- Design and Optimization of a Continuous Stirred Tank Reactor Cascade for Membrane-Based Diazomethane Production: Synthesis of α-Chloroketones
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The development of a continuous diazomethane generator comprising a continuous stirred tank reactor (CSTR) cascade and membrane separation technology is reported. This reactor concept was applied for the telescoped three-step synthesis of a chiral α-chloroketone, a key building block for many HIV protease inhibitors, via a modified Arndt-Eistert reaction starting from N-protected l-phenylalanine. The initial mixed anhydride was generated in a coil reactor and directly introduced into the CSTR diazomethane cascade. The use of a semipermeable Teflon membrane (AF-2400) allowed the generation of anhydrous diazomethane, which diffuses through the membrane into the CSTR where it is immediately consumed by the anhydride to furnish the corresponding diazoketone. The subsequent halogenation with concentrated HCl was performed downstream in batch and allowed production of the α-chloroketone on a multigram scale, with a productivity of 1.54 g/h (5.2 mmol/h).
- Wernik, Michaela,Poechlauer, Peter,Schmoelzer, Christoph,Dallinger, Doris,Kappe, C. Oliver
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- A practical method for the preparation of α'-chloroketones of N-carbanaate protected-α-aminoacids
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A practical method for the preparation of α-N-BOC-epoxides from protected amino acid esters based on the Kowalski homologation reaction is described. This procedure can be readily performed on a large scale without the use of hazardous reagents and has allowed preparation of epoxides 3 in multi-kilogram quantities.
- Chen, Ping,Cheng, Peter T. W.,Spergel, Steven H.,Zahler, Robert,Wang, Xuebao,Thottathil, John,Barrish, Joel C.,Polniaszek, Richard P.
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- Practical synthesis of α-aminoalkyl-α′-chloromethylketone derivatives. Part 2: Chloromethylation of N-imine-protected amino acid esters
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Chloromethylation of N-imine-protected amino acid esters followed by acid hydrolysis gave α-aminoalkyl-α′-chloromethylketone as a HCl salt form in good yield without racemization. The amino group was conveniently protected with carbamate protecting reagents to give various useful intermediates for the protease inhibitors.
- Onishi, Tomoyuki,Nakano, Takashi,Hirose, Naoko,Nakazawa, Masakazu,Izawa, Kunisuke
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- Synthesis method of (2S, 3S)-3-(t-butyloxycarboryl amino)-1, 2-epoxy-4-phenylbutane
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The invention relates to the technical field of synthesis of drug intermediates, in particular to a synthesis method of (2S, 3S)-3-(t-butyloxycarboryl amino)-1, 2-epoxy-4-phenylbutane. The method comprises the following steps: condensing N-t-butyloxycarboryl-L-phenylalanine serving as a raw material with substituted phenol under the action of a condensing agent to obtain active ester 15; reacting the active ester 15 with a ylide reagent and alkali to obtain a sulfoxide ylide intermediate 16; reacting the sulfoxide ylide intermediate 16 with halide salt under the action of a catalyst to obtain a halogenated ketone intermediate 6; reducing the halogenated ketone intermediate 6 through a reducing agent under the action of a catalyst to obtain a halogenated methanol intermediate 7; and removing halogen acid from the halogenated methanol intermediate 7 under the action of alkali, and carrying out condensation cyclization to obtain the target product (2S, 3S)-3-(t-butyloxycarboryl amino)-1, 2-epoxy-4-phenylbutane. The synthesis method of the (2S, 3S)-3-(t-butyloxycarboryl amino)-1, 2-epoxy-4-phenylbutane, provided by the invention, has the characteristics of cheap and easily available initial raw materials, safe and controllable process and easiness in operation.
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- SULFOXONIUM YLIDE DERIVATIVES AS PROBES FOR CYSTEINE PROTEASE
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The present invention relates to compounds of formula I bearing a sulfoxonium ylide moiety as warhead, or salts thereof. Such compounds can be used as activity-based probes for cysteine proteases such as cathepsin X, in methods of detecting cysteine protease activity and in related diagnostic or therapeutic methods.
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Paragraph 0451; 0455-0460
(2020/07/14)
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- A process for the preparation method of the sulfuric acid [...] intermediates
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The invention discloses a method for preparing sulfuric acid [...] intermediate (2 R, 3 S) - 1, 2 - epoxy - 3 - tert-butoxycarbonyl amino - 4 - phenyl butane of the method, the method cheap L - phenylalanine as the starting material, by with the di-T-n-butyl reaction for protecting amino group, with acetic anhydride condensation, with hydrochloric acid after the occurrence of the chloro in the chiral catalyst under the effects of the asymmetric hydrogenation reduction, finally cyclization under basic conditions to obtain the target product. The present invention provides of sulfuric acid is an important intermediate [...] (2 R, 3 S) - 1, 2 - epoxy - 3 - tert-butoxycarbonyl amino - 4 - phenyl butane preparation method of the raw material is cheap, mild reaction conditions, the synthesis efficiency is high, it is suitable for industrial production, in order to prepare sulfuric acid [...] and intermediate provides a highly efficient way.
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Paragraph 0027; 0028
(2019/07/08)
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- 4-amino-N-[ (2R, 3S) - 3-amino-2-hydroxy-4-phenyl-butyl]-N- isobutyl-benzene sulfonaide preparation method
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The invention discloses a method for preparing 4-amino-N-[(2R,3S)-3-amino-2-hydroxy-4-benzene butyl]-N-isobutyl benzsulfamide. The method comprises the following steps: S1: enabling L-phenylalanine and diazomethane to react to obtain a diazo methyl ketone intermediate product, and enabling the diazo methyl ketone intermediate product and haloid acid to react to obtain a compound A; S2, conducting carbonyl deoxidation on the compound A to obtain a compound B; S3, under the existence of iso-butylamine, conducting cyclization reaction and ring-opening reaction on the compound B in sequence to obtain a compound C; S4, enabling the compound C and nitrobenzenesulfonyl chloride to react to obtain a compound D; S5, conducting nitro reduction on the compound D to obtain the 4-amino-N-[(2R,3S)-3-amino-2-hydroxy-4-benzene butyl]-N-isobutyl benzsulfamide. The method is simple in course, low in cost, mild in condition, and higher in intermediate product stability, and is beneficial for industrial application.
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Paragraph 0079-0071
(2017/03/17)
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- METHOD FOR THE PREPARATION OF DIAZOALKANES
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The present invention relates to a method of forming diazoalkanes. One aspect of the present invention provides a method for the production of a N-alkyl-N-nitroso compound from a starting material, comprising the use of a tribasic acid to acidify an amine. A second aspect of the present invention provides a method for the production of a diazoalkane, comprising reacting a N-alkyl-N-nitroso compound with a base and a phase transfer catalyst, wherein no organic solvent is used.
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- Continuous flow synthesis of α-halo ketones: Essential building blocks of antiretroviral agents
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The development of a continuous flow process for the multistep synthesis of α-halo ketones starting from N-protected amino acids is described. The obtained α-halo ketones are chiral building blocks for the synthesis of HIV protease inhibitors, such as atazanavir and darunavir. The synthesis starts with the formation of a mixed anhydride in a first tubular reactor. The anhydride is subsequently combined with anhydrous diazomethane in a tube-in-tube reactor. The tube-in-tube reactor consists of an inner tube, made from a gas-permeable, hydrophobic material, enclosed in a thick-walled, impermeable outer tube. Diazomethane is generated in the inner tube in an aqueous medium, and anhydrous diazomethane subsequently diffuses through the permeable membrane into the outer chamber. The α-diazo ketone is produced from the mixed anhydride and diazomethane in the outer chamber, and the resulting diazo ketone is finally converted to the halo ketone with anhydrous ethereal hydrogen halide. This method eliminates the need to store, transport, or handle diazomethane and produces α-halo ketone building blocks in a multistep system without racemization in excellent yields. A fully continuous process allowed the synthesis of 1.84 g of α-chloro ketone from the respective N-protected amino acid within ~4.5 h (87% yield).
- Pinho, Vagner D.,Gutmann, Bernhard,Miranda, Leandro S. M.,De Souza, Rodrigo O. M. A.,Kappe, C. Oliver
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p. 1555 - 1562
(2014/03/21)
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- CRYSTALLINE DARUNAVIR
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The present invention relates to a non-solvated crystalline Darunavir, process for its preparation and pharmaceutical composition comprising it. The present invention also relates to a process for the preparation of amorphous Darunavir from a non-solvated crystalline Darunavir.
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Page/Page column 5
(2013/08/15)
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- A METHOD FOR THE PREPARATION OF DIAZOALKANES
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The present invention relates to a method of forming diazoalkanes. One aspect of the present invention provides a method for the production of a N-alkyl-N-nitroso compound from a starting material, comprising the use of a tribasic acid to acidify an amine. A second aspect of the present invention provides a method for the production of a diazoalkane, comprising reacting a N-alkyl-N-nitroso compound with a base and a phase transfer catalyst, wherein no organic solvent is used,
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- PROCESSES FOR THE PREPARATION OF ALPHA-CHLOROKETONES FROM CARBOXYLIC ACIDS
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The present disclosure provides compositions and methods for the preparation of ? chloroketones from carboxylic acids. In particular embodiments, the present disclosure provides procedures for the preparation of chiral ? chloroketone derivatives of amino acids.
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Page/Page column 6; 38; 39
(2010/11/03)
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- One-Carbon Chain Extension of Esters to α-Chloroketones: A Safer Route without Diazomethane
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The reaction of a variety of methyl esters with dimethylsulfoxonium methylide at 0-25 °C affords the chain-extended β-keto dimethylsulfoxonium ylides. Subsequent treatment with hydrogen chloride in THF proceeds with loss of DMSO to afford the corresponding α-chloroketones. This sequence has been utilized to convert the methyl esters of CBZ-protected alanine and valine to the anti N-protected α-amino epoxides, which are important pharmaceutical intermediates. When the same protocol is applied to BOC-protected phenylalanine methyl ester, epimerization occurs so that the use of a more reactive aryl ester is required. This chemistry provides a practical route to α-chloroketones that avoids the use of toxic and explosive diazomethane.
- Wang, Dengjin,Schwinden, Mark D.,Radesca, Lilian,Patel, Bharat,Kronenthal, David,Huang, Ming-Hsing,Nugent, William A.
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p. 1629 - 1633
(2007/10/03)
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- Stereoselective synthesis of photoreactive peptidomimetic γ-secretase inhibitors
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The first asymmetric synthesis of novel, potent photoreactive γ-secretase inhibitors 2 and 3 has been accomplished. Two Stereoselective methods for the preparation of lactone 9 are described. Protected benzophenone intermediate 19 is prepared via an aldol-elimination reaction followed by a PtO2-catalyzed asymmetric hydrogenation. Two routes leading from 19 to compounds 2 and 3 are evaluated. The application of 3 as an activity-based probe has been demonstrated by localizing γ-secretase activity in the plasma membrane of intact cells.
- Chun, Jiong,Yin, Ye Ingrid,Yang, Guangli,Tarassishin, Leonid,Li, Yue-Ming
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p. 7344 - 7347
(2007/10/03)
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- PROCESS FOR PRODUCING ALPHA-AMINOHALOMETHYL KETONE DERIVATIVES
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Herein is disclosed a process for producing an α-aminohalomethyl ketone derivative which comprises subjecting to catalytic reduction the corresponding α-aminodihalomethyl ketone derivative, and which process is efficient and suited for industrial production thereof.
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Page/Page column 7-8
(2010/11/29)
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- Process for producing alpha-aminohalomethyl ketone derivatives
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Herein is disclosed a process for producing an α-aminohalomethyl ketone derivative which comprises subjecting to catalytic reduction the corresponding α-aminodihalomethyl ketone derivative, and which process is efficient and suited for industrial production thereof.
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- Process for producing alpha-aminoketones
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An amino group of an α-amino acid ester is protected as an imine, and it is then reacted with a halomethyllithium to obtain an N-protected-α-aminohalomethylketone. Further, this N-protected-α-aminohalomethylketone is treated with an acid to obtain an α-aminohalomethylketone. This process is suited for industrial production, and can produce an α-aminohalomethylketone and its related compounds economically and efficiently.
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- Process for producing alpha-aminoketones
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A process for producing α-aminohalomethyl ketones or N-protected α-aminohalomethyl ketones from specified 3-oxazolidin-5-one derivatives via 5-halomethyl-5-hydroxy-3-oxazolidine derivatives. By this process, α-aminohalomethyl ketones and compounds relating to them can be obtained efficiently and economically in industrial scale.
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- Process for the preparation of alpha' chloroketones
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The present invention relates to a process for the preparation of α′ chloroketones, such as 4-phenyl-3-t-butyloxy-carbonylamino)-2-keto-1-chlorobutane by reacting certain aryl amino acid esters, e.g. N-(2-t-butoxycarbonyl)-L-phenylalanine-4-nitrophenyl ester, with a sulfur ylide compound to form the corresponding keto ylide compound which is then treated with a source of chloride and an organic acid.
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- Dihalomethylation of N-protected phenylalanine esters
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Dihalomethylation of several N-protected amino acid esters gave N-protected α-aminoalkyl-α′-dihalomethylketones, which are useful intermediates for the synthesis of erythro β-amino-α-hydroxycarboxylic acids, in good yield. The dihalomethylketones were successfully converted to N-protected α-aminoalkyl-α′-halomethylketones by selective catalytic hydrogenation.
- Onishi, Tomoyuki,Otake, Yasuyuki,Hirose, Naoko,Nakano, Takashi,Torii, Takayoshi,Nakazawa, Masakazu,Izawa, Kunisuke
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p. 6337 - 6340
(2007/10/03)
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- Preparation of α-chloroketones by the chloroacetate Claisen reaction
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Claisen condensation of the dianion of chloroacetic acid with N-BOC alpha-amino acid methyl esters provides the corresponding α-chloroketones in high yield and enantiomeric excess.
- Wang, Xuebao,Thottathil, John K.,Polniaszek, Richard P.
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p. 902 - 904
(2007/10/03)
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- Process for producing 3-amino-2-oxo-1-halogenopropane derivatives
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Compounds formed by reacting a protected amino acid with an alkali metal enolate of an alkyl acetate are reacted with a halogenating agent for halogenation of the 2-position, or a protected amino acid is reacted with an alkali metal enolate of an alkyl halogenoacetate, to form a 4-amino-3-oxo-2-halogenobutanoic acid ester derivative, and hydrolysis and decarboxylation are conducted to produce a 3-amino-2-oxo-1-halogenopropane derivative or its salt. The present method is a useful process for producing a 3-amino-2-oxo-1-halogenopropane derivatives which can easily be converted to a 3-amino-1,2-epoxypropane.
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- Synthesis and activity of HIV protease inhibitors
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We report here the synthesis and activity of HIV protease inhibitors. In the first stage hydrophobic compounds incorporating a 'carba' bond surrogate or a beta-homologated residue were synthesized. Secondly, we synthesized cyclic compounds in which we incorporated 2-quinoline carboxylic acid in the P3 position and the amino-hydroxyindane moiety in the P'3. The last part of this work was dedicated to a structure/activity study of a peptide substrate. These modifications allowed us to work up the synthesis of new pseudopeptide bonds: amino-amide and hydroxy-amide. Compounds with activity in the micromolar range were actually a starting point for the synthesis of new protease inhibitors.
- Garrouste, Patrick,Pawlowski, Macek,Tonnaire, Thierry,Sicsic, Sames,Dumy, Pascal,De Rosny, Eve,Reboud-Ravaux, Michele,Fulcrand, Pierre,Martinez, Jean
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p. 423 - 436
(2007/10/03)
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- Aminodiol HIV Protease Inhibitors. 1. Design, Synthesis, and Preliminary SAR
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A series of HIV protease inhibitors containing a novel C2 symmetrical "aminodiol" core structure were prepared from amino acid starting materials.The ability of the aminodiols to inhibit HIV replication in cell culture is comparable to their ability to inhibit the isolated enzyme, a result compatible with good cell membrane penetration by this class of compounds.Optimization of the structure-activity in this series led to aminodiol 9a (Ki = 100 nM; ED50(HIV-1) = 80 nM) containing P1/P1' benzyl and P2/P2' Boc substituents.Compound 9a is a selective inhibito r of HIV protease versus other aspartyl proteases such as human renin, human cathepsin D, and porcine pepsin.In addition, 9a is equipotent against HIV-1 and HIV-2 in cell culture and demonstrates similar activity in infected T-lymphocytes and PBMCs.After iv and oral administration in rats, 9a displayed significant oral bioavailability (ca. 40percent) and a promising plasma elimination half-life (4 h).
- Barrish, Joel C.,Gordon, Eric,Alam, Masud,Lin, Pin-Fang,Bisacchi, Gregory S.,et al.
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p. 1758 - 1768
(2007/10/02)
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- Development of active center-directed plasmin and plasma kallikrein inhibitors and studies on the structure-inhibitory activity relationship
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The molecule of trans-4-aminomethylcyclohexanecarbonylphenylalanine 4- carboxymethylanilide (8), which is a potent and selective inhibitor of plasma kallikrein, can be divided into three parts (P1, P1 and P2), each of which contains one of the rings. In order to study the role of each part in the manifestation of potent and selective inhibitory activity and the relationship between the structure and inhibitory activities toward plasmin, plasma kallikrein, urokinase and thrombin, each part was substituted with various other moieties to give many kinds of analogs and their inhibitory activities against the above enzymes were examined. Among them, trans-4- aminomethylcyclohexanecarbonyl-O-2-bromobenzyloxycarbonyltyrosine 4- acetylanilide (12) inhibited plasmin and plasma kallikrein with IC50 values of 2.3 x 10-7 M and 3.7 x 10-7 M, and K(i) values of 1.2 x 10-7 M and 1.3 x 10-7 M, respectively.
- Teno,Wanaka,Okada,Taguchi,Okamoto,Hijikata-Okunomiya,Okamoto
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p. 1079 - 1090
(2007/10/02)
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