- Evaluation of Amino Nitriles and an Amino Imidate as Organo?-catalysts in Aldol Reactions
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The efficiency of l -valine and l -proline nitriles and a tert -butyl?- l -proline imidate as organocatalysts for the aldol reaction have been evaluated. l -Valine nitrile was found to be a syn -selective catalyst, while l -proline nitrile was found to be anti -selective, and gave products in modest to good enantioselectivities. tert -Butyl l -proline imidate was found to be a very efficient catalyst in terms of conversion of starting reagents to products, and gave good anti -selectivity. The enantioselectivity of the tert -butyl l -proline imidate was found to be good to excellent, with products being formed in up to 94percent enantiomeric excess.
- Brown, Alexander J.,Clarke, Paul A.,Vagkidis, Nikolaos
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p. 4106 - 4112
(2019/10/28)
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- FUMAGILLOL COMPOUNDS AND METHODS OF MAKING AND USING SAME
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Disclosed herein, in part, are fumagillol compounds and methods of use in treating medical disorders, such as obesity. Pharmaceutical compositions and methods of making fumagillol compounds are provided. The compounds are contemplated to have activity against methionyl aminopeptidase 2.
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Paragraph 00158
(2018/03/06)
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- Amidation of carboxylic acids via the mixed carbonic carboxylic anhydrides and its application to synthesis of antidepressant (1S,2R)-tranylcypromine
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Primary amidations of carboxylic acids 1 or 3 with NH4Cl in the presence of ClCO2Et and Et3N were developed to afford the corresponding primary amides in 22% to quantitative yields. Additionally, we have applied the amidation to the preparation of various amides containing hydroxamic acids and achieved the synthesis of (1S,2R)-tranylcypromine as an antidepressant medicine via Lossen rearrangement.
- Ezawa, Tetsuya,Kawashima, Yuya,Noguchi, Takuya,Jung, Seunghee,Imai, Nobuyuki
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p. 1690 - 1699
(2017/11/14)
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- Prebiotic synthesis of 2-deoxy-d-ribose from interstellar building blocks promoted by amino esters or amino nitriles
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Understanding the prebiotic genesis of 2-deoxy-d-ribose, which forms the backbone of DNA, is of crucial importance to unravelling the origins of life, yet remains open to debate. Here we demonstrate that 20 mol% of proteinogenic amino esters promote the selective formation of 2-deoxy-d-ribose over 2-deoxy-d-threopentose in combined yields of ≥4%. We also demonstrate the first aldol reaction promoted by prebiotically-relevant proteinogenic amino nitriles (20 mol%) for the enantioselective synthesis of d-glyceraldehyde with 6% ee, and its subsequent conversion into 2-deoxy-d-ribose in yields of ≥ 5%. Finally, we explore the combination of these two steps in a one-pot process using 20 mol% of an amino ester or amino nitrile promoter. It is hence demonstrated that three interstellar starting materials, when mixed together with an appropriate promoter, can directly lead to the formation of a mixture of higher carbohydrates, including 2-deoxy-d-ribose.
- Steer, Andrew M.,Bia, Nicolas,Smith, David K.,Clarke, Paul A.
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supporting information
p. 10362 - 10365
(2017/09/25)
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- PEPTIDOMIMETIC COMPOUNDS AND ANTIBODY-DRUG CONJUGATES THEREOF
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This invention relates to peptidomimetic linkers and anti-body drug conjugates thereof, to pharmaceutical compositions containing them, and to their use in therapy for the prevention or treatment of cancer.
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- Synthesis of Nitriles from Aldoximes and Primary Amides Using XtalFluor-E
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The dehydration reaction of aldoximes and amides for the synthesis of nitriles using [Et2NSF2]BF4 (XtalFluor-E) is described. Overall, the reaction proceeds rapidly (normally 1 h) at room temperature in an environmentally benign solvent (EtOAc) with only a slight excess of the dehydrating agent (1.1 equiv). A broad scope of nitriles can be prepared, including chiral nonracemic ones. In addition, in a number of cases, further purification of the nitrile after the workup was not required.
- Keita, Massaba,Vandamme, Mathilde,Paquin, Jean-Fran?ois
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p. 3758 - 3766
(2015/11/28)
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- P2X3 AND/OR P2X2/3 COMPOUNDS AND METHODS
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The present application provides novel compounds and methods for preparing and using these compounds. In one embodiment, the compounds are of the structure of formula (I), wherein R1-R4 are defined herein. In a further embodiment, these compounds are useful in method for regulating one or both of the P2X3 or P2X2/3 receptors. In another embodiment, these compounds are useful for treating pain in patients by administering one or more of the compounds to a patient.
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Paragraph 0195; 0196; 0197
(2015/07/07)
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- Convenient preparation of primary amides via activation of carboxylic acids with ethyl chloroformate and triethylamine under mild conditions
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Primary amides were easily prepared in 22-99% yields from the corresponding carboxylic acids 1 or 5 with NH4Cl via activation with ClCO 2Et and Et3N. The enantiomers of the corresponding primary amides of Cbz-, Boc-, or Fmoc-α-amino acids can be separated by using a chiral column.
- Noguchi, Takuya,Sekine, Masahiro,Yokoo, Yuki,Jung, Seunghee,Imai, Nobuyuki
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p. 580 - 582
(2013/07/05)
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- Original β,γ-diamino acid as an inducer of a γ-turn mimic in short peptides
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Original αγα tripeptides containing one β,γ-diamino acid have been synthesized and their conformation determined by extensive NMR and molecular dynamic studies. These studies revealed the presence of a C9 hydrogen bonded turn around the β,γ-diamino acid which was stabilized by bulky side chains of the preceding residue. This turn can be considered as a mimic of the well-known γ-turn. The Royal Society of Chemistry 2012.
- Thétiot-Laurent, Sophie,Bouillère, Francelin,Baltaze, Jean-Pierre,Brisset, Fran?ois,Feytens, Debby,Kouklovsky, Cyrille,Miclet, Emeric,Alezra, Valérie
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p. 9660 - 9663
(2013/01/16)
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- Direct synthesis of phosphinopeptides containing C-terminal α-aminoalkylphosphinic acids
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A series of phosphinopeptides containing C-terminal α- aminoalkylphosphinic acids were prepared in good yields directly in one-pot reactions of 2-(N-benzoxycarbonylamino)alkanamides/peptide amides, aldehydes, and aryldichlorophosphines, followed by hydrolysis. In the current method, the peptide bond was formed in a Mannichtype reaction. Springer-Verlag 2010.
- Meng, Fanhua,Xu, Jiaxi
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experimental part
p. 533 - 538
(2010/11/04)
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- AmIno Acid Homologation by the Blaise Reaction: A new entry into nitrogen heterocycles
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(Chemical Equation Presented) A general strategy for the amino acid homologation via Blaise reaction and subsequent reduction is presented. This strategy involves the preparation of protected α-amino nitriles from the corresponding amino acids, followed by the zinc-mediated condensation of tert-butyl bromoacetate, to give the imidazolidones after iminozincate cyclization. Reduction gave the saturated imidazolidinones with cis or trans stereochemistry, depending on the reduction conditions. This strategy was applied to nonfunctionalized amino acids and to functionalized amino acids such as serine and aspartic acid. Additionally, acidic hydrolysis of cis or trans imidazolidinones to the corresponding chiral 4-aminopyrrolidones is described.
- Cam, Thuy Hoang,Bouillere, Francelin,Johannesen, Sine,Zulauf, Anais,Panel, Cecilia,Pouilhes, Annie,Gori, Didier,Alezra, Valerie,Kouklovsky, Cyrille
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experimental part
p. 4177 - 4187
(2009/09/08)
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- N-urethane-protected amino alkyl isothiocyanates: Synthesis, isolation, characterization, and application to the synthesis of thioureidopeptides
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(Chemical Equation Presented) Synthetically useful N-Fmoc amino-alkyl isothiocyanates have been described, starting from protected amino acids. These compounds have been synthesized in excellent yields by thiocarbonylation of the monoprotected 1,2-diamines with CS2/TEA/p-TsCl, isolated as stable solids, and completely characterized. The procedure has been extended to the synthesis of amino alkyl isothiocyanates from Boc- and Z-protected amino acids as well. The utility of these isothiocyanates for peptidomimetics synthesis has been demonstrated by employing them in the preparation of a series of dithioureidopeptide esters. Boc-Gly-OH and Boc-Phe-OH derived isothiocyanates 9a and 9c have been obtained as single crystals and their structures solved through X-ray diffraction. They belong to the orthorhombic crystal system, and have a single molecule in the asymmetric unit (Z′ = 1). 9a crystallizes in the centrosymmetric space group Pbca, while 9c crystallizes in the noncentrosymmetric space group P212121.
- Sureshbabu, Vommina V.,Naik, Shankar A.,Hemantha,Narendra,Das, Ushati,Guru Row, Tayur N.
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supporting information; experimental part
p. 5260 - 5266
(2009/12/06)
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- A Stereoselective entry into functionalized 1,2-diamines by zinc-mediated homologation of α-aminoacids
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A general, stereoselective synthsis of 4,5-disubstituted imidazolidines-2-ones from α-aminoacids has been developed: the key steps are a Biaise reaction of bromoacetate on α-aminonitriles and further reduction. Although reduction with sodium cyanoborohydride afforded a mixture of cis and trans isomers 6a-e with moderate to good stereoselectivity, reduction with sodium in liquid ammonia gave the trans isomers 8a-e with complete stereoselectivity. Acidic hydrolysis of the urea gave 4-amino-pyrrolidinones, which can be precursors to β,γ-diaminoacids or 3-aminopyrrolidines.
- Hoang, Cam Thuy,Alezra, Valerie,Guillot, Regis,Kouklovsky, Cyrille
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p. 2521 - 2524
(2008/02/05)
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- The small peptide-catalyzed direct asymmetric aldol reaction in water
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The asymmetric aldol reaction is a powerful method for forming carbon-carbon bonds. Small peptides with a primary amine as the catalytic residue catalyze asymmetric aqueous aldol reactions between unmodified ketones and aldehydes to furnish the corresponding aldol products with high ees. The high momodularity of the small peptides should enable the construction of several novel catalysts by combinatorial techniques for the aqueous asymmetric aldol reaction. The remarkably high difference in stereoselectivity between the peptide bond-formation was an important step towards the evaluation of asymmetric catalysis and homochilarity.
- Dziedzic, Pawel,Zou, Weibiao,Hafren, Jonas,Cordova, Armando
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- Direct asymmetric intermolecular aldol reactions catalyzed by amino acids and small peptides
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In nature there are at least nineteen different acyclic amino acids that act as the building blocks of poly-peptides and proteins with different functions. Here we report that α-amino acids, β-amino acids, and chiral amines containing primary amine functions catalyze direct asymmetric intermolecular aldol reactions with high enantio-selectivities. Moreover, the amino acids can be combined into highly modular natural and unusual small peptides that also catalyze direct asymmetric intermolecular aldol reactions with high stereoselectivities, to furnish the corre sponding aldol products with up to > 99% ee. Simple amino acids and small peptides can thus catalyze asymmetric aldol reactions with stereoselectivities matching those of natural enzymes that have evolved over billions of years. A small amount of water accelerates the asymmetric aldol reactions catalyzed by amino acids and small peptides, and also increases their stereoselectivities. Notably, small peptides and amino acid tetrazoles were able to catalyze direct asymmetric aldol reactions with high enantioselectivities in water, while the parent amino acids, in stark contrast, furnished nearly racemic products. These results suggest that the prebiotic oligomerization of amino acids to peptides may plausibly have been a link in the evolution of the homochirality of sugars. The mechanism and stereochemistry of the reactions are also discussed.
- Cordova, Armando,Zou, Weibiao,Dziedzic, Pawel,Ibrahem, Ismail,Reyes, Efraim,Xu, Yongmei
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p. 5383 - 5397
(2008/02/13)
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- Structural modification of Fas C-terminal tripeptide and its effects on the inhibitory activity of Fas/FAP-1 binding
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We report the structural requirements of the C-terminal tripeptide derivative of Fas (Ac-Ser-Leu-Val-OH, 1) for the inhibitory activity of Fas/FAP-1 binding. The presence of a carboxyl group and a L-Val residue at the C-terminus is essential for the inhib
- Sawa, Eiji,Takahashi, Motoo,Kamishohara, Masaru,Tazunoki, Tetsushi,Kimura, Kaname,Arai, Midori,Miyazaki, Tetsuko,Kataoka, Shiro,Nishitoba, Tsuyoshi
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p. 3289 - 3299
(2007/10/03)
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- Probing host-selective phytotoxicity: Synthesis and biological activity of phomalide, isophomalide, and dihydrophomalide
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The cyclic depsipeptide phomalide [cyclo(Val-(E)-Aba-Hpp-Hmp-(R)-Leu); Aba = 2-amino-2-butenoic acid, Hpp = (2S)-2-hydroxy-3-phenylpropanoic acid, Hmp = (2S)-2-hydroxy-4-methylpentanoic acid] is the host-selective phytotoxin produced by the fungus [Leptosphaeria maculans (Desm.) Ces. et de Not., asexual stage Phoma lingam (Tode ex Fr.) Desm.] which causes blackleg disease (a devastating disease of several economically important brassica crops). Efficient total syntheses of phomalide, its (Z)-isomer isophomalide, and the two dihydro analogues [(R)-dihydrophomalide and (S)-dihydrophomalide] are described. A [2 + 3] fragment coupling of Cbz-Val-(Z)-Aba with Hpp-Hmp-D-Leu-OBn followed by deprotection and cyclization gave isophomalide which was diastereoselectively isomerized to phomalide by conjugate addition of PhSeH followed by elimination of the corresponding selenoxide. The dihydro analogues were prepared similarly using Cbz-Val-(R)-Abu or Cbz-Val-(S)-Abu (Abu = 2-aminobutanoic acid) in place of Cbz-Val-(Z)-Aba. Biological evaluations of phomalide, isophomalide, and the dihydrophomalides revealed that only phomalide (10-5 M) caused necrotic, chlorotic, and reddish lesions on canola (Brassica napus and Brassica rapa; susceptible to blackleg) leaves whereas no damage was observed on brown mustard (Brassica juncea; resistant to blackleg) or white mustard (Sinapis alba; resistant to blackleg) leaves, even at significantly higher concentrations (10-4 M). Thus, both the presence and configuration of the double bond is crucial for selective phytotoxicity. This is the first reported synthesis of an (E)-Aba-containing natural product, and importantly, the (Z) → (E) isomerization approach should be applicable to other (depsi)peptide targets thereby allowing investigation of the effect of the double-bond configuration on various properties.
- Ward, Dale E.,Vazquez, Alfredo,Soledade,Pedras
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p. 1657 - 1666
(2007/10/03)
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- Synthesis of functionalised oxazoles and bis-oxazoles
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A new method for the synthesis of oxazoles, and in particular chiral non-racemic oxazoles derived from amino acids, has been developed. Thus, rhodium(II) catalysed reaction of diazocarbonyl compounds 6 and 11 in the presence of amides 8 and 10 results in regioselective insertion of the carbenoid into the amide N-H bond with formation of the β-carbonyl amides 9 and 12. Cyclodehydration of amides 9 and 12 using triphenylphosphine-iodine-triethylamine gives functionalised oxazoles 7 and 13. The oxazoles 13c and 13f were converted into the bis-oxazoles 17a and 17b by a second rhodium(II) catalysed regioselective N-H insertion reaction on the amides 15, followed by cyclodehydration.
- Bagley, Mark C.,Buck, Richard T.,Hind, S. Lucy,Moody, Christopher J.
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p. 591 - 600
(2007/10/03)
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- Activation of carboxylic acids by pyrocarbonates. Application of di-tert-butyl pyrocarbonate as condensing reagent in the synthesis of amides of protected amino acids and peptides
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Amides formation from protected amino acids and peptides was achieved in an easy and convenient one-pot procedure using di-tert-butyl pyrocarbonate as activating agent in the presence of pyridine and ammonium hydrogencarbonate. The method gave good yields and did not induce racemization during the amidation of urethane protected amino acids.
- Pozdnev, Vladimir F.
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p. 7115 - 7118
(2007/10/02)
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- Protein backbone modification by novel C(α)-C side-chain scission
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α-Ketoamide (-NH-CO-CO-) units in intact peptides are generated from Ser/Thr residues via Ru(VIII)-catalyzed C(α)-C side-chain scission. Facets associated with this novel α-carbon modification have been probed with 75 peptides chosen to represent every possible peptide environment. The reactions were carried out at room temperature with in situ generated Ru(VIII) in biphasic (CH3CN/CCl4/pH 3 phosphate buffer, 1:1:2 v/v) medium. Whereas Ser/Thr residues placed at the C-terminal end in peptides undergo N-C bond scission leading to des-Ser/Thr peptide amides - thus acting as Gly equivalents in simulating the α-amidating action of pituitary enzymes - those located at the N-terminal or nonterminal or even at the C-terminal position (protected as amide) were found to undergo oxidative C-C bond scission (involving C(α) and C side-chain bond), resulting in the generation of α-ketoamide (-NH-CO-CO-) units in the intact peptide backbone. The difference in the products arising from C(α)-C side-chain scission of Ser/Thr esters and amides is rationalized on the basis of a common mechanism involving either oxaloesters [PeP-NH-CO-COX; X = OMe] or oxalamides [X = NH2 or NH-Pep] arising from the oxidation of initially formed carbinolamide intermediates [Pep-NH-CH(OH)-COX], wherein, while the former are shown to undergo hydrolysis to terminal amides [Pep-NH2], the oxalamides are found to be stable to hydrolysis. Ancillary noteworthy findings are those of peptide bond scission when contiguous Ser-Ser/Thr-Thr residues are present and the oxidative cleavage at C-terminal Tyr/Trp sites generating des amides. The oxidative methodology presented here is mild, simple, and practical and proceeds with chiral retention. The insensitivity of a large number of amino acid residues, such as Gly, Ala, Leu, Asn, Gln, Asp, Glu, Pro, Arg, Phe, Lys, Val, and Aib, and N-protecting groups, such as Boc, Z, and Bz, toward Ru(VIII) under the experimental conditions should make this methodology practical and useful. Sulfur-containing amino acids Cys and Met get oxidized to sulfones in the products.
- Ranganathan,Vaish,Shah
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p. 6545 - 6557
(2007/10/02)
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- Dichlorotris(dimethylamino)phosphorane as a Dehydratisation Reagent for the Preparation of N-Protected Amino Acid Amides
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Besides for the synthesis of peptides and activated esters dichlorotris(dimethylamino)phosphorane (2) now proved to be an excellent reagent for the preparation of N-protected amino acid amides.
- Appel, Rolf,Hiester, Ernst
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p. 2037 - 2040
(2007/10/02)
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- Ammonolysis of N-Acylpyroglutamic Acid. Permanganate oxidation of Peptides. II.
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The reaction of N-acylpyroglutamic acid with ammonia proceeds in two pathways.The one results in N-acylglutamine as a product, and the other in pyroglutamic acid and an amide formed from the N-acyl group.The ratio of the yields of the two reactions changes with the N-acyl group, being correlated with the acidity of the carboxylic acid from which the N-acyl group is derived, and also with the steric hindrance of the group.
- Torigoe, Keisuke,Motoki, Yoshiaki,Muramatsu, Ichiro
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p. 1263 - 1264
(2007/10/02)
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