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.

Catalytic enantioselective synthesis of indolizino[8,7-b]indole alkaloid derivatives based on the tandem reaction of tertiary enamides

2021 ◽  
Author(s):  
Xin-Ming Xu ◽  
Ming Xie ◽  
Jiazhu Li ◽  
Mei-Xiang Wang
Keyword(s):  
Indole Alkaloid ◽  
Enantioselective Synthesis ◽  
High Yield ◽  
Tandem Reaction ◽  
Indole Derivatives

An exquisite Pybox/Cu(OTf)2-catalyzed asymmetric tandem reaction of tertiary enamides was developed, which enabled the expeditious synthesis of indolizino[8,7-b]indole derivatives in high yield, excellent enantioselectivity and diastereoselectivity.

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.

scholarly journals Glycosylation of Stannyl Ceramides Promoted by Modified Montmorillonite­ in Supercritical Carbon Dioxide

Synthesis ◽  
2017 ◽  
Vol 50 (03) ◽  
pp. 593-598
Author(s):  
José Morales-Serna ◽  
Bao Nguyen ◽  
Eréndira García-Ríos ◽  
Rubén Gaviño ◽  
Jorge Cárdenas ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
High Yield ◽  
Efficient Synthesis ◽  
Supercritical Carbon

The direct glycosylation of ceramides in supercritical carbon dioxide (scCO2) successfully proceeded to produce β-glycolipids in high yield and with full stereoselectivity. The reaction is promoted by montmorillonite modified with a superacid (CF3SO3H). The value of this protocol was demonstrated in the efficient synthesis of isoglobotrihexosylceramide (iGB3).

A short synthesis of both enantiomers of enterolactone

2000 ◽  
Vol 78 (1) ◽  
pp. 133-138 ◽  
Author(s):  
Mukund P Sibi ◽  
Pingrong Liu ◽  
Michael D Johnson
Keyword(s):  
Key Words ◽  
Enantioselective Synthesis ◽  
Efficient Synthesis ◽  
Short Synthesis

A short and efficient synthesis of both enantiomers of enterolactone, a mammalian lignan, is described. The overall yield for the natural enterolactone, over seven steps, was 19% and for its enantiomer 27%. Key words: enterolactone, 4-diphenylmethyl-2-oxazolidinone, succinate, enantioselective synthesis.

Bromination of Tetralin. Short and Efficient Synthesis of 1,4-Dibromonaphthalene

2000 ◽  
Vol 65 (11) ◽  
pp. 1791-1804 ◽  
Author(s):  
Osman Çakmak ◽  
Ismail Kahveci ◽  
Íbrahim Demirtaş ◽  
Tuncer Hökelek ◽  
Keith Smith
Keyword(s):  
High Temperature ◽  
Major Product ◽  
High Yield ◽  
Efficient Synthesis ◽  
Secondary Products ◽  
Derivatives Of ◽  
Sole Product

High-temperature bromination of tetralin (1,2,3,4-tetrahydronaphthalene) with bromine resulted in benzylic bromination to give 1,4-dibromo-1,2,3,4-tetrahydronaphthalene (4) as a major product and several secondary products. Photolytic bromination of tetralin and subsequent double dehydrobromination of 1,1,4,4-tetrabromo-1,2,3,4-tetrahydronaphthalene (10) gave 1,4-dibromonaphthalene (11) as the sole product in a high yield. 1,4-Dibromonaphthalene is efficiently converted to the corresponding methoxy (12 and 13) and cyano (14 and 15) derivatives of naphthalene.

A Review: Extraction of Platinum Spent Catalyst Using Palm Oil Leaf as Reducing Agent

2015 ◽  
Vol 1113 ◽  
pp. 317-321
Author(s):  
Mohd Rashwan Taufiq Khairol Anwar ◽  
Norashikin Ahmad Zamanhuri ◽  
Junaidah Jai ◽  
Noorsuhana Mohd Yusof
Keyword(s):  
Palm Oil ◽  
High Stability ◽  
High Selectivity ◽  
Reducing Agent ◽  
High Yield ◽  
Spent Catalyst ◽  
Recovery Method ◽  
Paper Review ◽  
Better Than

Platinum is commercially used in the catalytic industry for ages. The use of platinum has been significantly practiced because of its enhancing properties. There are a few advantages of using platinum such as high selectivity, high yield, high stability and able to undergo improvisation. However, when platinum lifetime is out, it is treated mainly as waste. Low recovery of platinum spent catalyst brought to the existence of recovery method using acidic and alkaline method. Proved to be harmful, green subtances were used as substitute for the chemical in recovering platinum. Therefore, a cheaper, safer and more environmentally method of recovery. Thus,this paper review about recovering platinum using palm oil leaf and how it is better than the existed chemical based method.

Impact of the Variable Sampling Intervals Scheme on the CQC Chart

2013 ◽  
Vol 456 ◽  
pp. 627-630
Author(s):  
Ying Zhang ◽  
Xiao Juan Wang
Keyword(s):  
Sampling Interval ◽  
High Yield ◽  
Average Time To Signal ◽  
Inspection Cost ◽  
Variable Sampling Interval ◽  
Variable Sampling ◽  
Sampling Intervals ◽  
Quantity Control ◽  
Better Than

The Cumulative Quantity Control (CQC) chart which is based on monitoring the cumulative quantity of product manufactured has been shown to be useful for monitoring high yield processes. However, this chart is not so sensitive to small process changes and the inspection cost could be high if the inspection is frequent. In this paper, a variable sampling interval procedure of the CQC chart is developed and studied. We compare the performance of the variable sampling interval CQC chart in terms of its average time to signal with the traditional CQC chart and prove that this new chart performs better than the traditional CQC chart. The use of variable sampling interval scheme could further enhance the efficiency of traditional CQC chart.

scholarly journals Efficient Asymmetric Synthesis of Prostaglandin E1

2007 ◽  
Vol 62 (4) ◽  
pp. 556-560 ◽  
Author(s):  
Jae-Chul Jung ◽  
Oee-Sook Park
Keyword(s):  
Asymmetric Synthesis ◽  
Michael Addition ◽  
Prostaglandin E1 ◽  
Simple Synthesis ◽  
High Yield ◽  
Prostaglandin E ◽  
Magnesium Bromide ◽  
One Pot ◽  
Asymmetric Michael Addition ◽  
Key Steps

A simple synthesis of prostaglandin E1 (PGE1) is described. The key steps are an asymmetric Michael addition to establish the desired (R)-configurations at C8 and C12 of the 2- (trimethylsilyl)ethoxymethyl- (SEM) protected PGE1 and its one-pot deprotection with magnesium bromide in high yield. This method is potentially useful for the preparation of other modified prostaglandins.

scholarly journals Solid Acid Hydrolysis for Isolation of Cellulose Nanocrystals and Chitin Nanocrystals – A mini review

2021 ◽  
Vol 11 (02) ◽  
pp. 69
Author(s):  
Frederikus Tunjung Seta ◽  
Xingye An ◽  
Hongbin Liu
Keyword(s):  
Acid Hydrolysis ◽  
Surface Charge Density ◽  
Recent Progress ◽  
Solid Acid ◽  
High Yield ◽  
Liquid Acid ◽  
Yield Production ◽  
High Yield Production ◽  
Bare Surface ◽  
Better Than

Cellulose and chitin are two of the most abundant biopolymer on earth, have been attracted a lot of interest from many researchers, especially related to their nanoparticles form. Recently the method to extract them into nanoscale materials mostly by mineral or liquid acid hydrolysis, such as sulfuric and hydrochloric acid. Despite their high yield production, many disadvantages are produced by their use as a hydrolysis catalyst, such as low thermal stability and are difficult to be functionalized due to the presence of sulfate groups, tendency to be aggregated due to the bare surface charge density, the potential excessive degradation of cellulose; and large amounts of effluent will be produced due to the neutralization stage and corrosion hazards to the equipment and environment. To overcome the drawback of those acids, solid acid can be used to produce cellulose (CNC) and chitin nanocrystals (ChNC). Their ability to recrystallize and recycle makes them more environmentally friendly, furthermore, most of the acid can do esterification on the surface of cellulose and chitin. The purpose of this paper is to provide a critical review of recent progress related to solid acid hydrolysis since they have interesting characterization even some of their attribute is better than the conventional method.

Sign in / Sign up

Export Citation Format

Share Document