69-65-8Relevant articles and documents
Stelliosphaerols A and B, Sesquiterpene-Polyol Conjugates from an Ecuadorian Fungal Endophyte
Forcina, Giovanni C.,Castro, Amaya,Bokesch, Heidi R.,Spakowicz, Daniel J.,Legaspi, Michelle E.,Kucera, Kaury,Villota, Stephany,Narvez-Trujillo, Alexandra,McMahon, James B.,Gustafson, Kirk R.,Strobel, Scott A.
, p. 3005 - 3010 (2015)
Endophytic fungi are plant tissue-associated fungi that represent a rich resource of unexplored biological and chemical diversity. As part of an ongoing effort to characterize Amazon rainforest-derived endophytes, numerous fungi were isolated and cultured from plants collected in the Yasun National Park in Ecuador. Of these samples, phylogenetic and morphological data revealed a previously undescribed fungus in the order Pleosporales that was cultured from the tropical tree Duroia hirsuta. Extracts from this fungal isolate displayed activity against Staphylococcus aureus and were thus subjected to detailed chemical studies. Two compounds with modest antibacterial activity were isolated, and their structures were elucidated using a combination of NMR spectroscopic analysis, LC-MS studies, and chemical degradation. These efforts led to the identification of stelliosphaerols A (1) and B (2), new sesquiterpene-polyol conjugates that are responsible, at least in part, for the S. aureus inhibitory activity of the fungal extract.
Rapid, one pot preparation of D-mannose and D-mannitol from starch: The effect of microwave irradiation and MoVI catalyst
Hricoviniova, Zuzana
, p. 1184 - 1188 (2011)
The effect of microwave irradiation upon starch hydrolysis and simultaneous epimerization of the D-glucose to D-mannose obtained was investigated. An acidic aqueous solution of starch was treated with a catalytic amount of hexavalent molybdenum salt in microwave field and the composition of the reaction mixture was analyzed. Rapid starch hydrolysis and subsequent epimerization provided an equilibrium reaction mixture of D-glucose and D-mannose (2:1) without the formation of any undesirable by-products. The reduction of D-mannose with sodium borohydride yielded D-mannitol in very good yield. Microwave irradiation proved to be an efficient tool for the transformation of starch to mannose over an MoVI catalyst. This method has the advantages of environmental friendliness, easy operation, good yields and substantial reduction of reaction time.
Seven new drimane-type sesquiterpenoids from a marine-derived fungus paraconiothyrium sporulosum YK-03
Zhang, Li-Hua,Chen, Gang,Sun, Yi,Wang, Hai-Feng,Bai, Jiao,Hua, Hui-Ming,Pei, Yue-Hu
, (2019)
Seven new drimane-type sesquiterpenoids, namely the sporulositols A-D (1-4), 6-hydroxydiaporol (5), seco-sporulositol (6) and sporuloside (7) were isolated from the ethyl acetate extract of fermentation broth for a marine-derived fungus Paraconiothyrium sporulosum YK-03. Their structureswere elucidated by analysis of extensive spectroscopic data, and the absolute configurations were established by crystal X-ray diffraction analysis and comparisons of circular dichroism data. Among them, sporulositols A-E (1-4) and seco-sporulositol (6) represent the first five examples of a unique class of drimanic mannitol derivatives, while compounds 6 and 7 may represent two new series of natural drimanes, possessing an aromatic ring with a rare 4,5-secodrimanic skeleton and an unusual CH3-15 rearranged drimanic α-D-glucopyranside, respectively. Furthermore, the origin of mannitol moiety was investigated by reliable HPLC and NMR analyses.
Iridoid and phenylethanoid glucosides from veronica lavaudiana
Taskova, Rilka M.,Kokubun, Tetsuo,Ryan, Ken G.,Garnock-Jones, Phil J.,Jensen, Soren R.
, p. 1477 - 1483 (2011)
From an extract of Veronica (sect. Hebe) lavaudiana we have identified mannitol and isolated 11 iridoid glucosides, the carbohydrate ester hebitol II, and four phenylethanoid glycoside esters. Five of the iridoid glycosides are new; of these, lavaudiosides A, B, and C (2a, 3a, and 4) are 1-mannityl esters of 8-epiloganic acid, while 7e and 7f are 6′-O-caffeoyl derivatives of catalpol. The new phenylethanoid glycoside esters, heliosides A, B, and C (8b - d), are 6′-xylosyl derivatives of aragoside. The structures of the new compounds were elucidated mainly by spectroscopic analysis, but also by chemical degradation. We also demonstrated that the structures of the known glycosides globularitol and hebitols I and II should be revised. These compounds are derivatives of mannitol and not glucitol as previously believed.
Selective hydrogenation of d-mannose to d-mannitol using NiO-modified TiO2 (NiO-TiO2) supported ruthenium catalyst
Mishra, Dinesh Kumar,Hwang, Jin-Soo
, p. 13 - 19 (2013)
NiO-modified TiO2 (NiO-TiO2) supported ruthenium catalyst Ru/(NiO-TiO2) is prepared by simple impregnation method and characterized by using energy dispersive X-ray analysis (EDX/EDS), temperature- programmed reduction (TPR), inductively coupled plasma (ICP) mass spectrometry, transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and CO chemisorption. The catalyst Ru/(NiO-TiO2) is evaluated in d-mannose hydrogenation and hydrogenation experiments to produce a selective product d-mannitol were carried out batch wise in a three-phase laboratory scale reactor. A tentative mechanism for reduction of d-mannose is presented. The kinetics of d-mannose hydrogenation to d-mannitol using catalyst Ru/(NiO-TiO2) was studied. The kinetic data were modeled by zero, first and second-order reaction equations. A set of four experiments was also carried out to test the deactivation of the catalyst. For affording maximum d-mannose conversion, yield and selectivity to d-mannitol, the reaction conditions are optimized.
Selective and Scalable Synthesis of Sugar Alcohols by Homogeneous Asymmetric Hydrogenation of Unprotected Ketoses
Tindall, Daniel J.,Mader, Steffen,Kindler, Alois,Rominger, Frank,Hashmi, A. Stephen K.,Schaub, Thomas
supporting information, p. 721 - 725 (2020/10/19)
Sugar alcohols are of great importance for the food industry and are promising building blocks for bio-based polymers. Industrially, they are produced by heterogeneous hydrogenation of sugars with H2, usually with none to low stereoselectivities. Now, we present a homogeneous system based on commercially available components, which not only increases the overall yield, but also allows a wide range of unprotected ketoses to be diastereoselectively hydrogenated. Furthermore, the system is reliable on a multi-gram scale allowing sugar alcohols to be isolated in large quantities at high atom economy.
Product Control and Insight into Conversion of C6 Aldose Toward C2, C4 and C6 Alditols in One-Pot Retro-Aldol Condensation and Hydrogenation Processes
Gao, Lou,Hou, Wenrong,Hui, Yingshuang,Tang, Yi,Zhan, Yulu,Zhang, Yahong
, p. 560 - 566 (2021/06/25)
Alcohols have a wide range of applicability, and their functions vary with the carbon numbers. C6 and C4 alditols are alternative of sweetener, as well as significant pharmaceutical and chemical intermediates, which are mainly obtained through the fermentation of microorganism currently. Similarly, as a bulk chemical, C2 alditol plays a decisive role in chemical synthesis. However, among them, few works have been focused on the chemical production of C4 alditol yet due to its difficult accumulation. In this paper, under a static and semi-flowing procedure, we have achieved the product control during the conversion of C6 aldose toward C6 alditol, C4 alditol and C2 alditol, respectively. About C4 alditol yield of 20 % and C4 plus C6 alditols yield of 60 % are acquired in the one-pot conversion via a cascade retro-aldol condensation and hydrogenation process. Furthermore, in the semi-flowing condition, the yield of ethylene glycol is up to 73 % thanks to its low instantaneous concentration.
Glycosides from Buddleja officinalis with their protective effects on photoreceptor cells in light-damaged mouse retinas
Chen, Yu,Du, Xiaoye,Jia, Qi,Li, Bo,Li, Yiming,Long, Zehai,Wang, Qiyao,Xu, Zhijian,Zhang, Yong,Zhu, Weiliang
, (2021/07/06)
A new phenylethanoid, hebitol IV (1), along with fifteen known glycosides (2-16), were isolated from water extract of the flower buds of Buddleja officinalis. Their structures were elucidated on the basis of 1 D-NMR, 2 D-NMR and MS data. Molecular docking showed the potential activities of the natural products against VEGFR-2. Bioassay results revealed that the compounds 10 and 14 exhibited strong inhibitory activity against VEGFR-2 with IC50 values of 0.51 and 0.32 μM, respectively. Moreover, the potential retinal protective effects of 10 and 14 were then investigated in the mouse model featuring bright light-induced retinal degeneration. The results demonstrated remarkable photoreceptor protective activities of 10 and 14in?vivo.
Efficient Synthesis of Sugar Alcohols over a Synergistic and Sustainable Catalyst
Lin, Lu,Qiu, Jiarong,Sun, Yong,Tang, Xing,Zeng, Xianhai,Zhang, Liangqing
, p. 2467 - 2476 (2021/07/16)
A series of catalysts were prepared for sugar alcohols production to overcome the deficiencies of the previous reported catalysts, such as low yield of sugar alcohols, single function, instability, and controversial role of active sites. The role of each metal and their synergistic-cooperation was discussed in detail with a combination of conditional experiments and characterizations. The results indicated that bifunctional Ni6.66Fe1Al1.55 catalyst has unique structure with superparamagnetism and excellent activity. The (111) and (200) planes of metallic Ni are the hydrogenation active phases and preferentially exposed on Ni-Al-Ox spinel. The desired arabitol or mannitol was obtained by tuning the ratio of Br?nsted and Lewis acid sites. The recycling tests indicated that the unique structure of the prepared Ni-based catalyst can suppress leaching and poisoning, which has high textural stability and activity.
Elucidating the effect of solid base on the hydrogenation of C5 and C6 sugars over Pt–Sn bimetallic catalyst at room temperature
Tathod, Anup P.,Dhepe, Paresh L.
, (2021/05/19)
Conversion of sugars into sugar alcohols at room temperature with exceedingly high yields are achieved over Pt–Sn/γ-Al2O3 catalyst in the presence of calcined hydrotalcite. pH of the reaction mixture significantly affects the conversion and selectivity for sugar alcohols. Selection of a suitable base is the key to achieve optimum yields. Various solid bases in combination with Pt–Sn/γ-Al2O3 catalysts were evaluated for hydrogenation of sugars. Amongst all combinations, the mixture (1:1 wt/wt) of Pt–Sn/γ-Al2O3 and calcined hydrotalcite showed the best results. Hydrotalcite helps to make the pH of reaction mixture alkaline at which sugar molecules undergo ring opening. The sugar molecule in open chain form has carbonyl group which can be polarized by Sn in Pt–Sn/γ-Al2O3 and Pt facilitates the hydrogenation. In the current work, effect of both; solid base and Sn as a promoter has been studied to improve the yields of sugar alcohols from various C5 and C6 sugars at very mild reaction conditions.
