85550-19-2Relevant academic research and scientific papers
Immobilized lipase screening towards continuous-flow kinetic resolution of (±)-1,2-propanediol
Aguillón, Anderson R.,Avelar, Marcelo N.,Gotardo, Larissa E.,de Souza, Stefania P.,Le?o, Raquel A.C.,Itabaiana, Ivaldo,Miranda, Leandro S.M.,de Souza, Rodrigo O.M.A.
, p. 128 - 134 (2019/02/12)
Here, we report a flow chemistry approach for kinetic resolution of (±)-1,2-propanediol protected by trityl group using the packed-bed reactor filled with different immobilized enzymes. It was investigated the performance of 16 immobilized lipases, includ
Continuous-Flow Synthesis of (R)-Propylene Carbonate: An Important Intermediate in the Synthesis of Tenofovir
Suveges, Nicolas S.,Rodriguez, Anderson A.,Diederichs, Carla C.,de Souza, Stefania P.,Le?o, Raquel A. C.,Miranda, Leandro S. M.,Horta, Bruno A. C.,Pedraza, Sérgio F.,de Carvalho, Otavio V.,Pais, Karla C.,Terra, José H. C.,de Souza, Rodrigo O. M. A.
, p. 2931 - 2938 (2018/06/27)
(R)-Propylene carbonate is an important intermediate in the synthesis of tenofovir pro-drugs such as tenofovir alafenamide fumarate (TAF) and tenofovir diisoproyl fumarate (TDF). Independent of the pro-drug type, tenofovir presents a chiral secondary hydroxy derivative, which can be obtained directly from (R)-propylene carbonate. Herein, we report our chemo-enzymatic continuous-flow strategy towards (R)-propylene carbonate starting from a very cheap and renewable raw material, glycerol. We were able to synthesize (R)-propylene carbonate in seven continuous-flow steps, starting from glycerol, in good-to-excellent yields (66–93 %) and excellent selectivity (E > 200).
Resolution of a racemic 1,2-diol using triphenylmethyl protection of the primary hydroxyl group and Mucor miehei lipase (Lipozyme) for the kinetic resolution
Petursson, Sigthor,Jonsdottir, Sigridur
experimental part, p. 1809 - 1812 (2012/01/13)
The triphenylmethyl group gives very simple access to the 1-protection of 1,2-diol as exemplified by racemic propane-1,2-diol. This group has, however, been shown to be incompatible with lipases commonly used for the resolution of alcohols. This turned out to be the case for Pseudomonas cepacia lipase, which we have used in our earlier work. Lipozyme, a Mucor miehei lipase, best known for 1,3-selectivity with glycerol is, however, shown to catalyze transacetylation onto the secondary hydroxyl group next to a triphenylmethoxy group. The transacetylation is completely enantioselective for the (R)-enantiomer giving a very simple method for the resolution of this type of 1,2-diol enantiomer.
Helical and flat structures from chiral dendronized rectangular oligo(phenylene ethynylene)s
Garcia, Fatima,Aparicio, Fatima,Marenchino, Marco,Campos-Olivas, Ramon,Sanchez, Luis
supporting information; experimental part, p. 4264 - 4267 (2010/11/16)
Figure Presented. The synthesis of two chiral amphiphiles and their self-assembling features in solution and onto surfaces is reported. The different degree of interdigitation of the paraffinic substituents has an enormous influence in the chirality of the aggregates. Thus, while oligo(phenylene ethynylene) 1 shows a bisignated Cotton effect in solution and P-type helices onto surfaces, compound 2 lacks in any dichroic response at room temperature and self-assembles into flat ribbons.
Molecular structure of helical supramolecular dendrimers
Peterca, Mihai,Percec, Virgil,Imam, Mohammad R.,Leowanawat, Pawaret,Morimitsu, Kentaro,Heiney, Paul A.
supporting information; body text, p. 14840 - 14852 (2009/02/08)
The molecular structure of helical supramolecular dendrimers generated from self-assembling dendrons and dendrimers and from self-organizable dendronized polymers was elucidated for the first time by the simulation of the X-ray diffraction patterns of their oriented fibers. These simulations were based on helical diffraction theory applied to simplified atomic helical models, followed by Cerius2 calculations based on their complete molecular helical structures. Hundreds of samples were screened until a library containing 14 supramolecular dendrimers and dendronized polymers provided a sufficient number of helical features in the X-ray diffraction pattern of their oriented fibers. This combination of techniques provided examples of single-92 and -11 3 helices, triple-61, -81, -91, and -121 helices, and an octa-321 helix that were assembled from crownlike dendrimers, hollow and nonhollow supramolecular crownlike dendrimers, hollow and nonhollow supramolecular disklike dendrimers, and hollow and nonhollow supramolecular and macromolecular helicene-like architectures. The method elaborated here for the determination of the molecular helix structure was transplanted from the field of structural biology and will be applicable to other classes of synthetic helical assemblies. The determination of the molecular structure of helical supramolecular assemblies is expected to provide an additional level of precision in the design of helical functional assemblies resembling those from biological systems.
Self-assembling phenylpropyl ether dendronized helical polyphenylacetylenes
Percec, Virgil,Peterca, Mihai,Rudick, Jonathan G.,Aqad, Emad,Imam, Mohammad R.,Heiney, Paul A.
, p. 9572 - 9581 (2008/12/20)
The first example of a self-assembling phenylpropyl ether based dendronized polymer has been reported and its preferred helical handedness has been determined. Dendronized polymer poly(10) and its nondendritic analogue poly(8) are high-cis-content polyphenylacetylenes (PPAs) prepared by using [Rh(nbd)Cl]2/NEt3 (nbd: 2,5-nor-bornadiene). Both polymers possess a Stereocenter in their side chain, which selects a preferred helical handedness.Based on negative exciton chirality observed in the CD spectra of poly(10), we have designated this molecule as a right-handed helical polymer, which persists over a wide temperature range. Poly(10) self-organizes into both ΦhiO and Φh lattices in bulk. The ΦhiO-to-Φh transition is associated with thermore-versible cis-cisoidal to cis-transoidal isomerization of the helical PPA, accompanied by a dramatic decrease in the column diameter and a decrease in the π-stacking correlation length along the column. A model for the right-handed helical dendronized PPA has been proposed wherein dendrons from adjacent column strata interdigitate to effectively fill space.
METHOD OF PREPARATION OF OPTICALLY ACTIVE ALCOHOLS
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Page/Page column 16, (2010/02/10)
The present invention relates to a method for preparing chiral alcohol having optical activity. More specifically, the present invention relates to a method for preparing (S)-chiral alcohol with a high yield and a high optical purity by mixing achiral substrates such as racemic alcohol or ketone with metal catalyst and protein hydrolase to perform a dynamic kinetic resolution reaction.
Aminocyclopentadienyl Ruthenium Complexes as Racemization Catalysts for Dynamic Kinetic Resolution of Secondary Alcohols at Ambient Temperature
Choi, Jun Ho,Choi, Yoon Kyung,Kim, Yu Hwan,Park, Eun Sil,Kim, Eun Jung,Kim, Mahn-Joo,Park, Jaiwook
, p. 1972 - 1977 (2007/10/03)
Aminocyclopentadienyl ruthenium complexes, which can be used as room-temperature racemization catalysts with lipases in the dynamic kinetic resolution (DKR) of secondary alcohols, were synthesized from cyclopenta-2,4-dienimines, Ru3(CO)12, and CHCl 3: [2,3,4,5-Ph4(η5-C 4CNHR)]Ru-(CO)2Cl (4: R = i-Pr; 5: R = n-Pr; 6: R = t-Bu), [2,5-Me2-3,4-Ph2(η5-C 4CNHR)]Ru(CO)2Cl (7: R = i-Pr; 8: R = Ph), and [2,3,4,5-Ph4(η5-C4CNHAr)]Ru(CO) 2Cl (9: Ar =p-NO2C6H4; 10: Ar = p-ClC6H4; 11: Ar = Ph; 12: Ar = p-OMeC6H 4; 13: Ar = p-NMe2C6H4). The tests in the racemization of (S)-4-phenyl-2-butanol showed that 7 is the most active catalyst, although the difference decreased in the DKR. Complex 4 was used in the DKR of various alcohols; at room temperature, not only simple alcohols but also functionalized ones such as allylic alcohols, alkynyl alcohols, diols, hydroxyl esters, and chlorohydrins were successfully transformed to chiral acetates. In mechanistic studies for the catalytic racemization, ruthenium hydride 14 appeared to be a key species. It was the major organometallic species in the racemization of (S)-1-phenylethanol with 4 and potassium tert-butoxide. In a separate experiment, (S)-1-phenylethanol was racemized catalytically by 14 in the presence of acetophenone.
Macrocyclic bisindolylmaleimides: Synthesis by inter- and intramolecular alkylation
Faul, Margaret M.,Winneroski, Leonard L.,Krumrich, Christine A.,Sullivan, Kevin A.,Gillig, James R.,Neel, David A.,Rito, Christopher J.,Jirousek, Michael R.
, p. 1961 - 1973 (2007/10/03)
Macrocyclic bisindolylmaleimides 1-4 have been identified as competitive reversible inhibitors of PKC β1 and β2 and are being advanced to the clinic for evaluation as a treatment of retinopathy associated with diabetic complications. Highly convergent and stereoselective syntheses of 1-4 have been developed. The key synthetic step involves intermolecular alkylation of symmetrical bisindolylmaleimide 9 with chiral bisalkylating agent 8c and is amenable to the preparation of multikilogram quantities of these compounds. The synthetic sequence to 1, the most active the compound, proceeds in 11 steps and 26% overall yield (> 98% ee) from (R)-1-chloro-2,3-propanediol. No chromatographic purifications are required throughout the process and the final product is isolated in >97% purity after crystallization from DMF/MeOH. Synthesis of 1-4 by intramolecular alkylation proved less efficient, requiring 17 steps and affording 1-4 in lower overall yields of 6.0-8.5%.
Improved Synthesis of (-)-(2R,6R)-2,6-Dimethylmorpholine
Licandro, Emanuela,Maiorana, Stefano,Manzotti, Raffaella,Papagni, Antonio,Pryce, Mary,et al.
, p. 815 - 818 (2007/10/03)
An improved procedure for obtaining the enantiomerically pure title amine is described, using a convergent synthesis, starting from the easily available (R)- and (S)-1,2-propanediols.
