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Questions related from Dhirendra Kumar
When HOCl is added to propene, the product is 1-chloro 2-propanol. However, when the same HOCl adds to allyl alcohol, the expected product is 3-chloropropan-1, 2-diol. But actually,...
10 October 2019 8,320 4 View
Usually CCl4 is considered as best solvent for Wohl-Ziegler Reaction or other free radical reactions (bromomethylation etc). However, several labs/institutes restricted its widespread use due to...
03 March 2017 7,040 3 View
The preparation of 2,7-bis(1,1-dimethylethyl)-pyrene is carried out using tert-butyl chloride in presence of AlCl3. Whether the same protocol can be used to prepare 2,7-dimethylpyrene...
05 May 2016 3,376 6 View
I did the halogen dance reaction of 2-bromo-5-TIPS thiophene using LDA/methanol to get 3-bromo-5-TIPS thiophene. But there reaction was not completed 100% and there is ~5-10% of starting material...
12 December 2015 178 2 View
There is no report of Rosenmund-von Braun Reaction of bromo-benzothiadiazoles. Is it possible or not? Moreover I am looking for selective mono-cyanation of dibromo-benzothiadiazole.
10 October 2015 3,814 6 View
Generally it was found that the use of additives in redox mediator [iodide/triiodide] cause not only improved performance but also increase device stability. In particular, I want to know the...
07 July 2015 4,911 4 View
The base promoted N-alkylation [SN2] using NaOH, KOH, NaH, K2CO3 etc of simple aromatic amines is well reported. Can the alkylation of amides be performed easily, then which method should be...
05 May 2015 9,503 8 View
For instance, 4,4,5,5-tetramethyl-2-(thiophen-3-yl)-1,3,2-dioxaborolane can be treated safely with BuLi; or the presence of -boronic ester would give trouble. Is any other reagent such as LDA can...
02 February 2015 545 3 View
The commonly used lithiating reagent, BuLi can be used for the thiophene-derivatives having primary amine; e.g. 4-(thiophen-2-yl)aniline. Alternatively which reagents can be used to get the...
01 January 2015 5,639 5 View
For instance, among N-chlorosuccinimide, N-bromosuccinimide and N-iodosuccinimide, which one would give most feasible respective halogenated product once reacted with an aromatic?
11 November 2014 4,344 5 View
In most of the reports, LDA has been used to convert 2-bromothiophenes to 3-bromothiophenes, smoothly. The similar strategy will work for the 2-chlorothiophenes or not?
11 November 2014 5,305 1 View
I have seen a paper (attached) and also observed myself that phenazine/dihydrophenazine-based compounds either didn't show or have very-2 broader peaks in the proton NMR when recorded in the...
10 October 2014 1,737 2 View
The milder method for the exclusive oxidation of the aromatic aldehyde having electron rich skeleton. I am worried about oxidation of aromatic part also under harsh conditions.
10 October 2014 2,066 21 View
The best C-C coupling of the bromo-aryl having -NO2 group, out of Kumada, Negishi, Stille or Suzuki. The main issue is whether the corresponding grignard reagent, Zn-reagent, Tin-reagent or...
08 August 2014 7,468 9 View
i) Bromo-substrate with electronic withdrawing group and boronic acid-substrate with electronic donating group OR ii) electron-rich bromo-substrate and electron-deficient boronic...
07 July 2014 3,620 6 View
Which one is more clean and efficient C-C coupling? Negishi or Stille?
07 July 2014 5,335 5 View
The synthesis of 2-Bromomethyl-5-bromothiophene can be easily carried out by treating 2-methylthiophene with NBS in CCl4 as I found in several papers. But in this article, in addition of aforesaid...
06 June 2014 1,084 9 View
The reaction of aryl phosphonates with carbonyls in the presence of t-BuOK in THF yields exclusively (E-)olefins. Can the use of LiCl further improve the (E)-isomer up to 100%?
06 June 2014 5,518 8 View
What will be the most efficient method for the following synthesis?
06 June 2014 5,863 3 View
The substrate is somewhat different than following (Indole) and the -NH derivative is highly air-sensitive; so I am worrying about hydrolysis followed by alkylation method.
04 April 2014 6,502 7 View
Two isomers of the aldehydes have the same polarity and could not be purified by column chromatography (by using any cosolvent system); re-crystallization was also not possible, as it is...
04 April 2014 6,331 6 View
Generally for the bromination of acetanilide, sodium bromate+HBr in AcOH method is preferred because of in-situ generation of bromine and thus handling of small to larger scale reactions. Can the...
04 April 2014 4,214 5 View
I did N-alkylation of a substrate by using K2CO3, 2-ethylhexyl bromide in DMF. After purification by column chromatography I got a liquid product. The problem is the presence of 2-ethylhexyl...
03 March 2014 417 10 View
There are number of methods for the synthesis of Pd(PPh3)2Cl2 from PdCl2. Which one is best among all in terms of yield and efficacy?
03 March 2014 6,300 8 View
