124-76-5Relevant articles and documents
Simple Plug-In Synthetic Step for the Synthesis of (?)-Camphor from Renewable Starting Materials
Calderini, Elia,Drienovská, Ivana,Myrtollari, Kamela,Pressnig, Michaela,Sieber, Volker,Schwab, Helmut,Hofer, Michael,Kourist, Robert
, p. 2951 - 2956 (2021/06/18)
Racemic camphor and isoborneol are readily available as industrial side products, whereas (1R)-camphor is available from natural sources. Optically pure (1S)-camphor, however, is much more difficult to obtain. The synthesis of racemic camphor from α-pinene proceeds via an intermediary racemic isobornyl ester, which is then hydrolyzed and oxidized to give camphor. We reasoned that enantioselective hydrolysis of isobornyl esters would give facile access to optically pure isoborneol and camphor isomers, respectively. While screening of a set of commercial lipases and esterases in the kinetic resolution of racemic monoterpenols did not lead to the identification of any enantioselective enzymes, the cephalosporin Esterase B from Burkholderia gladioli (EstB) and Esterase C (EstC) from Rhodococcus rhodochrous showed outstanding enantioselectivity (E>100) towards the butyryl esters of isoborneol, borneol and fenchol. The enantioselectivity was higher with increasing chain length of the acyl moiety of the substrate. The kinetic resolution of isobornyl butyrate can be easily integrated into the production of camphor from α-pinene and thus allows the facile synthesis of optically pure monoterpenols from a renewable side-product.
Enantioselective Construction of Modular and Asymmetric Baskets
Badji?, Jovica D.,Finnegan, Tyler J.,Gunther, Michael J.,Pavlovi?, Radoslav Z.,Wang, Xiuze
supporting information, p. 25075 - 25081 (2021/10/25)
The precise positioning of functional groups about the inner space of abiotic hosts is a challenging task and of interest for developing more effective receptors and catalysts akin to those found in nature. To address it, we herein report a synthetic methodology for preparing basket-like cavitands comprised of three different aromatics as side arms with orthogonal esters at the rim for further functionalization. First, enantioenriched A (borochloronorbornene), B (iodobromonorbornene), and C (boronorbornene) building blocks were obtained by stereoselective syntheses. Second, consecutive A-to-B and then AB-to-C Suzuki–Miyaura (SM) couplings were optimized to give enantioenriched ABC cavitand as the principal product. The robust synthetic protocol allowed us to prepare (a) an enantioenriched basket with three benzene sides and each holding either tBu, Et, or Me esters, (b) both enantiomers of a so-called “spiral staircase” basket with benzene, naphthalene, and anthracene groups surrounding the inner space, and (c) a photo-responsive basket bearing one anthracene and two benzene arms.
Monoterpenoid-based inhibitors of filoviruses targeting the glycoprotein-mediated entry process
Baev, Dmitriy S.,Maksyutov, Rinat A.,Mordvinova, Ekaterina D.,Pyankov, Oleg V.,Salakhutdinov, Nariman F.,Shcherbakov, Dmitriy N.,Shcherbakova, Nadezhda S.,Sokolova, Anastasiya S.,Tolstikova, Tatyana G.,Yarovaya, Olga I.,Zaykovskaya, Anna V.,Zybkina, Anastasiya V.
, (2020/09/09)
In this study, we screened a large library of (+)-camphor and (?)-borneol derivatives to assess their filovirus entry inhibition activities using pseudotype systems. Structure-activity relationship studies revealed several compounds exhibiting submicromolar IC50 values. These compounds were evaluated for their effect against natural Ebola virus (EBOV) and Marburg virus. Compound 3b (As-358) exhibited the good antiviral potency (IC50 = 3.7 μM, SI = 118) against Marburg virus, while the hydrochloride salt of this compound 3b·HCl had a strong inhibitory effect against Ebola virus (IC50 = 9.1 μM, SI = 31) and good in vivo safety (LD50 > 1000 mg/kg). The results of molecular docking and in vitro mutagenesis analyses suggest that the synthesized compounds bind to the active binding site of EBOV glycoprotein similar to the known inhibitor toremifene.
Molecular cloning and functional characterization of a two highly stereoselective borneol dehydrogenases from Salvia officinalis L
Drienovská, Ivana,Kolanovi?, Dajana,Chánique, Andrea,Sieber, Volker,Hofer, Michael,Kourist, Robert
, (2020/01/11)
Enzymes for selective terpene functionalization are of particular importance for industrial applications. Pure enantiomers of borneol and isoborneol are fragrant constituents of several essential oils and find frequent application in cosmetics and therapy. Racemic borneol can be easily obtained from racemic camphor, which in turn is readily available from industrial side-streams. Enantioselective biocatalysts for the selective conversion of borneol and isoborneol stereoisomers would be therefore highly desirable for their catalytic separation under mild reaction conditions. Although several borneol dehydrogenases from plants and bacteria have been reported, none show sufficient stereoselectivity. Despite Croteau et al. describing sage leaves to specifically oxidize one borneol enantiomer in the late 70s, no specific enzymes have been characterized. We expected that one or several alcohol dehydrogenases encoded in the recently elucidated genome of Salvia officinalis L. would, therefore, be stereoselective. This study thus reports the recombinant expression in E. coli and characterization of two enantiospecific enzymes from the Salvia officinalis L. genome, SoBDH1 and SoBDH2, and their comparison to other known ADHs. Both enzymes produce preferentially (+)-camphor from racemic borneol, but (?)-camphor from racemic isoborneol.
Hydrogen Sulfide: A Reagent for pH-Driven Bioinspired 1,2-Diol Mono-deoxygenation and Carbonyl Reduction in Water
Barata-Vallejo, Sebastián,Ferreri, Carla,Golding, Bernard T.,Chatgilialoglu, Chryssostomos
supporting information, p. 4290 - 4294 (2018/07/29)
Hydrogen sulfide (H2S) was evaluated for its peculiar sulfur radical species generated at different pHs and was used under photolytical conditions in aqueous medium for the reduction of 1,2-diols to alcohols. The conversion steps of 1,2-cyclopentanediol to cyclopentanol via cyclopentanone were analyzed, and it was proven that the reaction proceeds via a dual catalytic/radical chain mechanism. This approach was successfully adapted to the reduction of a variety of carbonyl compounds using H2S at pH 9 in water. This work opens up the field of environmental friendly synthetic processes using the pH-driven modulation of reactivity of this simple reagent in water.
Preparation method of D-borneol
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Paragraph 0032; 0033; 0037; 0042; 0046, (2018/11/22)
The invention relates to a preparation method of D-borneol. The method comprises the following steps: ensuring that natural camphor is reacted for 1 to 8 hours at 0 to 40 DEG C under the existence ofan organic solvent and a chiral reagent (R)-BINAP-H serving as catalysts, and ensuring that the optimized ratio of the organic solvent to the chiral reagent (R)-BINAP-H to camphor is (10-30ml): (20-50mmol): 18mmol.
Reliable HPLC separation, vibrational circular dichroism spectra, and absolute configurations of isoborneol enantiomers
Gao, Rui-Qi,Fan, Jun,Tan, Qi,Guo, Dong,Chen, Tao,He, Ru-Jian,Li, Dan,Zhang, Hui,Zhang, Wei-Guang
, p. 550 - 557 (2017/08/26)
Resolution of chiral compounds has played an important role in the pharmaceutical field, involving detailed studies of pharmacokinetics, physiological, toxicological, and metabolic activities of enantiomers. Herein, a reliable method by high-performance liquid chromatography (HPLC) coupled with an optical rotation detector was developed to separate isoborneol enantiomers. A cellulose tris(3, 5-dimethylphenylcarbamate)-coated chiral stationary phase showed the best separation performance for isoborneol enantiomers in the normal phase among four polysaccharide chiral packings. The effects of alcoholic modifiers and column temperature were studied in detail. Resolution of the isoborneol racemate displayed a downward trend along with an increase in the content of ethanol and column temperature, indicating that less ethanol in the mobile phase and lower temperature were favorable to this process. Moreover, two isoborneol enantiomers were obtained via a semipreparative chiral HPLC technique under optimum conditions, and further characterized by analytical HPLC, and experimental and calculated vibrational circular dichroism (VCD) spectroscopy, respectively. The solution VCD spectrum of the first-eluted component was consistent with the Density Functional Theory (DFT) calculated pattern based on the SSS configuration, indicating that this enantiomer should be (1S, 2S, 4S)-(+)-isoborneol. Briefly, these results have provided reliable information to establish a method for analysis, preparative separation, and absolute configuration of chiral compounds without typical chromophoric groups.
An efficient FeCl3-mediated approach for reduction of ketones through N-heterocyclic carbene boranes
Wang, Ming-Hui,Chen, Ling-Yan
supporting information, p. 732 - 735 (2017/03/31)
An efficient FeCl3-mediated approach for reduction of ketones by NHC-BH3 has been developed. A series of ketones were smoothly converted to the corresponding alcohols in good to excellent yields through NHC-BH3 reductive process.
A saponified the ester is continual isoborneol acetate method of preparing isoborneol
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Paragraph 0043-0051, (2017/01/19)
The invention discloses a method for preparing isoborneol by continuous saponification of isobornyl acetate. The method comprises the following steps: saponifying sodium hydroxide and isobornyl acetate as raw materials, rectifying, layering, washing with water, crystallizing and the like to prepare white isoborneol crystals. The saponification reaction of isobornyl acetate can be continuously carried out in an oscillatory flow reactor, a static mixer or an ultrasonic mixer; a polar solvent is added in the reaction, so that the saponification reaction is heterogeneously carried out, the reaction time can be shortened, the reaction temperature can be reduced, the conversion rate of isobornyl acetate is more than 99%, and the product yield is more than 95%. The method is low in production energy consumption and high in product yield.
An unexpected reaction of camphor with sodium metal
Khanvilkar, Aditya N.,Gupta, Riddhi,Bedekar, Ashutosh V.
, p. 1327 - 1331 (2016/02/23)
Reaction of camphor with sodium metal at elevated temperature in refluxing THF or toluene, furnishes an unexpected product. The product has been identified by spectral analysis and its structure confirmed by single crystal X-ray diffraction study. A preliminary mechanistic explanation has been suggested to explain this reaction.
