the 2,5-dibenzyl substituted derivatives (S,R,S)-16a (Ki = 31 nM) and (R,S,R)-16a (Ki = 74 nM) with the pyrrolidine ring oriented towards N-5. The high KOR affinity of (S,R,S)-16a is unexpected, since the KOR pharmacophoric ethylenediamine system adopts a dihedral angle of about 160°, which is quite different from the angle of the energetically most favored conformer of the flexible and potent KOR agonist 2. (S,R,S)-16a represents a KOR agonist with moderate selectivity over MOR (8-fold) and DOR (5-fold), but high selectivity over both σ receptor subtypes. In the [35S]GTPγS assay (S,R,S)-16a reacted as a full KOR agonist with an EC50 value of 240 nM.

The invention discloses a D-asparaginic acid preparation method. The configuration inversion technology is adopted, and the preparation method comprises the steps that L-dimethyl malate-2-besilate can be formed by generating L-dimethyl malate through L-malic acid and then making the L-dimethyl malate react with benzene sulfonyl chloride, then the L-dimethyl malate-2-besilate is made to react with phthalimide potassium, and benzenesulfonic acid serves as a good removal agent, so that D- dimethyl aspartate-2-phthalimide is formed, hydrolysis is conducted under the alkaline condition, D-disodium aspartate is generated, after passing through cation exchange resin, effluent is subjected to concentration, and ethyl alcohol with the concentration being 95% is added for crystallization, so that D-asparaginic acid is obtained. By means of the method, neither high temperature nor high pressure is needed, resolution is not needed, environmental pollution is not caused, and the yield can reach 75% and above.

The invention relates to a preparation method of an optical active compound, represented by formula I, or a hydrochloride of the optical active compound by taking a compound with optical activity as a starting material. Raw materials of the preparation method are cheap and easily available; no splitting is needed; the whole technological operation is simple and convenient; cost is low; pollution on environment is less; and the preparation method is suitable for industrialized production. In the formula I, n is 1 or 2 or 3.

In this study inspired by previous work on 3-substituted Asp analogues, we designed and synthesized a total of 32 β-sulfonamide Asp analogues and characterized their pharmacological properties at the excitatory amino acid transporter subtypes EAAT1, EAAT2, and EAAT3. In addition to several potent EAAT inhibitors displaying IC50 values ～1 μM at all three subtypes, this elaborate structure-activity relationship also identified analogues exhibiting distinct preferences or selectivities for specific transporter subtypes. Introduction of two fluorine atoms on the phenyl ring yielded analogue 4y that displayed an IC50 of 0.8 μM at EAAT1 with a 14- and 9-fold preference over EAAT2 and EAAT3, respectively. Conversely, the m-CF3-phenyl analogue 4r was a potent selective EAAT2-inhibitor (IC50 = 2.8 μM) exhibiting 30- and 50-fold selectivity over EAAT1 and EAAT3, respectively. In conclusion, even small structural differences in these β-sulfonamide Asp analogues provide analogues with diverse EAAT subtype selectivity profiles.

The present invention relates to the field of organic synthesis technology, in particular to a kind of aspartic acid condensate preparation method, the preparation method comprises the following steps : (1) aspartic acid with alcohol to undergo esterification reaction, asparagic acid diester is obtained ; (2) Boc-L-aspartic acid-1-benzyl ester with aspartic acid diester reaction, the condensation product obtained ; (3) hydrolysis of the condensation product, the condensation states the asparagus acid is obtained. The invention uses of aspartic acid and Boc-L-aspartic acid-1-benzyl ester as the raw material, by esterification, condensation, hydrolysis, separation and purification to obtain high-purity aspartic acid condensate. The preparation method is suitable for laboratory in the preparation of large quantities, the impurity removal effect is good in the purification process. (by machine translation)

A convenient approach towards the synthesis of orthogonally protected chiral bis-a-amino acids (OPBAAs) is described. The key transformations include: (1) a highly stereoselective conjugation (alkylation) of the Sch?llkopf bislactim ethers and oxazolidinyl alkyl halides to build a backbone skeleton; and (2) our orthogonal protection strategy. A series of enantiopure OPBAAs bearing a variety of alkyl chain as a spacer; two stereogenic centers; and three protecting groups were prepared as examples. These versatile molecules were applied to the synthesis of biologically interesting di- or tri-peptide analogues, including chiral iE-meso-DAP and A-iE-meso-DAP, for the study of Nod1 activation in the innate immune response.

The first asymmetric total synthesis of the natural pyrrole lactone longanlactone has been achieved. The key reactions, a Barbier propargylation and a Paal-Knorr pyrrole synthesis, have provided easy access to the target natural product from L-aspartic acid in six steps and 31 % overall yield. The C-4 epimer of the natural product and propionyllonganlactone have also been prepared by this strategy.

A series of stable acyclic aminals derived from L-(+)-aspartic acid were synthesized in excellent yields (up to 96%) and characterized by spectroscopic methods. They were applied as enantioselective catalysts in Henry reactions of nitromethane with various aldehydes in the presence of Cu(II) ions, affording the corresponding adducts in high yields (up to 90%) and enantioselectivities (up to 92% ee).

Cyclic peptides containing 5-hydroxytryptophan and thiazole moieties were isolated from the marine sponge Discodermia calyx collected near Shikine-jima Island, Japan. The structures of calyxamides A (1) and B (2), including the absolute configurations of all amino acids, were elucidated by spectroscopic analyses and degradation experiments. The structures are similar to keramamides F and G, previously isolated from Theonella sp. The analysis of the 16S rDNA sequences obtained from the metagenomic DNA of D. calyx revealed the presence of Candidatus Entotheonella sp., an unculturable δ-proteobacterium inhabiting the Theonella genus and implicated in the biosynthesis of bioactive peptides.

A base-mediated 6-endo-trig cyclization of readily accessible enone-derived α-amino acids has been developed for the direct synthesis of novel 2,6-cis-6-substituted-4-oxo-l-pipecolic acids. A range of aliphatic and aryl side chains were tolerated by this mild procedure to give the target compounds in good overall yields. Molecular modeling of the 6-endo-trig cyclization allowed some insight as to how these compounds were formed, with the enolate intermediate generated via an equilibrium process, followed by irreversible tautomerization/neutralization providing the driving force for product formation. Stereoselective reduction and deprotection of the resulting 2,6-cis-6-substituted 4-oxo-l-pipecolic acids to the corresponding 4-hydroxy-l-pipecolic acids was also performed.

Dithiothreitol (DTT) is the standard reagent for reducing disulfide bonds between and within biological molecules. At neutral pH, however, >99% of DTT thiol groups are protonated and thus unreactive. Herein, we report on (2S)-2-amino-1,4-dimercaptobutane (dithiobutylamine or DTBA), a dithiol that can be synthesized from l-aspartic acid in a few high-yielding steps that are amenable to a large-scale process. DTBA has thiol pKa values that are ～1 unit lower than those of DTT and forms a disulfide with a similar E o′ value. DTBA reduces disulfide bonds in both small molecules and proteins faster than does DTT. The amino group of DTBA enables its isolation by cation-exchange and facilitates its conjugation. These attributes indicate that DTBA is a superior reagent for reducing disulfide bonds in aqueous solution.

Starting with the proteinogenic amino acids (S)-aspartate and (S)-glutamate the homologous piperazine-alcanols 3 and 4 were prepared in a five step synthesis. The diversity was introduced by N-1 alkylation of the piperazinediones 5 and 6 with various alkyl halides. Subsequent LiAlH 4 reduction of the dioxopiperazine-esters 7 and 8 provided the alcohols 3 and 4. The ethanol derivatives 3 show similar σ1 affinity as the methanol derivatives 2, but increased selectivity over the σ2 subtype. The corresponding propanol derivatives 4 are considerably less potent. A benzyl or dimethylallyl residue at N-1 appears to be optimal for high σ1 affinity.

A new class of 7-azaindole analogs of MK-7246 as potent and selective CRTH2 antagonists is reported. The SAR leading to the identification of the optimal azaindole regioisomer as well as the pharmacokinetics and off-target activities of the most potent antagonists are disclosed.

In this manuscript we wish to report the discovery of MK-7246 (4), a potent and selective CRTH2 (DP2) antagonist. SAR studies leading to MK-7246 along with two synthetic sequences enabling the preparation of this novel class of CRTH2 antagonist are reported. Finally, the pharmacokinetic and metabolic profile of MK-7246 is disclosed.

Mild and efficient enantioselective Henry reactions of nitromethane with various aldehydes were catalyzed by a novel L-(+)-aspartic acid-derived Schiff base ligand in the presence of Cu(II) ions, affording the corresponding adducts in high yields (up to 96%) and enantioselectivities (up to 92% ee). TUBITAK.

To discover analgesics for treating chronic pain 17 novel Schiff's bases, N,N′-(Z-allylidene-1,3-diyl)bisamino acid methyl esters were prepared from 1,1,3,3,-tetramethoxypropane and amino acid methyl esters. On tail-flick mouse model 20 μmol/kg of these Schiff's bases were orally administered, the analgesic action started 30 min after administration, reached the maximum 120 min after administration, and at 180 min this action was still observed. On a xylene-induced ear edema mouse model 20 μmol/kg of these Schiff's bases exhibited desirable anti-inflammation. Thus the present Schiff's bases are able to treat chronic pain from inflammation. The effect of the side chains of the amino acid residues of these Schiff's bases on the analgesic activity was explained with 3D QSAR.

An N,O-protected, iodinated bishomoalanine derivative, safely available from glutamic acid, reacts with aryl halides in a Negishi reaction in high yields. From the coupling product, Fmoc-protected amino acids with aromatic and heteroaromatic side chains were generated in high yields by racemization-free procedures. These monomers could be used for solid-phase peptide synthesis. Georg Thieme Verlag Stuttgart.

The utility of the tert-butylsulfonyl group (Bus) for the temporary protection of amino acids and peptides is reported. Compatibility and orthogonality in the presence of other N- and O-protecting groups were studied.

A series of (dialkoxyphosphoryl)thioureas and their 1,3,2-oxazaphosphinane analogs containing fragments of glycine, alanine, ss-alanine, L-aspartic and L-glutamic acids, as well as phosphorylureas derived from glycine and ss-alanine were synthesized in the search for potential biologically active compounds (including possible inhibitors of aspartate trans-carbamoylase).

The Kulinkovich cyclopropanation reaction has been used to synthesize azabicyclo[3.1.0]hexanols from amino acid derivatives containing two ester moieties.

A novel method was used to directly convert aliphatic and aromatic primary amides into their corresponding methyl esters in high yields (up to 99 %) under mild reaction conditions. Possible mechanisms were studied at the B3LYP/6-31++G(d,p) level of theory. Formation of the ester proceeded through a rearrangement of the -OMe and -NH2 groups in the RC(O)NHS(O)OMe intermediate in a H+-catalyzed six-membered ring transition state structure. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.

We have developed an efficient and a general approach to chiral 2-substituted N-tosylpiperidines starting from chiral α-substituted-N-tosylaziridines. Using this approach, we have synthesized (+)-coniine. The synthesis of chiral N-tosyl-2-piperidinylethanol 15 and ent-15, was achieved from l- and d-aspartic acids, respectively in few steps. Piperidine 15 was converted into 2-(2-hydroxysubstituted)piperidines of type 2 in optically active form. By applying this strategy, asymmetric syntheses of halosaline (R,R)-2a, (+)- and (-)-sedamine 2b, (+)- and (-)-allosedamine 2c, (+)- and (-)-sedridine 2d, (+)- and (-)-allosedridine 2e, (+)-tetraponerine T-3 3a, T-4 3c, T-7 3b, and T-8 3d have been achieved in high yields. These stereoisomers can be interconverted via Mitsunobu inversion in excellent yields.

A new approach for the stereoselective synthesis of guanidine-derived amino acids, L-arginine and (+)-blastidic acid, has been devised which allows the selective incorporation of isotopic labels in both the side chain of the amino acid as well as the guanidine unit. A new asymmetric synthesis of the (S,R)-diastereomer of reboxetine, an antidepressant, has also been completed which allows the specific incorporation of radiolabelled iodine for SPECT imaging. Copyright

Facile methods are described for accessing four diastereomerically pure 3-mercaptoaspartic acid derivative from l-aspartic acid. In our synthesis, ring-opening reactions of oxazoline-4,5-dicarboxylate with thiolacetic acid as well as the stereochemical interconversion of both α- and β-configuration via oxazoline chemistry were utilized as key steps.

A versatile, fully automated flow hydrogenator has been developed that is able to perform sequential flow optimisation experiments, flow library hydrogenation, or iterative scale-up hydrogenation. The behaviour of a palladium catalyst in effecting removal of O-benzyl and N-benzyloxycarbonyl protecting groups has been investigated. Significant observations relating to maintaining optimal throughput are reported. A small library of peptidic derivatives has been deprotected in high yield and purity.

A class of 5-trifluoroacetylamino-1,3-dioxacycloalkanes, 5-benzoylamino-1,3-dioxacycloalkanes, and 5-amino-1,3-dioxacycloalkane compounds were stereoselectively synthesized as potential anti-inflammatory drug candidates. The anti-inflammatory activities of these compounds were tested using the xylene-induced mouse ear edema model, from which multiple compounds possessing anti-inflammatory properties which surpass aspirin were identified; these compounds were then compared to establish structure-activity relationships.

(Chemical Equation Presented). In this paper we describe the stereoselective synthesis of functionalized lactam 7 via two enantiospecific piperidine-forming techniques and its employment in a general synthetic approach to Nuphar alkaloids. Specifically, the formation of piperidine 18 by formal [3 + 3] cycloaddition and stepwise annelation processes is described; the latter technique was found to be significantly more efficient than the Pd-catalyzed TMM addition process. Finally, exploitation of the exocyclic alkene installed in the piperidine-forming reaction in the transformation of 18 to (-)-deoxynupharidine ((-)-2), (-)-castoramine ((-)-3), and (-)-nupharolutine ((-)-4) via intermediate lactam 7 is delineated.

The present application describes sulfonylaminovalerolactams and derivatives thereof of Formula Ia-If: or pharmaceutically acceptable salt forms thereof, wherein ring G is a mono- or bicyclic carbocycle or heterocycle. Compounds of the present invention are useful as inhibitors of trypsin-like serine proteases, specifically factor Xa.

Reaction of N-Boc amino acids with ceric ammonium nitrate in an alcohol as the solvent at room temperature resulted in the esterification of N-Boc amino acids with Boc group retention. When the reaction was conducted at reflux temperature, esterification was accompanied with simultaneous removal of the Boc group. Both reactions gave the desired products in good yields.

The consecutive treatment of N-Cbz amino protected compounds with LiHMDS and CbzCl provides a practical method for the preparation of N,N-benzyloxycarbamoyl (N,N-di-Cbz) derivatives in good yield. When α-amino acids are used the protection occurs without racemization. The method is compatible with a wide range of other functional and protecting groups. The procedure is also valid for the synthesis of mixed N,N-carbamoyl derivatives.

A simple and efficient synthesis of L-arginine has been achieved in 12 steps and 24% overall yield. Regioselective reduction and functional group manipulation of the β-side chain of aspartic acid allowed the preparation of an ornithine derivative, which was then guanylated with a bis-protected 1-guanyl-pyrazole and deprotected to give L-arginine. This approach allows the flexible incorporation of stable isotopes and this is demonstrated using potassium 13C-cyanide, which has resulted in the preparation of 5-13C-L-arginine.

(Equation presented) A stereocontrolled route to Nuphar alkaloids is described that employs a formal [3 + 3] cycloaddition strategy to assemble the piperidine nucleus. The addition of Pd-TMM complexes to aziridine 10 was found to be sluggish; however, the addition of a functionalized allyl Grignard reagent followed by a Mitsunobu condensation reaction provided 11 in high yield. The employment of this route in the formal synthesis of (-)-deoxynupharidine 1 is described.

A synthetic route to thymine derivatives of (2S,3R)- and (2S,3S)-4-hydroxyvaline has been developed starting from commercially available L-aspartic acid.

The kinetic resolution of malic and aspartic acid diesters as well as of its N-butanoyl dimethyl ester by highly regioselective lipases and acylase I enzymes were studied. Candida antarctica lipase A on Celite catalyzed the enantioselective acylation of the hydroxyl and amino groups. Acylase I from Aspergillus melleus and Candida antarctica lipase B catalyzed the enantioselective alcoholyses of the ester groups at the α- and β-positions, respectively. (C) 1999 Elsevier Science Ltd.

Enantiomerically pure 3-amino cyclic amines such as 3-amino pyrrolidine, 3-amino piperidine, and 2,3,4,5,6,7-hexahydro-1H-azepine have been synthesized in high yields from the optically active natural α-amino acids such as L-aspartic acid, L-glutamic acid, L-2-aminoadipic acid, and their enantiomers.

A hydrolytically stable analogue of the Tn antigen has been efficiently synthesized for the first time employing a SmI2-promoted coupling of the pyridyl sulfone of N-acetylgalactosamine with an aldehydoamino acid derivative.

The enantiospecific synthesis of unnatural unsaturated and saturated α- amino acids based on a Wittig type reaction is described. The versatile synthetic intermediates, L-glutamic and L-aspartic acid semialdehydes, are obtained from the corresponding N,N-di-Boc-diesters, by the selective reduction of the ω-ester with DIBAL under controlled conditions. The semialdehydes are chemically stable for a prolonged time and react with various phosphorous ylides, under controlled conditions, to produce the enantiomerically pure unsaturated α-amino acids in high yields. The method is equally applicable to homologated diesters obtained by the presented methodology providing unsaturated amino acids with variable unsaturated- positions and geometries. The corresponding saturated products can be obtained by simple hydrogenation.

A method for preparing an amino acid ester with sulfuric acid as the catalyst in high yield, in which a mixture of amino acid, sulfuric acid and an alcohol is heated while adding the alcohol as a liquid or gas to the reaction mixture and alcohol from the reaction mixture is distilled off.

Nucleophilic additions to chiral amino lactols obtained from L-aspartic acid containing a chiral α-silyloxymethyl function by simple Grignard reagents exhibited high stereoselectivity to provide the corresponding optically active amino alcohols containing three contiguous stereogenic centers. The mechanistic origin of the asymmetric induction is rationalized based on chelation controlled models.