- Al(OtBu)3 as an effective catalyst for the enhancement of Meerwein-Ponndorf-Verley (MPV) reductions
-
The Meerwein-Ponndorf-Verley (MPV) reduction of aldehydes and ketones has been the cornerstone in many multistep syntheses. Herein we report the use of Al(OtBu)3 instead of the commonly used Al(OiPr)3 which results in a dramatic rate increase and significantly lower catalyst loading for the reduction of (1) model compounds benzaldehyde and acetophenone, and (2) N-(tert-butyloxycarbonyl)-(3S)-3-amino-1-chloro-4-phenyl-2-butanone or (S)-CMK, a key intermediate in HIV protease inhibitor synthesis.
- Flack, Kyle,Kitagawa, Kristen,Pollet, Pamela,Eckert, Charles A.,Richman, Kent,Stringer, Joy,Dubay, William,Liotta, Charles L.
-
-
Read Online
- Diastereoselective microbial reduction of (S)-[3-chloro-2-oxo-1- (phenylmethyl)propyl]carbamic acid, 1,1-dimethylethyl ester
-
The chiral intermediate (1S,2R)-[3-chloro-2-hydroxy-1-(phenylmethyl)propyl] carbamic acid, 1,1-dimethylethyl ester 2a was prepared for the total synthesis of the HIV protease inhibitor Atazanavir. The diastereoselective reduction of (1S)-[3-chloro-2-oxo-1-(phenylmethyl)propyl] carbamic acid, 1,1-dimethyl-ethyl ester 1 was carried out using microbial cultures among, which Rhodococcus, Brevibacterium, and Hansenula strains reduced 1 to 2a. Three strains of Rhodococcus gave >90% yield. A diastereomeric purity of >98% and enantiomeric excess of >99.3% were obtained for alcohol 2a.
- Patel, Ramesh N.,Chu, Linda,Mueller, Richard
-
-
Read Online
- Preparation method of anti-HIV protease inhibitor intermediate
-
The invention relates to the technical field of medicine preparation, in particular to a preparation method of an anti-HIV protease inhibitor intermediate. According to the invention, the anti-HIV protease inhibitor intermediate disclosed as a formula II or a formula III shown in the description is obtained by reacting a compound shown in a formula I defined in the description as a raw material, a catalyst A or catalyst B serving as a catalyst and dichloromethane and an aprotic polar solvent serving as a mixed solvent in the presence of formate. Firstly, the preparation method of the novel anti-HIV protease inhibitor intermediate, which is mild in condition, safe in process and suitable for industrial production, is created, and the reaction conditions are further explored and optimized, so that the reaction yield and purity are greatly improved.
- -
-
Paragraph 0010; 0043-0046; 0049-0052
(2021/07/31)
-
- Synthetic method of HIV protease inhibitor intermediate compound
-
The invention is suitable for the technical field of drug synthesis, and provides a synthesis method of an HIV protease inhibitor intermediate compound. The method comprises the following steps: underthe protection of argon, adding a catalyst and hydrogen source mixture into a compound 1a in a reaction solvent, and carrying out asymmetric transfer hydrogenation reaction to obtain the HIV proteaseinhibitor intermediate compound 2a or 2a'. The synthetic route is shown as follows: the group R is one of tert-butyloxycarboryl, carbobenzoxy, p-toluenesulfonyl, acetyl and benzoyl. The asymmetric transfer hydrogenation technology is utilized, compared with existing similar intermediates, the stereoselectivity and yield of the synthesized HIV protease inhibitor intermediate compound can be greatly improved, and the diastereoselectivity ratio of the product reaches 94:6; and in addition, the catalyst is low in dosage and high in catalytic efficiency, reaction activity is improved, raw materialloss is low, the whole process is rapid, simple and convenient, and cost is greatly reduced.
- -
-
Paragraph 0032-0050; 0053-0056
(2021/03/06)
-
- Rh(iii)-Catalyzed diastereoselective transfer hydrogenation: An efficient entry to key intermediates of HIV protease inhibitors
-
A highly efficient diastereoselective transfer hydrogenation of α-aminoalkyl α′-chloromethyl ketones catalyzed by a tethered rhodium complex was developed and successfully utilized in the synthesis of the key intermediates of HIV protease inhibitors. With the current Rh(iii) catalyst system, a series of chiral 3-amino-1-chloro-2-hydroxy-4-phenylbutanes were produced in excellent yields and diastereoselectivities (up to 99% yield, up to 99?:?1 dr). Both diastereomers of the desired products could be efficiently accessed by using the two enantiomers of the Rh(iii) catalyst.
- Chen, Gen-Qiang,Lang, Qi-Wei,Phansavath, Phannarath,Ratovelomanana-Vidal, Virginie,Wang, Fangyuan,Wu, Ting,Yin, Congcong,Zhang, Xumu,Zheng, Long-Sheng
-
supporting information
p. 3119 - 3122
(2020/03/23)
-
- A (2 R, 3 S) - 1 - chloro - 3 - tert-butoxy amide - 4 - phenyl - 2 - butanol preparation method
-
The invention provides a preparation method for (2R,3S)-1-chlorine-3-tert-butoxycarbonylamino-4-phenyl-2-butanol. The preparation method comprises the steps that L-phenylalanine is taken as raw materials, protected by adopting benzyl, esterified and then catalyzed through NMM to generate a mixed anhydride compound, the mixed anhydride compound reacts with diazomethane to generate diazoketone, a reduction reaction and palladium carbon reduction are performed, and finally the intermediate (2R,3S)-1-chlorine-3-tert-butoxycarbonylamino-4-phenyl-2-butanol is obtained. According to the preparation method, the low-cost benzyl is adopted to protect amidogen, the synthetic route is reasonable, the operation technology is simple, safe and high in yield, industrialization can be well achieved, and the production efficiency is improved.
- -
-
-
- Chiral chlorohydrins from the biocatalyzed reduction of chloroketones: Chiral building blocks for antiretroviral drugs
-
E. coli cells that contain overexpressed alcohol dehydrogenases (ADHs) were screened as biocatalysts for the stereoselective reduction of chloroketones 5 a-d, the corresponding halohydrins 6 a-d of which are building blocks in the synthesis of antiretroviral drugs. Among them, ADH from Sphingobium yanoikuyae was found to reduce chloroketone 5 c with a high stereoselectivity (90 % de) and conversion (85 %) to furnish threo halohydrin (R,S)-6 c. ADH from Ralstonia sp. (RasADH) was able to reduce 5 a and 5 b with complementary diastereoselectivity to provide access to both threo and erythro halohydrins through "substrate-based" stereocontrol. The RasADH-catalyzed reductions were optimized to provide (R,S)-6 a with 98 % conversion and 84 % diastereomeric excess (de) and (S,S)-6 b with 95 % conversion and 86 % de. Molecular modeling studies showed that 5 b, which features a carboxybenzyl protecting group, is able to bind to the enzyme catalytic site in an "inverted" mode in comparison to tert-butyloxycarbonyl- and methyloxycarbonyl-protected substrates 5 a and 5 c, which sheds light on the observed switching of the stereopreference. RasADH-catalyzed reductions were optimized to provide (R,S)-6 a with 98 % conversion and 84 % de and (S,S)-6 b with 95 % conversion and 86 % de.
- De Miranda, Amanda S.,Simon, Robert C.,Grischek, Barbara,De Paula, Gabriel C.,Horta, Bruno A. C.,De Miranda, Leandro S. M.,Kroutil, Wolfgang,Kappe, C. Oliver,De Souza, Rodrigo O. M. A.
-
p. 984 - 992
(2015/03/18)
-
- REDUCTION OF ALDEHYDES AND KETONES TO ALCOHOLS
-
The embodiments described herein provide a reduction of an aldehyde or a ketone, such as a Meerwein-Ponnorf-Verley (MPV) reaction of an aldehyde or ketone. In some embodiments, the reaction occurs in the presence of A1[OC(CH3)3]. In some embodiments, the reaction occurs in the presence of an aprotic solvent. In some embodiments, the aldehyde or ketone is an amino aldehyde or an amino ketone wherein the amine is group is protected such that the nitrogen of the amine has no proton. Other embodiments related to compositions and compounds related to the reduction reaction, or to the preparation or use of the aldehyde, the ketone, or the resulting alcohol.
- -
-
Page/Page column 20
(2011/06/16)
-
- Carbonyl reductase, gene thereof and method of using the same
-
The present invention relates to a polypeptide having an activity to asymmetrically reduce (3S)-1-chloro-3-tert-butoxycarbonylamino-4-phenyl-2-butanone to produce (2R,3S)-1-chloro-3-tert-butoxycarbonylamino-4-phenyl-2-butanol isolated from a microorganism belonging to the genus Ogataea, a DNA encoding the polypeptide and a transformant that produces the polypeptide. The present invention moreover relates to a method of producing (2R,3S)-1-chloro-3-tert-butoxycarbonylamino-4-phenyl-2-butanol utilizing the polypeptide or the transformant. Using the polypeptide or transformant of the present invention, optically active alcohols such as (2R,3S)-1-chloro-3-tert-butoxycarbonylamino-4-phenyl-2-butanol and the like can be produced efficiently.
- -
-
-
- Production method of aminochlorohydrin sulfate
-
Highly pure (2R,3S)-3-tert-butoxycarbonylamino-1-chloro-2-hydroxy-4-phenylbutane or (2S,3R)-3-tert-butoxycarbonylamino-1-chloro-2-hydroxy-4-phenylbutane may be conveniently produced in high yield by: (a) reacting compound (1) with lithiumchloromethane to give compound (2) and at least a byproduct; (b) dissolving compound (2) and the byproduct in a polar solvent and adding water to the solution to precipitate compound (2) as crystals; (c) reducing the crystals of compound (2) to give compound (3) and at least its diastereomer as an impurity; (d) adding sulfuric acid thereto to give compound (4) and at least its diastereomer as an impurity; and (e) precipitating compound (4) as crystals from a solution containing acetic acid ester or acetic acid ester.
- -
-
Page/Page column 21
(2010/11/26)
-
- PROCESS FOR ASYMMETRIC CATALYTIC HYDROGENATION
-
The invention provides a process for preparing optically active 1,2-haloalcohols from an α-haloketone by asymmetric catalytic hydrogenation of a-haloketones comprising providing a substrate comprising an a-haloketone and contacting the substrate with a hydrogenation reagent under conditions effective for hydrogenation of the substrate in the presence of a catalyst comprising ruthenium or rhodium coordinated to a bisphosphine ligand.
- -
-
Page/Page column 7; 15-16
(2008/06/13)
-
- Stereoselective synthesis of photoreactive peptidomimetic γ-secretase inhibitors
-
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
-
p. 7344 - 7347
(2007/10/03)
-
- Asymmetric transfer hydrogenation of α-aminoalkyl α′-chloromethyl ketones with chiral Rh complexes
-
Asymmetric transfer hydrogenation of N-substituted (3S)-3-amino-1-chloro-4- phenyl-2-butanones in the presence of Cp*RhCl[(R,R)-Tsdpen] (S/C = 1000) with a mixture of formic acid/triethylamine gave N-substituted (2R,3S)-3-amino-1-chloro-2-hydroxy-4-phenylbutanes with up to 93% de in a quantitative yield, and reduction with the enantiomeric catalyst Cp*RhCl[(S,S)-Tsdpen] gave (2S.3S)-diastereomeric alcohol with up to 96% de.
- Hamada, Takayuki,Torii, Takayoshi,Onishi, Tomoyuki,Izawa, Kunisuke,Ikariya, Takao
-
p. 7391 - 7394
(2007/10/03)
-
- PROCESSES FOR PREPARATION OF N-PROTECTED- -AMINO ALCOHOLS AND N-PROTECTED- -AMINO EPOXIDES
-
Herein are disclosed a process for increasing in purity, or purifying, an N-protected-β-aminoalcohol which process comprises (i) adding water to a polar organic solvent in which an N-protected-β-aminoalcohol such as a (2R,3S)-or (2S,3R)-3-tert-butoxycarbonylamino-1-halo-2-hydroxy-4-phenylbutane or the like, or (ii) crystallizing such an N-protected-β-aminoalcohol from a diol or a diol-based mixed solvent, and a process for producing the corresponding N-protected-β-aminoepoxide which process comprises treating, with a base, the thus purity-enhanced N-protected-β-aminoalcohol. Such N-protected-β-aminoalcohols and N-protected-β-aminoepoxides are both useful as synthetic intermediates for medicine compounds, such as, e.g., HIV protease inhibitor and the like.
- -
-
-
- Production method of beta-amino-alpha-hydroxycarboxylic acid
-
The present invention provides a production method of an optically active β-amino-α-hydroxycarboxylic acid, which includes the following steps (a)-(c): (a) treating an optically active N-carbamate protected β-amino epoxide with an acid to give an optically active 5-hydroxymethyl-2-oxazolidinone; (b) oxidizing the resulting compound in the presence of 2,2,6,6-tetramethyl-1-piperidinyloxy and hypochlorite to give an optically active 4-benzyl-2-oxo-5-oxazolidinecarboxylic acid; and (c) treating the 4-benzyl-2-oxo-5-oxazolidinecarboxylic acid with a base, and a production method of an optically active N-carbamate protected β-amino-α-hydroxycarboxylic acid which includes protection of the amino group with a carbamate type protecting group. The industrial production method of the present invention can produce these compounds efficiently.
- -
-
-
- Method for producing epoxide crystal
-
The invention relates to a method for industrially producing highly pure (2R, 3S)- or (2S, 3R)-N-carbamate-protected β-aminoepoxide (crystal) or (2R, 3S)- or (2S, 3R)-N-carbamate-protected β-aminoalcohol. The method for producing N-carbamate-protected β-aminoepoxide crystal, includes one or more of the following steps (a) to (d): (a) dissolving (2R, 3S)- or (2S, 3R)-N-carbamate-protected β-aminoalcohol containing at least the diastereomer as an impurity in a solvent including at least one or more selected from aromatic hydrocarbon solvent, saturated hydrocarbon solvent, aqueous mixture solvent, acetone and 2-propanol, to remove insoluble matters; (b) treating the (2R, 3S)- or (2S, 3R)-N-carbamate-protected β-aminoalcohol with a base, thereby converting the N-carbamate-protected β-aminoalcohol to (2R, 3S)- or (2S, 3R)-N-carbamate-protected β-aminoepoxide; (c) treating the (2R, 3S)- or (2S, 3R)-N-carbamate-protected β-aminoepoxide containing at least the diastereomer as an impurity with an acid, thereby converting the diastereomer as an impurity to (4S, 5R) or (4R, 5S) oxazolidin-2-one derivative, and optionally separating and removing the resulting oxazolidin-2-one derivative in water or an aqueous mixture solvent; and (d) crystallizing the (2R, 3S)- or (2S, 3R)-N-carbamate-protected β-aminoepoxide in a mixture solvent of water and water-miscible organic solvent. By the methods of the present invention, highly pure (2R, 3S)- or (2S, 3R)-N-carbamate-protected β-aminoepoxide or (2R, 3S) or (2S, 3R)-N-carbamate-protected β-aminoalcohol can be efficiently produced.
- -
-
-
- METHOD FOR PURIFYING AND ISOLATING (2S,3S)- OR (2R,3S)-HALOHYDRIN DERIVATIVES
-
The present invention has for its object to provide a practical method for the purification and isolation on a commercial scale of said compound (1) or compound (2) in good yield and with high quality. The present invention provides a purification/isolation method of a (2S,3S)-1-halo-2-hydroxy-3-N-(tert-butoxycarbonyl)amino-4-phenylbutane (1) or a (2R,3S)-1-halo-2-hydroxy-3-N-(tert-butoxycarbonyl)amino-4-phenylbutane (2) which comprises, for the purpose of removing contaminant impurity from a mixture containing at least one of said compounds(1) and (2), causing the objective compound (1) or compound (2) to be crystallized in the presence of a solvent comprised of a hydrocarbon solvent and then collecting the obtained crystals.
- -
-
-
- Process for reducing α-amino ketones
-
The present invention has its objects to provide a method for reducing α-aminoketone derivatives under mild conditions with high stereoselectivity. This invention is a method for reducing α-aminoketone which comprises reacting an a-aminoketone derivative of general formula (1) with a compound prepared from an organoaluminum compound of general formula (4), a sulfonic acid derivative of general formula (5), and an alcohol compound of general formula (6) to give an α-aminoalcohol derivative of general formula (7)
- -
-
-
- Biocatalytic synthesis of chiral intermediates for antiviral and antihypertensive drugs
-
The chiral intermediate (1S,2R) [3-chloro-2-hydroxy-1-(phenylmethyl)propyl] carbamic acid, 1,1-dimethyl-ethyl ester 2a was prepared for the total synthesis of a human immunodeficiency virus protease inhibitor, BMS-186318. The stereoselective reduction of (1S) [3-chloro-2-oxo-1(phenylmethyl)propyl] carbamic acid, 1,1-dimethylethyl ester 1 was carried out using microbial cultures, among which Streptomyces nodosus SC 13149 efficiently reduced 1 to 2a. A reaction yield of 80%, enantiomeric excess (e.e.) of 99.8%, and diastereomeric purity of 99% were obtained for chiral alcohol 2a. Chiral L-6-hydroxy norleucine 3, an intermediate in the synthesis of antihypertensive drug, was prepared by reductive amination of 2-keto-6-hydroxyhexanoic acid 4 using beef liver glutamate dehydrogenase. The cofactor NADH required for this reaction was regenerated using glucose dehydrogenase from Bacillus sp. A reaction yield of 80% and e.e. of 99.5% were obtained for L-6-hydroxynorleucine 3. To avoid the lengthy chemical synthesis of the ketoacid, a second route was developed in which racemic 6-hydroxynorleucine [readily available from hydrolysis of 5-(4-hydroxybutyl) hydantoin 5] was treated with D-amino acid oxidase from Trigonopsis variabilis to selectively convert the D-isomer of racemic 6-hydroxynorleucine to 2-keto-6-hydroxyhexanoic acid 4 and L-6-hydroxynorleucine 3. Subsequently, the 2-keto-6-hydroxyhexanoic acid 4 was converted to L-6-hydroxynorleucine by reductive amination using glutamate dehydrogenase. A reaction yield of 98% and an e.e. of 99.5% were obtained.
- Patel, Ramesh N.
-
p. 1275 - 1281
(2007/10/03)
-
- Aminodiol HIV Protease Inhibitors. 1. Design, Synthesis, and Preliminary SAR
-
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.
-
p. 1758 - 1768
(2007/10/02)
-
