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Enzymatic Synthesis of 7-Deoxy-N-acetylneuraminic Acid and 7-O-Methyl-N-acetylneuraminic Acid


09 Dec 2016

Modifications implemented to improve yields

I used the published synthethic methods for both deoxy and methoxy derivatives with some modifications and obtained a lot higher yields.

Deoxy: 2 eq of 1,1′-Thiocarbonyldiimidazole is enough (paper is 2.5 eq) and I used 1,2-dichloroethane instead of CH2Cl2...

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Efficient, one-pot syntheses of biologically active α-linked glycolipids


09 Dec 2016

Adjustments needed to increase efficiency of methodology

The methodology described in this article is very valuable for scientists working with glycosphingolipids. It provided a one-pot syntheses of alpha-linked glycolipids with the possibility of using substrates with unsaturations in the fatty acid side...

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Total Synthesis and Biological Evaluation of Glycolipids Plakosides A, B and Their Analogs


09 Dec 2016

Easy to follow procedures; yields not reproducible

In one of my Ph.D. projects where I was working on the total syntheses of glycosphingolipids, I followed this reference to prepare some of the intermediates. This is a very important publication in the glycolipid field since it is among the few papers that...

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Benzobisthiazole-Based Donor–Acceptor Copolymer Semiconductors for Photovoltaic Cells and Highly Stable Field-Effect Transistors


09 Dec 2016

Good synthesis; product easy to isolate

Synthesized 2,6-Bis(3-dodecylthiophen-2-yl)benzobisthiazole following the procedure.

(1) The reaction was reproduced with higher yields (>25%).

(2) Added the 2-carboxylaldehydethiophene derviative by portions, used longer reaction time (24hs) and...

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CHLOROSULFONATION OF SOME POLYNUCLEAR HETEROCYCLIC COMPOUNDS


09 Dec 2016

Lacking complete isolation/purification procedures

This article reported the synthesis of different sulfonyl chloride of polynuclear heterocyclic compounds which are very important intermediates to form different derivatives like sulfonates. Unfortunately, this paper is lacking a complete isolation and...

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Butane 2,3-Bisacetal Protection of Vicinal Diequatorial Diols


09 Dec 2016

Clear, Detailed Paper

After searching for an alternate protecting group for the protection of cis-dihydrocatechols, it was found that the butane-bisacetals were more resilient to hydrolysis. This is crucial when protecting group stabiity is required for acetals that are exposed to...

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A Practical Synthesis of C2-Symmetric Chiral Binaphthyl Ketone Catalyst


09 Dec 2016

Several Recommendations for Improved Synthesis

Summary:

A practical synthesis of 11-membered C2-symmetric binaphthyl ketone (R)-1, a catalyst for asymmetric epoxidation, was developed. This manuscript describes the single example of chiral resolution of (±)-1,1’-Binaphthyl-2,2’-dicarboxylic acid [(±)-6...

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Practical Synthesis of Unsymmetrical Ureas from Isopropenyl Carbamates


09 Dec 2016

Mild, High Yielding Method

Ureas are very widely used synthetic targets in pharmaceutical industry especially as kinase inhibitors. Using this methodology we have synthesized thousands of unsymmetrical ureas as kinase inhibitors. This method is a very mild, high yielding and can work...

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Hydroboration. 97. Synthesis of New Exceptional Chloroborane−Lewis Base Adducts for Hydroboration. Dioxane−Monochloroborane as a Superior Reagent for the Selective Hydroboration of Terminal Alkenes†


09 Dec 2016

Equivalency of reagents key for successful synthesis

Review: Synthesized the same compound of Dioxane-Monochloroborane by the reaction of Sodium Borohydride with Dioxane-borontrichloride (experimental section, Page 5364). I found the equivalency of the reagents is very important for this reaction. The reaction...

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Construction of the Bicyclo[3.1.0]hexane Template of a Conformationally Locked Carbocyclic Adenosine via an Olefin Keto-Carbene Cycloaddition


09 Dec 2016

Experimental Yields Lower than Literature

Victor E. Marquez et. al. first introduced the concept of locked conformations, 2'-exo (North) and 3'-exo (South), of ribose ring in nucleosides. In this article the synthetic methodology and successful synthesis of receamic and conformationally locked South...

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Enantiomers of 1-ethyl-7-[3-[(ethylamino)methyl]-1-pyrrolidinyl]-6,8-difluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid: preparation and biological activity


09 Dec 2016

Procedure Adapted for Better Synthesis

Wanting to avoid a chromatographic separation of the Me esters as well as the greater expense of dimethyl itaconate, the reaction of alpha methyl benzylamine and itaconic acid was performed in xylene.  The reaction was performed by adding the amine at 110 to...

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Catalytic Isomerization of Cyanoolefins Involved in the Adiponitrile Process. C−CN Bond Cleavage and Structure of the Nickel π-Allyl Cyanide Complex Ni(η3-1-Me-C3H4)(CN)(dppb)


09 Dec 2016

Helpful experimental; Some discrepancies observed in NMR

The article reports the catalytic isomerization of the branched cyanoolefin 2-methyl-3-butenenitrile (2M3BN) to the linear isomer 3-pentenenitrile (3PN) using nickel-phosphine complexes.

The authors report that the optimal catalytic experiment was carried...

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Isolation and reactions of .alpha.-lithio N,N-dimethylacetamide


09 Dec 2016

Reproducible Experimental

Summary: The paper discusses the synthesis, reactivity and stability of α-lithio N,N dimethylacetamide.

The paper described carefully the use of various solvents (pentane, THF) and their impact on the formation of the desired product.

It also described...

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A Convenient Synthesis of Novel Bifunctional Prochelators for Coupling to Bioactive Peptides for Radiometal Labelling


09 Dec 2016

Extremely helpful and reliable paper

 

Summary

The article describes the synthesis of cyclen based chelators which can accommodate and stabilize di-and trivalent metal ions for biomedical applications. The chelators were synthesized first by monoalkylating cyclen (1,4,7,10...

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DIPHENALDEHYDE


09 Dec 2016

Reliable Procedure

The procedure described in this paper is very reliable. The ozone should be used in a fully functional fume hood as described.

1. Synthesized 10.1 g of crude diphenaldehyde starting from 10.0 g of phenanthrene.

2. The crude 1H-NMR of product is 80%...

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Selective Bromination of Perylene Diimides under Mild Conditions


09 Dec 2016

Good experimental, some modification to work-up

In this paper, selective bromination of perylene diimides is described. I was able to reproduce the bromination of 1a. However, the workup involves evaporating large volumes of bromine. I was able to isolate similar yields of products by quenching the...

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Enantioselective formation of functionalized 1,3-disubstituted allenes: synthesis of .alpha.-allenic .omega.-carbomethoxy alcohols of high optical purity


09 Dec 2016

Few Experimental Modifications Implemented to Improve Yield

Synthesized (3) and a compound similar to (4) but with protection on -OH groups. 

For (3): Dissolving CBr4 in dichloromethane instead of pyridine gave a better yield as it involved using only one solvent throughout the reaction. 

For (4): The formation...

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Synthesis and reactions of the cyclic silyl peroxide 1,1,4,4-tetramethyl-2,3-dioxa-1,4-disilacyclohexane


09 Dec 2016

Exact Procedure Not Provided By Authors

Summary:

The first simple cyclic silyl peroxide, namely 1,1,4,4,-tetramethyl-1,4-disila-2,3-dioxane, was prepared by classical synthetic methodology from its corresponding cyclic disilazane and the urea complex of hydrogen peroxide.

The Reaction of...

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Total Synthesis of the Hsp90 Inhibitor Geldanamycin


09 Dec 2016

Amazingly short synthesis for complex macrolide

This paper describes amazingly shortest synthesis for such a complex macrolide. Geldanamycin was synthesized in 20 steps using key steps such as Cu-catalyzed intramolecular amidation. I have used synthetic strategy to synthesize prodrug of geldanamycin with...

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On a new synthesis of sterpurene and the bioactivity of some related Chondrostereum purpureum sesquiterpene metabolites


09 Dec 2016

Reliable procedure but modifications helpful

The article by Strunz and co-workers reported a total synthesis of sterpurene and the bioactivity of some related sesquiterpene metabolites.

I am particularly interested in the preparation of intermediate 14 (4-step synthesis, Scheme 3) since it could...

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