Vidya Bhushan’s research while affiliated with RWTH Aachen University and other places

... Unfortunately, attempts to form the aryl-aryl bond, using Stille-Kelly cross-coupling conditions (Pd(PPh 3 ) 4 , Sn 2 Bu 6 , 140°C), only gave trace amounts of biaryl 53 (Scheme 6B). [26,47,48] We then set out to reduce electron richness of the system and synthesized ester 56 (see the Supporting Information for details) from phenol 54 and acyl chloride 55. Surprisingly, when subjecting 56 to the same conditions, only decomposition was observed, presumably due to instability of the aldehyde moiety (Scheme 6C). PCy 3 •HBF 4 and potassium carbonate at elevated temperatures (130°C) in DMA [49] led to a regioisomeric mixture of biaryl 62 and 61 in 3:1 ratio favoring the undesired sterically less hindered regioisomer (Scheme 6D). ...

Reference:

Evolution of a Strategy for the Total Synthesis of the Ganoderma Meroterpenoid Ganoapplanin

... Known, synthetically useful, C-heteroatom bond forming reactions of R-metalated hydrazones 25 (Scheme 24) include R-sulfenylation with disulfides 154 or benzenesulfe-nyl chloride (product 146), selenylation with benzeneselenenyl bromide (product 147), 155 R-phosphinylation 156 with borane-protected chloro-disubstituted phosphane (product 149), R-amination with TrisN 3 , 157 di-tert-butyl azodicarboxylate (DBAD), 157 or (diphenylphosphinyl)(N,N-dimethylamino)hydroxylamine (product 150), R-hydroxylation with oxaziridines (product 151), 158 and R-silylation with silyl triflates or chlorosilanes to form 148. 159 R′-Silyl enol ethers of R-silyl ketones obtained from 148 are useful reagents for regio-and enantioselective Mannich reactions (electrophile Bn 2 NCH 2 OCH 3 with BF 3 · Et 2 O). 160 In recent years, hydrazones have been used, among other things, for the introduction of heteroatoms in the R-position of ketones and aldehydes. ...

Reference:

N,N-Dialkylhydrazones in Organic Synthesis. From Simple N,N-Dimethylhydrazones to Supported Chiral Auxiliaries

... They were most often obtained in a reaction of dicarboxylic acid chlorides and the alkaloids. Usually the transformation was carried in the presence of a base such as triethylamine [71] and sometimes with catalytic amounts of 4dimethylaminopyridine (DMAP). The yields, when reported, were above 70 %. ...

Reference:

Dimeric Cinchona Alkaloids

... In light of the importance of enantioenriched allylsilanes, the construction of this class of chiral compounds has attracted much attention. [7] Traditional synthetic routes for the preparation of enantioenriched allylsilanes normally starts from the optically active substrates via stoichiometric reactions, including Wittig olefination with optically active α-silylaldehydes, [8] allylic rearrangement (S N 2' reaction) [9] and Claisen rearrangement. [10] In addition, catalytic methods with the chiral auxiliary, [11] chiral substrate, [12] or chiral silicon reagent [13] are also demonstrated in the literature. ...

Reference:

Catalytic Enantioselective Preparation of Chiral Allylsilanes

... These compounds play important roles in the synthesis of products which possess heteroatomic functional groups and, again, the reason for their increasing use nowadays is the emergence of several new effective methods for their synthesis [4]. In spite of their recent exploitation in organic synthesis, the synthesis and reactivity of both cyclic sulfites and sulfates [3] [5] [6] [7] as well as cyclic sulfamidates [4] [6] have been already reviewed and the readers are referred to these sources of information for a deeper outlook. ...

Reference:

Synthetic Applications of Cyclic Sulfites, Sulfates and Sulfamidates in Carbohydrate Chemistry

... Recent studies on molecular modification of the later 1H, 3H-thiazolo [3,4-a] benzimidazoles (TBZs) revealed that, dismantling of the imidazole nucleus leading to the design of new 4-oxo-thiazolidine derivatives, maintained the molecular requirements for enzyme inhibition. A literature search revealed that 4-oxo-thiazolidine derivatives may exhibit anti-HIV (Rawal et al., 2005) enzyme murB (Andres et al., 2000), antimicrobial activity , antituberclousis (Babaoglu et al., 2003;Govindarajan et al., 2003) antiproliferative agent (Ottana`et al., 2005), CNS activity (Basu et al., 2008), cytotoxic agent (Gududuru et al., 2005), anticonvulsant activity (Archana et al., 2002), antibacterial activity (Bonde and Gaikwad, 2004;Sayyed et al., 2006), analgesic agent (Moustfa et al., 1989), antiinflammetry agent (Vigorita et al., 2001;Goel et al., 1999), antihypertensive agent (El-subbagh, 1999), and hypolipidemic agent (Lohary et al., 1999) properties. ...

Reference:

Synthesis, characterization and biological evaluation of 4-oxo-thiazolidine compounds

... Cyclic sulfates [13] are diesters of sulfuric acid, commonly used in organic chemistry for mono functionalization of vicinal diols. They are better leaving groups than the more commonly used leaving groups tosylates and mesylates, and are fairly stable compounds [14]. We speculated that, if we could prepare an asymmetrical cyclic sulfate involving a phenol and an aliphatic alcohol, a nucleophilic reagent would react with the aliphatic side of the cyclic sulfate and generate a phenolic sulfate ester on the other side. ...

Reference:

Radioiodination of Aryl-Alkyl Cyclic Sulfates

... The AH reaction has been studied extensively by Sharpless et al. [4,5], and more recently, considerable interest has focused on the AH reaction, as β-amino alcohols are an important functionality in chiral ligands and biologically active compounds [6]. β-Amino alcohols are classified into three general groups, including (i) naturally occurring compounds, (ii) synthetic pharmacologically active molecules, and (iii) chiral ligands [7][8][9]. ...

Reference:

The Heterogeneous Aminohydroxylation Reaction Using Hydrotalcite-Like Catalysts Containing Osmium

... In particular, D2PM and its analogs are organocatalysts used for various asymmetric syntheses; however, such chemical reagents are likely abused. [3][4][5][6][7] To prevent distribution of these substances, it is crucial to establish an analytical method of detection before they enter the Japanese market. Therefore, development of simple and rapid screening methods of illicit drugs and their structurally related compounds is required. ...

Reference:

Rapid enantiomeric separation and simultaneous determination of phenethylamines by ultra high performance liquid chromatography with fluorescence and mass spectrometric detection: Application to the analysis of illicit drugs distributed in the Japanese market and biological samples

... Also, it exhibited a superior antihyperlipidemic effect compared to Troglitazone and Rosiglitazone drugs via improving the HDL cholesterol levels. 68 The imidazopyridyl derivative (23) also revealed promising outcomes as a hypoglycemic agent but with lesser adverse effects often associated with Rosiglitazone, like cardiovascular diseases. 69 Indole and imidazopyridyl rings have behaved as the best lipophilic moieties to represent the lipophilic tail fraction to minimize the side effects besides improving the agonist activity for PPAR-γ. ...

Reference:

Peroxisome proliferator-activated receptors as superior targets to treat diabetic disease, design strategies - review article