- Asymmetric hydrolysis of styrene oxide by PvEH2, a novel Phaseolus vulgaris epoxide hydrolase with extremely high enantioselectivity and regioselectivity
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A novel EH from Phaseolus vulgaris, PvEH2, was discovered based on the computer-aided analysis, and its encoding gene was cloned and expressed in E. coli Rossetta (DE3). The substrate spectrum of recombinant (re) PvEH2 was assayed, among which the enantiomeric ratio of rePvEH2 towards racemic styrene oxide (rac-1a) was > 200, while its regioselectivity coefficients, αS and βR, towards (S)- and (R)-1a were 99.1 and 69.8%, respectively. The asymmetric hydrolysis of 20 mM rac-1a by rePvEH2-expressing whole cells was performed at 25 °C, retaining (R)-1a with > 99.5% ees and 49.4% yield and producing (R)-phenyl-1,2-ethanediol (1b) with 96.2% eep and 49.7% yield in 40 min.
- Li, Chuang,Hu, Die,Zong, Xun-Cheng,Deng, Chao,Feng, Lei,Wu, Min-Chen,Li, Jian-Fang
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Read Online
- Enantioconvergent hydrolysis of styrene epoxides by newly discovered epoxide hydrolases in mung bean
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Two novel epoxide hydrolases were discovered in mung bean (Phaseolus radiatus L.) for the first time, either of which can catalyze enantioconvergent hydrolysis of styrene epoxides. Their regioselectivity coefficients are more than 90% for the p-nitrostyrene oxide. Furthermore, the crude mung bean powder was also shown to be a cheap and practical biocatalyst, allowing a one-step asymmetric synthesis of chiral (R)-diols from racemic epoxides, in up to >99% ee and 68.7% overall yield (after recrystallization).
- Xu, Wei,Xu, Jian-He,Pan, Jiang,Gu, Qing,Wu, Xin-Yan
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Read Online
- Lewis Base Catalyzed Dioxygenation of Olefins with Hypervalent Iodine Reagents
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1,2-Diols are extremely useful building blocks in organic synthesis. Hypervalent iodine reagents are useful for the vicinal dihydroxylation of olefins to give 1,2-diols under metal-free conditions, but strongly acidic promoters are often required. Herein, we report a catalytic vicinal dioxygenation of olefins with hypervalent iodine reagents using Lewis bases as catalysts. The conditions are mild and compatible with various functional groups.
- Pan, Liangkun,Ke, Zhihai,Yeung, Ying-Yeung
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p. 8174 - 8178
(2021/10/25)
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- Silver(I)-Catalyzed Widely Applicable Aerobic 1,2-Diol Oxidative Cleavage
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The oxidative cleavage of 1,2-diols is a fundamental organic transformation. The stoichiometric oxidants that are still predominantly used for such oxidative cleavage, such as H5IO6, Pb(OAc)4, and KMnO4, generate stoichiometric hazardous waste. Herein, we describe a widely applicable and highly selective silver(I)-catalyzed oxidative cleavage of 1,2-diols that consumes atmospheric oxygen as the sole oxidant, thus serving as a potentially greener alternative to the classical transformations.
- Zhou, Zhong-Zhen,Liu, Mingxin,Lv, Leiyang,Li, Chao-Jun
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supporting information
p. 2616 - 2620
(2018/02/13)
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- Metal-free dihydroxylation of alkenes using cyclobutane malonoyl peroxide
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Cyclobutane malonoyl peroxide (7), prepared in a single step from the commercially available diacid 6, is an effective reagent for the dihydroxylation of alkenes. Reaction of a chloroform solution of 7 with an alkene in the presence of 1 equiv of water at 40 °C followed by alkaline hydrolysis leads to the corresponding diol (30-84%). With 1,2-disubstituted alkenes, the reaction proceeds with syn-selectivity (3:1 → 50:1). A mechanism consistent with experimental findings is proposed, which is supported by deuterium and oxygen labeling studies and explains the stereoselectivity observed. Alternative reaction pathways that are dependent on the structure of the starting alkene are also described leading to the synthesis of allylic alcohols and γ-lactones.
- Jones, Kevin M.,Tomkinson, Nicholas C. O.
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experimental part
p. 921 - 928
(2012/02/16)
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- One-pot synthesis of enantiomerically pure 1, 2-diols: Asymmetric reduction of aromatic α-oxoaldehydes catalysed by Candida parapsilosis ATCC 7330
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A facile and simple one-pot method was developed to produce a series of optically active (S)-1-phenyl-1,2-ethanediols with good yields (up to 70%) and high enantiomeric excess (>99%) via asymmetric reduction of various substituted aromatic α-oxoaldehydes using Candida parapsilosis ATCC 7330.
- Mahajabeen, Pula,Chadha, Anju
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p. 2156 - 2160
(2012/05/04)
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- Alkene syn dihydroxylation with malonoyl peroxides
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Cyclopropyl malonoyl peroxide (1), which can be prepared in a single step from the commercially available diacid, is an effective reagent for the dihydroxylation of alkenes. Reaction of 1 with an alkene in the presence of 1 equiv of water at 40 °C followed by alkaline hydrolysis leads to the corresponding diol (40-93%). With 1,2-disubstituted alkenes, the reaction proceeds with syn selectivity (3:1 to >50:1). A mechanism consistent with the experimental findings that is supported by oxygen-labeling studies is proposed.
- Griffith, James C.,Jones, Kevin M.,Picon, Sylvain,Rawling, Michael J.,Kariuki, Benson M.,Campbell, Matthew,Tomkinson, Nicholas C. O.
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supporting information; experimental part
p. 14409 - 14411
(2010/12/24)
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- ARYL-PHENYL-SULFONAMIDE-PHENYLENE COMPOUNDS AND THEIR USE
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The present invention pertains generally to the field of therapeutic compounds, and more specifically to certain aryl-phenyl-sulfonamido-phenylene compounds of the following formula (I) (collectively referred to herein as "APSAP compounds"). The present invention also pertains to pharmaceutical compositions comprising such compounds, and the use of such compounds and compositions, both in vitro and in vivo, in treatment, for example, of inflammation and/or joint destruction and/or bone loss; of disorders mediated by excessive and/or inappropriate and/or prolonged activation of the immune system; of inflammatory and autoimmune disorders, for example, rheumatoid arthritis, psoriasis, psoriatic arthritis, chronic obstructive pulmonary disease (COPD), atherosclerosis, inflammatory bowel disease, ankylosing spondylitis, and the like; of disorders associated with bone loss, such as bone loss associated with excessive osteoclast activity in rheumatoid arthritis, osteoporosis, cancer-associated bone disease, Paget's disease and the like, etc.; and of cancer, such as a haematological malignancy, a solid tumour, etc.
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Page/Page column 102
(2010/04/25)
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- Photochemistry of 2-nitrobenzylidene acetals
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(Figure Presented) Photolysis of dihydroxy compounds (diols) protected as 2-nitrobenzylidene acetals (ONBA) and subsequent acid- or base-catalyzed hydrolysis of the 2-nitrosobenzoic acid ester intermediates result in an efficient and high-yielding release of the substrates. We investigated the scope and limitations of ONBA photochemistry and expanded upon earlier described two-step procedures to show that the protected diols of many structural varieties can also be liberated in a one-pot procedure. In view of the fact that the acetals of nonsymmetrically substituted diols are converted into one of the corresponding 2-nitrosobenzoic acid ester isomers with moderate to high regioselectivity, the mechanism of their formation was studied using various experimental techniques. The experimental data were found to be in agreement with DFT-based quantum chemical calculations that showed the preferential cleavage occurs on the acetal C-O bond in the vicinity of more electron-withdrawing (or less electron-donating) groups. The study also revealed considerable complexity in the cleavage mechanism and that the structural variations in the substrate can significantly alter the reaction pathway. This deprotection strategy was found to be also applicable for 2-thioethanol when released from the corresponding monothioacetal in the presence of a reducing agent, such as ascorbic acid.
- Sebej, Peter,Solomek, Tomas,Hroudna, L'ubica,Brancova, Pavla,Klan, Petr
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experimental part
p. 8647 - 8658
(2010/02/28)
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- A rapid 1,2-dihydroxylation of alkenes using a lipase and hydrogen peroxide under microwave conditions
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The combined advantages of using an enzyme immobilized lipase from Pseudomonas sp [PSLG6], hydrogen peroxide, ethyl acetate and microwave irradiation for the dihydroxylation of olefins are reported.
- Sarma, Kuladip,Borthakur, Naleen,Goswami, Amrit
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p. 6776 - 6778
(2008/02/13)
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- New uses for the Burgess reagent in chemical synthesis: Methods for the facile and stereoselective formation of sulfamidates, glycosylamines, and sulfamides
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Although the Burgess reagent (methoxycarbonylsulfamoyltriethylammonium hydroxide, inner salt) has found significant use in chemical synthesis as a dehydrating agent, almost no work has been directed towards its potential in other synthetic applications. As this article will detail, we have found that the Burgess reagent is remarkably effective at accomplishing a number of non-dehydrative synthetic tasks when applied to appropriate substrates, such as the formation of sulfamidates from 1,2-diols or epoxyalcohols, α- and β-glycosylamines from carbohydrates, and cyclic sulfamides from 1,2-aminoalcohols. Beyond delineating the power of these new reaction manifolds, we also describe the construction of a group of alternative Burgess-type reagents that extends the scope of these new reactions even further.
- Nicolaou,Snyder, Scott A.,Longbottom, Deborah A.,Nalbandian, Annie Z.,Huang, Xianhai
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p. 5581 - 5606
(2007/10/03)
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- N-phenyl-N-acetamidoglycinamides, their preparation and medicaments containing them
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Compounds of formula: STR1 in which R1 represents a hydrogen atom or an alkyl, alkoxycarbonyl or an unsubstituted or substituted phenyl radical, R2 represents a hydrogen atom or an unsubstituted or substituted alkyl radical, R3 represents an alkyl, phenylalkyl, indanyl, cycloalkylalkyl or an unsubstituted or substituted phenyl radical, or R2 and R3 form a heterocycle together with the nitrogen atom to which they are attached, and R4 represents an unsubstituted or substituted phenyl radical, a naphthyl, indolyl or quinolyl radical or a phenylamino radical in which the phenyl ring is unsubstituted or substituted, their preparation and medicaments containing them.
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