- n-Pentyl N-acetylprolinate. A new skin penetration enhancer
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The activity of n-pentyl N-acetylprolinate (PNAP) as a transdermal penetration enhancer was investigated. PNAP was synthesized from L-proline by acetylation with acetic anhydride, followed by acid-catalyzed esterification with 1-pentanol. Structure confirmation was accomplished by IR and NMR spectroscopy and elemental analysis. Benzoic acid (BA) was used as a model drug, and the effect of PNAP on the flux of BA through human cadaver skin was evaluated. The central nervous system (CNS) toxicity of PNAP was evaluated by comparing the effects of intraperitoneal administration of PNAP to mice with those of laurocapram (Azone), a known penetration enhancer. Based on preliminary studies, PNAP appears to be an effective transdermal penetration enhancer, is nontoxic at tow doses, and exhibits dose-related CNS toxicity at higher doses.
- Harris,Tenjarla,Holbrook,Smith,Mead,Entrekin
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Read Online
- Bacterial Alkaloids Prevent Amoebal Predation
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Bacterial defense mechanisms have evolved to protect bacteria against predation by nematodes, predatory bacteria, or amoebae. We identified novel bacterial alkaloids (pyreudiones A–D) that protect the producer, Pseudomonas fluorescens HKI0770, against amoebal predation. Isolation, structure elucidation, total synthesis, and a proposed biosynthetic pathway for these structures are presented. The generation of P. fluorescens gene-deletion mutants unable to produce pyreudiones rendered the bacterium edible to a variety of soil-dwelling amoebae.
- Klapper, Martin,G?tze, Sebastian,Barnett, Robert,Willing, Karsten,Stallforth, Pierre
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Read Online
- Bioinspired Synthesis of (?)-PF-1018
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The combination of electrocyclizations and cycloadditions accounts for the formation of a range of fascinating natural products. Cascades consisting of 8π electrocyclizations followed by a 6π electrocyclization and a cycloaddition are relatively common. We now report the synthesis of the tetramic acid PF-1018 through an 8π electrocyclization, the product of which is immediately intercepted by a Diels–Alder cycloaddition. The success of this pericyclic cascade was critically dependent on the substitution pattern of the starting polyene and could be rationalized through DFT calculations. The completion of the synthesis required the instalment of a trisubstituted double bond by radical deoxygenation. An unexpected side product formed through 4-exo-trig radical cyclization could be recycled through an unprecedented triflation/fragmentation.
- Houk, K. N.,Jamieson, Cooper S.,Quintela-Varela, Hugo,Shao, Qianzhen,Trauner, Dirk
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supporting information
p. 5263 - 5267
(2020/02/11)
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- The effect of imidazolium salts with amino acids as counterions on the reactivity of 4-nitrophenyl acetate: A kinetic study
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As a first approach to improve the “green character” of the surfactants based on imidazolium cations, three surfactants using 1-tetradecyl-3-methylimidazolium [C14mim]+ as cation and different amino acids (AA) as counterion, were syn
- Figueroa, Roberto,Orth, Elisa,Pavez, Paulina,Rojas, Mabel,Santos, José G.
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- (4-HYDROXYPYRROLIDIN-2-YL)-HETEROCYCLIC COMPOUNDS AND METHODS OF USE THEREOF
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The present disclosure relates to bifunctional compounds of formula (I), which can be used as modulators of targeted ubiquitination. In particular, the present disclosure is directed to compounds which contain on one end a VHL ligand moiety, which binds to the VHL E3 ubiquitin ligase, and on the other end a moiety that binds a target protein such that degradation of the target protein/polypeptide is effectuated. Also disclosed are VHL ligands of formula (III).
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Paragraph 0710; 0711; 0712
(2019/05/15)
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- Synthesis method of L-prolinamide
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The invention belongs to the field of organic synthesis, and discloses a synthesis method of L-prolinamide. The method comprises steps of S1, dissolving an initial material, L-proline, in water and then reacting with acetic anhydride, after reaction, extracting and drying to prepare N-acetyl-L-proline; S2, in a solvent system, performing a reaction on a raw material, N-acetyl-L-proline prepared inS1 and thionyl chloride, then concentrating and drying to obtain a compound; S3, dripping aqueous ammonia in the compound prepared in S2 as a raw material so as to react, filtering and preparing 1-acetyl-2-pyrrolidinecarboxamide; and S4, dripping HC1 into the 1-acetyl-2-pyrrolidinecarboxamide prepared in S3 as a raw material, so as to react, then concentrating, filtering and drying to prepare L-prolinamide. In the reaction process of the synthesis method provided by the invention, common reagent raw materials are used, the costs are low, the reaction conditions are mild, the chiral purity ishigh, the yield is high, the environment pressure is low, and the synthesis method is suitable for large-scale production.
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Paragraph 0030; 0031; 0035; 0036; 0040; 0041; 0045; 0046
(2019/01/16)
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- Reactivity of α-Amino Acids in the Reaction with Esters in Aqueous–1,4-Dioxane Media
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The kinetics of the reaction of a series of α-amino acids with 4-nitrophenyl acetate, 4-nitrophenyl benzoate, and 2,4,6-trinitrophenyl benzoate in aqueous 1,4-dioxane medium has been studied. Kinetics of the reactions involving 4-nitrophenyl acetate and 2,4,6-trinitrophenyl benzoate has complied with the Br?nsted dependence and revealed linear correlation between rate constant logarithm and the energy difference of the frontier orbitals of α-amino acids anions.
- Kochetova,Kustova,Kuritsyn
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- Cinnamic acid derivative with aldose reductase inhibitory activity as well as preparation method and application thereof
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The invention discloses a cinnamic acid derivative with aldose reductase inhibitory activity, a preparation method thereof and an application of the cinnamic acid derivative in preparation of a medicine used for treating diabetic complications and diseases caused by oxidative stress. The structure of the compound is shown in a formula I. The preparation method comprises the following steps: firstly reacting substituted benzaldehyde with substituted acetic acid or acid anhydride thereof to obtain substituted cinnamic acid, then reacting with a diamine compound protected by N-tertiary butoxy acyl to obtain substituted cinnamoyl diamide protected by N-tertiary butoxy acyl; and carrying out tertiary butoxy acyl deprotection on the substituted cinnamoyl diamide protected by N-tertiary butoxy acyl, and then reacting with natural or non-natural N-acyl alpha-amino acid, so that the cinnamic acid derivative is obtained. The cinnamic acid derivative compound disclosed by the invention has excellent inhibitory activity on aldose reductase and excellent antioxidant activity and can be applied to preparation of a medicine used for treating the diabetic complications, especially diabetic retinopathy, senile dementia due to diabetes and nerve ending disturbance, as well as diseases caused by the oxidative stress.
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Paragraph 0087; 0091
(2017/09/01)
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- Modulating hydrogen-bond basicity within the context of protein-ligand binding: A case study with thrombin inhibitors that?reveals a dominating role for desolvation
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Understanding subtle aspects of hydrogen bonding is a challenging but crucial task to improve our ability to design ligands with high affinity for protein hosts. To gain a deeper understanding of these aspects, we investigated a series of thrombin inhibitors in which the basicity of the ligand's group that accepts an H-bond from Gly216 was modulated via bioisosterism; e.g., a C=O acceptor was made electron deficient or rich via bioisosteric replacements of the adjacent moiety. Although the ligand's binding affinity was anticipated to improve when the H-bond basicity is increased (due to stronger H-bonding with the protein), we herein present data that unexpectedly revealed an opposite trend. This trend was attributed to a dominating role played by desolvation in determining the relative binding affinity. For example, a decrease in the H-bond basicity reduces the desolvation penalty and, as experimentally observed, improves the binding affinity, given that the reduction in the desolvation penalty dominates the change in the net contribution of the ligand's interactions with the protein. The current study, therefore, reveals that desolvation can be a major underlying cause for the apparently counterintuitive structure-activity relationship (SAR) outcomes, and indicates that understanding this factor can improve our ability to predict binding affinity and to design more potent ligands.
- Nasief, Nader N.,Said, Ahmed M.,Hangauer, David
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p. 975 - 991
(2016/11/11)
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- Energetic contribution to both acidity and conformational stability in peptide models
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The acidity of N-acyl amino acids is dependent upon the rotameric state of the amide bond. In this work we systematically investigated the acidity difference of the rotamers (ΔpKa) in the frames of various acetylated amino acids. Our results indicated a mutual interaction of two carbonyl groups of an attractive type. We observed conservative ΔpKas for acyclic amino acids (2.2-3.0 kJ mol-1), whereas in the case of alicyclic amino acids, the experimental values revealed a strong dependency on the structural context (1.5-4.4 kJ mol-1). In homologous amino acids (α-, β-, γ-, etc.), the strength of the attraction decays in an exponential fashion. Furthermore, the interaction can accumulate through a chain of amide bonds in a cascade fashion, as demonstrated by an Ac-Pro-Pro dipeptide. As a result, we demonstrate that ΔpKa is an experimental parameter to estimate increments in the carbonyl-carbonyl alignment, as determined by the amino acid or peptidyl context. This parameter is also important in understanding the roles of amino acids in both protein folding and translation in biological systems as well as their evolutionary appearance in the genetic code.
- Kubyshkin, Vladimir,Durkin, Patrick,Budisa, Nediljko
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supporting information
p. 5209 - 5220
(2016/07/06)
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- Peptide Tyrosinase Activators
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Peptides that increase melanin synthesis are provided. These peptides include pentapeptides YSSWY, YRSRK, and their variants. The peptides may activate the enzymatic activity of tyrosinase to increase melanin synthesis. The pharmaceutical, cosmetic, and other compositions including the peptides are also provided. The methods of increasing melanin production in epidermis of a subject are provided where the methods include administering compositions comprising an amount of one or more peptides effective to increase the melanin production. The methods also include treating vitiligo or other hypopigmentation disorders with compositions including one or more peptides.
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- 1 -(CYCLOPENT-2-EN-1 -YL)-3-(2-HYDROXY-3-(ARYLSULFONYL)PHENYL)UREA DERIVATIVES AS CXCR2 INHIBITORS
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The invention relates to 1-(3-sulfonylphenyl)-3-(cyclopent-2-en-1-yl)urea derivatives, and their use in treating or preventing diseases and conditions mediated by the CXCR2 receptor. In addition, the invention relates to compositions containing the derivatives and processes for their preparation.
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Page/Page column 83
(2015/12/18)
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- Organocatalyzed Baylis-Hillman reaction: An enantioselective approach
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A convenient protocol has been developed for the synthesis of Baylis-Hillman adducts in the presence of a base and an organocatalyst. We have designed and synthesized organocatalysts based on hydrogen bonding using a pyrrolidine ring as the backbone and applied them to Baylis-Hillman transformations. This method provides products in good to high yields (73-90%) and with excellent enantiomeric excesses (up to 96%) and reasonable reaction times.
- Thorat, Prashant B.,Goswami, Santosh V.,Khade, Bhimrao C.,Bhusare, Sudhakar R.
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p. 1320 - 1325
(2012/11/06)
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- Recognition of achiral and chiral ammonium salts by neutral ditopic receptors based on chiral salen-UO2 macrocycles
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(Figure Presented) A mononuclear (M20) and a dinuclear (M40) uranyl chiral macrocyclic complex, incorporating both a salen unit containing two phenyl rings linked to a chiral diimine bridge and the (R)-BINOL unit, behaves as an efficient ditopic receptor for achiral and chiral quaternary ammonium salts. Binding affinities in chloroform solution have been measured for 1:1 complexes of many quaternary salts encompassing tetramethylammonium (TMA), tetraethylammonium (TEA), tetrabutylammonium (TBA), and acetylcholine (ACh), as well as trimethylanilinium (TriMAn), benzyltrimethylammonium (BnTriMA), (a-methylbenzyl)trimethylammonium and pyrrolidinium cations. The anion of the salt is bound by the hard Lewis acidic uranyl site, with an increasing binding efficiency on increasing the anion hardness (I- - -), whereas CH-π or π-π attractions by binapthyl moiety, or the salicylaldehyde unit, or the phenyl rings of diimine bridge ensure the recognition of the cation partner. Optimized structures of receptor-anion-cation ternary complexes obtained by MM calculations are supported by 2D-ROESY NMR measurements.
- Amato, Maria E.,Ballistreri, Francesco P.,Gentile, Salvatore,Pappalardo, Andrea,Tomaselli, Gaetano A.,Toscano, Rosa M.
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supporting information; experimental part
p. 1437 - 1443
(2010/06/11)
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- Enhancement of hydrophobic interactions and hydrogen bond strength by cooperativity: Synthesis, modeling, and molecular dynamics simulations of a congeneric series of thrombin inhibitors
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Accurately predicting the binding affinity of ligands to their receptors by computational methods is one of the major challenges in structure-based drug design. One of the potentially significant errors in these predictions is the common assumption that the ligand binding affinity contributions of noncovalent interactions are additive. Herein we present data obtained from two separate series of thrombin inhibitors containing hydrophobic side chains of increasing size that bind in the S3 pocket and with, or without, an adjacent amine that engages in a hydrogen bond with Gly 216. The first series of inhibitors has a m-chlorobenzyl moiety binding in the S1 pocket, and the second has a benzamidine moiety. When the adjacent hydrogen bond is present, the enhanced binding affinity per ?2 of hydrophobic contact surface in the S3 pocket improves by 75% and 59%, respectively, over the inhibitors lacking this hydrogen bond. This improvement of the binding affinity per ?2 demonstrates cooperativity between the hydrophobic interaction and the hydrogen bond.
- Muley, Laveena,Baum, Bernhard,Smolinski, Michael,Freindorf, Marek,Heine, Andreas,Klebe, Gerhard,Hangauer, David G.
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supporting information; experimental part
p. 2126 - 2135
(2010/08/19)
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- A simple method for the alkaline hydrolysis of esters
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A very mild and rapid procedure for the efficient alkaline hydrolysis of esters in non-aqueous conditions has been developed, by the use of dichloromethane/methanol (9:1) as solvent. This method conveniently provides both carboxylic acids and alcohols from the corresponding esters and sodium hydroxide in a few minutes at room temperature. A plausible reaction mechanism is proposed.
- Theodorou, Vassiliki,Skobridis, Konstantinos,Tzakos, Andreas G.,Ragoussis, Valentine
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p. 8230 - 8233
(2008/03/14)
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- Novel series of highly potent non-peptide growth hormone secretagogues with improved bioavailability
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The discovery and the SAR of acylproline derivatives as highly potent growth hormone secretagogues (GHSs) with good oral bioavailability are described. One representative compound, N-[3-(2,2-dimethylpropylamino)-2-hydroxypropyl]-2(R)-[1-(2,2-dimethylpropionyl)pyrrolidine-2(S)- carbonylamino]-3-naphthalen-2-ylpropionamide (4e), showed potent GHS activity (ED50=1 nM) and good oral bioavailability (BA=33.2%). Moreover, the optically pure N-[3-(2,2-dimethylpropylamino)-2(S)-hydroypropyl]-2(R)-[1-(2,2-dimethylpropionyl)pyrrolidine-2(S)-carbonylamino]-3-naphthalen-2- ylpropionamide ((2S)-4e) showed a good metabolic stability against in vitro clearance (human liver microsome) with potent GHS activity.
- Ishige, Hirohide,Ishiyama, Nobuo,Mimura, Mitsuo,Hayashida, Mitsuo,Okuno, Tadashi,Ukai, Kiyoharu,Kiyofuji, Takeshi,Yoneda, Yasuo,Tauchi, Shinji,Aoyama, Akinori,Inoguchi, Kiyoshi
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p. 561 - 566
(2007/10/03)
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- Preparation of both enantiomers of 1-allyl-1,2,3,4-tetrahydro-β-carboline using allyltin reagents and a chiral auxiliary derived from L-proline
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β-Carboline, which had an acyl group derived from L-proline at the 9-position, reacted with allyltributyltin and 2,2,2-trichloroethyl chloroformate to afford an 1-allyl-1,2-dihydro-β-carboline derivative in a diastereoselective manner. The chiral acyl group at N-9 was readily eliminated by aqueous alkali to give a corresponding carboxylic acid. The formed 1-allyl-1,2-dihydro-β-carboline was transformed via two reduction steps to 1-allyl-1,2,3,4-tetrahydro-β-carboline in high ee. When the allylation was carried out using tetraallyltin instead of allyltributyltin, the stereoselectivity was reversed, and the antipode of the allyl adduct was obtained in high yield and ee in the presence of tin(IV) tetraiodide. Thus, it was found that both enantiomers of 1-allyl-β-carboline were obtained in good enantioselectivities by the use of the same chiral auxiliary.
- Itoh, Takashi,Matsuya, Y?ji,Enomoto, Yasuko,Ohsawa, Akio
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p. 7277 - 7289
(2007/10/03)
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- One pot synthesis of novel 5,11-dioxo-6-methyl-5,9,10,11-tetrahydro-8H- naphth[2,3:1,2]pyrrolizine and its 9-acetoxy analogue
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5,11-Dioxo-6-methyl-5,9,10,11-tetrahydro-8H-naphth[2,3:1,2]pyrrolizine 5a and its 9-acetoxy 5b are prepared in a one-flask procedure by the reaction of L-proline 1a or 4-hydroxy-L-proline 1b with refluxing acetic anhydride and olefinic dipolarophile 1,4-naphthoquinone 4.
- Gadaginamath,Kavali,Patil,Shyadligeri
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p. 1123 - 1125
(2007/10/03)
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- Cosmetic composition
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A composition suitable for topical application to mammalian skin and hair for inducing, maintaining or increasing hair growth comprises a hair growth promoter chosen from glutamine derivatives and salts thereof. The composition preferably also comprises an activity enhancer which may be chosen from hair growth stimulants, penetration enhancers and cationic polymers.
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- Structure-activity relationships of the didemnins
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Bioactivities of 42 didemnin congeners, either isolated from the marine tunicates Trididemnun solidum and Aplidium albicans or prepared synthetically and semisynthetically, have been compared. The growth inhibition of various murine and human tumor cells and plaque reduction of HSV-1 and VSV grown on cultured mammalian cells were used to assess cytotoxicity and antiviral activity. Biochemical assays for macromolecular synthesis (protein, DNA, and RNA) and enzyme inhibition (dihydrofolate reductase, thymidylate synthase, DNA polymerase, RNA polymerase, and topoisomerases I and II) were also performed to specify the mechanisms of action of each analogue. Immunosuppressive activity of the didemnins was determined using a mixed lymphocyte reaction (MLR) assay. These assays revealed that the native cyclic depsipeptide core is an essential structural requirement for most of the bioactivites of the didemnins, especially for cytotoxicities and antiviral activities. The linear side-chain portion of the peptide can be altered with a gain, in some cases, of bioactivities. In particular, dehydrodidemnin B, tested against several types of tumor cells and in in vivo studies in mice, as well as didemnin M, tested for the mixed lymphocyte reaction and graft vs host reaction in murine systems, showed remarkable gains in their in vitro and in vivo activities compared to didemnin B.
- Sakai, Ryuichi,Rinehart, Kenneth L.,Kishore, Vimal,Kundu, Bijoy,Faircloth, Glynn,Gloer, James B.,Carney, John R.,Namikoshi, Michio,Sun, Furong,Hughes Jr., Robert G.,Grávalos, Dolores García,De Quesada, Teresa García,Wilson, George R.,Heid, Richard M.
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p. 2819 - 2834
(2007/10/03)
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- Pharmaceutical compositions containing didemnins
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This invention is directed to didemnin derivatives, including N-acyl congeners of didemnin A (DA); several DDB-type analogues of DA in which either pyruvic acid has been replaced (with phenylpyruvic acid or alphaketobutyric acid) or proline at position 8 has been replaced [with L-azetidine-2-carboxylic acid (AZT), L-pipecolic acid (Pip), 1-amino-1-carboxylic cyclopentane (acc 5), D-Pro or sarcosine (sar); and other cyclic depsipeptides related to the didemnins, which were isolated from a relatively polar extract of the tunicate T. solidum; namely the didemnins--X [(R)-3-hydroxy-decanoyl-(Gln) 3 -Lac-Pro didemnin A]; Y [(R)-3-hydroxy-decanoyl-(Gln) 4 -Lac-Pro didemnin A]; M (pGlu-Gln-Lac-Pro-didemnin A); N ([Tyr 5 ] didemnin B); nordidemnin N ([Tyr 5 ] nordidemnin B); and epididemnin A ([2S,4R-Hip 2 ] didemnin A).
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- Cosmetic composition containing DOPA derivatives
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A composition for topical application to human hair or skin contains a chemical analogue of dihydroxyphenyl alanine (DOPA). This chemical analogue can be absorbed by skin or by a hair follicle and metabolised in-vivo, thus leading to the formation of melanin in skin or to the growth of melanin-pigmented hair. Consequently the composition can give controlled skin darkening to mimic sun-induced tanning or can bring about the growth of dar hair in place of the grey or white hair.
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- Vinyl carboxylate an acylating reagent for selective acylation of amines and diols
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Vinyl group of vinyl alkylate (C=2 or 16) and vinyl benzoate have been found to be a good leaving group in acylation of alcohols (40-50% yield) and amines (in 60-90% yield).
- Chen,Chen,Chen,Wang
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p. 3583 - 3584
(2007/10/02)
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- Cosmestic composition
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A composition suitable for topical application to mammalian skin and hair for inducing, maintaining or increasing hair growth comprises a hair growth promoter chosen from glutamic acid derivatives and salts thereof. The composition preferably also comprises an activity enhancer which may be chosen from hair growth stimulants, penetration enhancers and cationic polymers.
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- Hair growth composition containing citric acid esters
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Triesters of citric acid are used for inducing, maintaining or increasing hair growth. Compositions for topical application to mammalian hair or scalp comprise an effective amount of from 1% to 99% by weight of an ester of citric acid having the structure (1): where, R1, R2 and R3 each independently represent a branched or unbranched alkyl, alkenyl, aryl, alkylaryl or arylalkyl group, each said group having from 1 to 18 carbon atoms, R4 represents -H, or a branched or unbranched saturated or unsaturated acyl, alkyl, aryl, alkylaryl or aylalkyl group having from 1 to 18 carbon atoms, in the presence of a cosmetically acceptable vehicle for the citric acid ester and in the absence of solid absorbent for the ester;, said effective amount of said ester being sufficient to increase hair growth in the rat, when said composition is applied topically thereto over a period of no more than three months, by at least 10% more than that obtainable using a control composition from which the said ester has been omitted, in accordance with the Rat Hair Growth Test.
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- Acetylation under ultrasonic conditions: Convenient preparation of N-acetylamino acids
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An efficient and simple method of preparation of acetylamino acids from amino acids under ultrasonic conditions is described. The reactions proceed without racemization and the yields are almost quantitative.
- Veera Reddy,Ravindranath
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p. 257 - 264
(2007/10/02)
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- MOLECULAR RECOGNITION: DIRECTED HYDROGEN BONDING RECEPTORS FOR ACYLAMINO ACID CARBOXYLATES
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A new series of receptors for acylamino acid carboxylates has been synthesized and shown to have increased binding affinity for the substrate as the number of hydrogen bonding groups in the cavity increases.
- Vicent, Cristina,Fan, Erkang,Hamilton, Andrew D.
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p. 4269 - 4272
(2007/10/02)
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- Cosmetic composition
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A composition suitable for topical application to mammalian skin and hair for inducing, maintaining or increasing hair growth comprises a hair growth promoter chosen from N-acylated amino-acids, in which the acyl group has from 2 to 20 carbon atoms, together with a cosmetically acceptable vehicle for the hair growth promoter.
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- Decomposition of N-Nitrosopeptides in Strong Acids
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Decomposition of the N-nitrosodipeptides obtained from N-(N'-acetyl-L-prolyl)glycine and N-(N'-acetyl-L-prolyl)-L-alanine in aqueous acid at 25 deg C involves both deamination and denitrosation.Both reactions occur concurrently via different conjugate acid intermediates, with denitrosation being predominant at high acidity.Acidity dependences and inverse solvent deuterium isotope effects suggest that deamination involves rate limiting attack by H2O on an O-conjugate acid, formed in a rapid pre-equilibrium.For denitrosation, H+ transfer to the amide N-atom is considered rate limiting because of the substantial normal solvent deuterium isotope effects and Bunnett ω values in the range -0.1 to -0.5: the N-conjugate acid formed breaks down rapidly to products.Both the kinetics and mechanisms for decomposition of these N-nitrosodipeptides are very similar to those of alicyclic N-nitrosamides.
- Challis, Brian C.,Milligan, Jamie R.,Mitchell, Robert C.
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p. 1595 - 1600
(2007/10/02)
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- Synthesis and Characterisation of Some New N-Nitrosodipeptides
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The synthesis of 11 new N-nitrosodipeptides by aprotic nitrosation with N2O4 is desdribed for N-(N'-acetyl-L-prolyl)glycine, -L-alanine, -L-phenylalanine; and N-phthalimidoacetylglycine peptides and their (benzyl or ethyl) esters.The UV-vis, IR, 1H NMR and MS properties of the new N-nitrosodipeptides are reported and their structural significance is analysed.
- Challis, Brian C.,Milligan, Jamie R.,Mitchell, Robert C.
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p. 3103 - 3108
(2007/10/02)
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- Synthesis and Stability of N-Nitrosodipeptides
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The synthesis, characterization, and chemical properties of the N-nitroso derivatives of some N-(N-acetylprolyl)-peptides are described.
- Challis, Brian C.,Milligan, James R.,Mitchell, Robert C.
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p. 1050 - 1051
(2007/10/02)
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- Syntheses of Substituted L- and D-Tryptophans
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Several 5-substituted nb-methoxycarbonyl-L- and -D-tryptophan derivatives were synthesized from proline by a new route involving electrochemical oxidation, as well as by the known procedures.Removal of the Nb-methoxycarbonyl group was accomplished by treatment with Me3SiI in refluxing chloroform, then alkaline hydrolysis of the methyl esters afforded 5-substituted L- and D-tryptophans with high optical purities.Keywords - L-tryptophan 5-substituted; D-tryptophan 5-substituted; anodic oxidation; N-methoxycarbonyl group deprotection; Fischer indole synthesis; iodotrimethylsilane
- Irie, Kunihiko,Ishida, Akihiko,Nakamura, Tohru,Oh-ishi, Tokuro
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p. 2126 - 2139
(2007/10/02)
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- Immune-stimulating and cancerostatic 1-acyl-2-cyanoaziridines
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1-Acyl-2-cyanoaziridines of the formula STR1 wherein R is an acyl radical of a carboxylic, sulphonic, sulphinic, sulphenic, phosphonic or phosphoric acid, exhibit immune-stimulating and cancerostatic activities.
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