An Efficient Synthesis of 5,5′-(Tetradecane-1,14-diyl)bis(2-methylbenzene-1,3-diol) and Related Substances

1997 ◽  
Vol 50 (7) ◽  
pp. 747 ◽  
Author(s):  
Van H. Tran ◽  
Basil D. Roufogalis ◽  
Colin C. Duke
Keyword(s):  
Minor Component ◽  
High Yield ◽  
Efficient Synthesis ◽  
Related Substances ◽  
Other Substances ◽  
A Minor

An efficient and versatile method was developed to synthesize 5,5′-(tetradecane-1,14-diyl)bis(2-methylbenzene-1,3-diol) (striatol), a minor component of the plant Grevillea striata (Proteaceae family). Other substances prepared in high yield by the method include 5,5′-(dodecane-1,12-diyl)bis(2-methylbenzene-1,3-diol), 5,5′-(decane-1,10-diyl)bis(2-methylbenzene-1,3-diol), 5,5′-(octane-1,8-diyl)bis(2-methylbenzene-1,3-diol) and 2-methyl-5-nonylresorcinol

Purification strategy

2001 ◽  
Author(s):  
Simon D. Roe
Keyword(s):  
Protein Purification ◽  
Industrial Process ◽  
Minor Component ◽  
Analytical Techniques ◽  
High Yield ◽  
Planning Time ◽  
Unit Operations ◽  
Key Points ◽  
A Minor ◽  
Scale Of Operation

Practical approaches to protein purification contains detailed practical information on separations techniques and the chapters of Protein purification techniques cover the unit operations and analytical techniques involved in some detail while Protein purification applications provides details of how to approach purification from a selected number of typical sources. However a key element of every purification, whether in University research or as part of scaling-up an industrial process, is planning. Time spent at the outset in establishing the key goals of the process prior to going into the laboratory will invariably save much time and effort. Key points to consider from the outset are: (a) Why are you doing the work—what is the reason for the purification? (b) What are the key considerations in selecting how to purify? (c) What implications does this have on how you will approach the purification? At the start of a purification, the target protein may be a minor component among millions of other proteins and other contaminants. This presents boundless opportunities for miscalculations, blind-alleys, and wasted effort. Years of practical work by separation scientists have derived certain rules which will help to minimize such problems and ensure protein purifications are successful. Here are ten purification rules to consider: 1. Keep the purification simple—minimize the number of steps and avoid difficult manipulations which will not reproduce. 2. Keep it cheap—avoid expensive techniques where a cheaper one will do. 3. Adopt a step approach—and optimize each step as you go. 4. Speed is important—avoid delays and slow equipment. 5. Use reliable techniques and apparatus. 6. Spend money on simple bits and pieces—e.g. test-tubes, pipettes. 7. Write out your methods before you start and record what you have done accurately. 8. Ensure your assays are developed to monitor the purification. 9. Keep notes on yields and activity throughout. 10. Bear in mind your objectives—be it high yield, high purity, final scale of operation, reproducibility, economical use of reagents/apparatus, convenience, throughput. Protein purification uses time, money, effort, and valuable equipment. Therefore, it is always advisable to pause for some moments to consider the reasons for purification in the first place.

scholarly journals Zur Reaktion von (CO)4FeP(R)Cl2 mit Na2Cr2(CO)10 / Reactions of (CO)4FeP(R)Cl2 with Na2Cr2(CO)10

1986 ◽  
Vol 41 (5) ◽  
pp. 532-540 ◽  
Author(s):  
Jutta Borm ◽  
Konrad Knoll ◽  
Laszlo Zsolnai ◽  
Gottfried Huttner
Keyword(s):  
Spectroscopic Data ◽  
Minor Component ◽  
Major Product ◽  
High Yield ◽  
Analogous Reaction ◽  
X Ray ◽  
A Minor

(CO)4FeP(R)Cl2 reacts with Na2Cr2(CO)10 to give the μ3 RP capped trigonal heterom etallic closed cluster Fe(CO)3Cr(CO)4Cr(CO)5(μ3-PR)(1) as a major product. ACr(CO)5-derivative of a metal substituted phosphane [(μ2(tBuPCl)Fe2(CO)7)(tBuPH)]Cr(CO)5 (2) is obtained as a minor component.The analogous reaction with (CO)4FeP(Ph)Cl2 only gives the known cluster Fe3(CO)9(μ3-PR)2 (3), while (CO)4FeP(c-hexyl)Cl2 results in 4, a pentacarbonylchromiumderivative of the diiron species Fe2(CO)6μ-(PR)3. Species o f this type, containing an Fe2(CO)6 entity doubly bridged by μ2-PR entities, which are them selves linked by another PR-group, are obtained in a systematic high yield process by reacting Fe2(CO)6(μ2-RPH)2 with n-BuLi/TMEDA , RPCl2. For com pound identification, analytical and spectroscopic data as well as four X-ray analyses are presented.

Protonation effects on dynamic flux properties of aqueous metal complexes

2009 ◽  
Vol 74 (10) ◽  
pp. 1543-1557 ◽  
Author(s):  
Herman P. Van Leeuwen ◽  
Raewyn M. Town
Keyword(s):  
Complex Formation ◽  
Metal Ion ◽  
Good Description ◽  
Minor Component ◽  
Outer Sphere ◽  
Metal Species ◽  
Central Metal ◽  
Inner Sphere ◽  
A Minor ◽  
Protonated Ligand

The degree of (de)protonation of aqueous metal species has significant consequences for the kinetics of complex formation/dissociation. All protonated forms of both the ligand and the hydrated central metal ion contribute to the rate of complex formation to an extent weighted by the pertaining outer-sphere stabilities. Likewise, the lifetime of the uncomplexed metal is determined by all the various protonated ligand species. Therefore, the interfacial reaction layer thickness, μ, and the ensuing kinetic flux, Jkin, are more involved than in the conventional case. All inner-sphere complexes contribute to the overall rate of dissociation, as weighted by their respective rate constants for dissociation, kd. The presence of inner-sphere deprotonated H2O, or of outer-sphere protonated ligand, generally has a great impact on kd of the inner-sphere complex. Consequently, the overall flux can be dominated by a species that is a minor component of the bulk speciation. The concepts are shown to provide a good description of experimental stripping chronopotentiometric data for several protonated metal–ligand systems.

scholarly journals Multistep batch-flow hybrid synthesis of a terbinafine precursor

2021 ◽  
Author(s):  
Tamás Hergert ◽  
Béla Mátravölgyi ◽  
Róbert Örkényi ◽  
János Éles ◽  
Ferenc Faigl
Keyword(s):  
Methyl Ether ◽  
Lithium Salt ◽  
Scale Up ◽  
Hybrid Process ◽  
High Yield ◽  
Grignard Reaction ◽  
Efficient Synthesis ◽  
Synthetic Process ◽  
Synthesis Route ◽  
Selective Addition

AbstractA three-step batch-flow hybrid process has been developed for an expeditious synthesis of the enynol key intermediate of antifungal terbinafine. This procedure involves consecutive organometallic steps without the necessity of any in-line purification: after a metalation by n-butyllithium, a selective addition of the lithium salt was elaborated followed by a Grignard reaction resulting in a high yield of 6,6-dimethylhept-1-en-4-yn-3-ol. Moreover, as an alternative to tetrahydrofuran, cyclopentyl methyl ether was used as solvent implementing a safe, sustainable, yet selective synthetic process. Even on a laboratory-scale, the optimized batch-flow hybrid process had a theoretical throughput of 41 g/h. Furthermore, the newly developed process provides an efficient synthesis route to the key-intermediate, while making acrolein obsolete, minimizing side-products, and enabling safe and convenient scale-up.

Petrography and provenance of the Marambio Group, Vega Island, Antarctica

1994 ◽  
Vol 6 (4) ◽  
pp. 517-527 ◽  
Author(s):  
Duncan Pirrie
Keyword(s):  
Late Cretaceous ◽  
Sedimentary Rocks ◽  
Clay Mineralogy ◽  
Minor Component ◽  
Source Area ◽  
Low Grade ◽  
Western Margin ◽  
Sediment Input ◽  
A Minor ◽  
Sandstone Petrography

Late Cretaceous sedimentary rocks assigned to the Santa Marta (Herbert Sound Member) and López de Bertodano (Cape Lamb and Sandwich Bluff members) formations of the Marambio Group, crop out on Cape Lamb, Vega Island. Although previous studies have recognized that these sedimentary rocks were derived from the northern Antarctic Peninsula region, the work presented here allows the provenance and palaeogeographical evolution of the region to be described in detail. On the basis of both sandstone petrography and clay mineralogy, the Herbert Sound and Cape Lamb members reflect sediment input from a low relief source area, with sand grade sediment sourced from low grade metasediments, and clay grade sediment ultimately derived from the weathering of an andesitic source area. In contrast, the Sandwich Bluff Member reflects a switch to a predominantly andesitic volcaniclastic source. However, this sediment was largely derived from older volcanic suites due to renewed source area uplift, with only a minor component from coeval volcanism. Regional uplift of both the arc terrane and the western margin of the James Ross Basin was likely during the Maastrichtian.

scholarly journals Species pattern of phosphatidylinositol from lung surfactant and a comparison of the species pattern of phosphatidylinositol and phosphatidylglycerol synthesized de novo in lung microsomal fractions

1988 ◽  
Vol 254 (1) ◽  
pp. 67-71 ◽  
Author(s):  
B Rüstow ◽  
Y Nakagawa ◽  
H Rabe ◽  
K Waku ◽  
D Kunze
Keyword(s):  
Lung Function ◽  
Molecular Species ◽  
De Novo ◽  
Lung Surfactant ◽  
Minor Component ◽  
Main Species ◽  
Surfactant Phospholipids ◽  
Species Pattern ◽  
A Minor

1. Phosphatidylinositol (PI) is a minor component of lung surfactant which may be able to replace the functionally important phosphatidylglycerol (PG) [Beppu, Clements & Goerke (1983) J. Appl. Physiol. 55, 496-502] without disturbing lung function. The dipalmitoyl species is one of the main species for both PI (14.4%) and PG (16.9%). Besides the C16:0--C16:0 species, the C16:0--C18:0, C16:0--C18:1, C16:0--C18:2 and C18:0--C18:1 species showed comparable proportions in the PG and PI fractions. These similarities of the species patterns and the acidic character of both phospholipids could explain why surfactant PG may be replaced by PI. 2. PI and PG were radiolabelled by incubation of microsomal fractions with [14C]glycerol 3-phosphate (Gro3P). For 11 out of 14 molecular species of PI and PG we measured comparable proportions of radioactivity. The radioactivity of these 11 species accounted together for more than 80% of the total. The addition of inositol to the incubation system decreased the incorporation in vitro of Gro3P into PG and CDP-DG (diacylglycerol) of lung microsomes (microsomal fractions), but did not change the distribution of radioactivity among the molecular species of PG. These results supported the idea that both acidic surfactant phospholipids may be synthesized de novo from a common CDP-DG pool in lung microsomes.

scholarly journals Recreational Harvest of Sharks and Rays in Western Australia Is Only a Minor Component of the Total Harvest

2021 ◽  
Vol 13 (11) ◽  
pp. 6215
Author(s):  
Matias Braccini ◽  
Eva Lai ◽  
Karina Ryan ◽  
Stephen Taylor
Keyword(s):  
Western Australia ◽  
Minor Component ◽  
The North ◽  
Commercial Harvest ◽  
Unknown Status ◽  
Reef Sharks ◽  
Conservation Concern ◽  
Taxonomic Groups ◽  
A Minor ◽  
Port Jackson

Sharks and rays are a global conservation concern with an increasing number of species considered at risk of extinction, mostly due to overfishing. Although the recreational harvest of sharks and rays is poorly documented and generally minimal, it can be comparable to the commercial harvest. In this study, we quantified the recreational harvest of sharks and rays in Western Australia, a region with a marine coastline greater than 20,000 km. A total of 33 species/taxonomic groups were identified, with the harvest dominated by dusky and bronze whalers, blacktip reef sharks, gummy sharks, Port Jackson sharks, wobbegongs, and rays and skates. Eighty-five percent of individuals were released with an unknown status (alive or dead). We found a latitudinal gradient of species composition, with tropical and subtropical species of the genus Carcharhinus dominating in the north and temperate species from a range of families dominating in the south. Overall, our findings showed that the recreational harvest was negligible when compared with commercial landings.

Enantioselective synthesis of (R)-tolterodine using lithiation/borylation–protodeboronation methodology

2012 ◽  
Vol 90 (11) ◽  
pp. 965-974 ◽  
Author(s):  
Stefan Roesner ◽  
Varinder K. Aggarwal
Keyword(s):  
Enantioselective Synthesis ◽  
High Yield ◽  
Magnesium Bromide ◽  
Efficient Synthesis ◽  
Boronic Ester ◽  
Better Than

The synthesis of the pharmaceutical (R)-tolterodine is reported using lithiation/borylation–protodeboronation of a homoallyl carbamate as the key step. This step was tested with two permutations: an electron-neutral aryl Li-carbamate reacting with an electron-rich boronic ester and an electron-rich aryl Li-carbamate reacting with an electron-neutral boronic ester. It was found that the latter arrangement was considerably better than the former. Further improvements were achieved using magnesium bromide in methanol leading to a process that gave high yield and high enantioselectivity in the lithiation/borylation reaction. The key step was used in an efficient synthesis of (R)-tolterodine in a total of eight steps in a 30% overall yield and 90% ee.

Sign in / Sign up

Export Citation Format

Share Document