Ethanol is shown to act as a hydrogenating agent for ynamides under palladium catalysis. This behavior is different from the normally expected reaction of ethanol addition to alkynes. The reaction ...shows stereoselectivity for E enamides, which is in contrast to reports using other hydrogenating sources. The method was also extended to ynamines. Alternatively, the use of ethanol and ammonium formate as the hydrogenating source gives Z enamides. The role of ethanol in hydrogenation was demonstrated by means deuterium labeling experiment.
One for the road: Ethanol acts as a hydrogenating agent for ynamides under palladium catalysis. This behavior is different from the normally expected addition of ethanol to alkynes. The reactions show stereoselectivity for E enamides, which is in contrast to reports using other hydrogenating sources, and the method was also extended to ynamines. Alternatively, the use of ethanol/ammonium formate as the hydrogenating source gives Z enamides.
Ru(
ii
)-catalysed oxidative (4 + 2) annulation of chromene and coumarin-3-carboxylic acids with alkynes/propargylic alcohols
via
sp
2
C-H bond activation is reported. While the reaction with alkynes ...affords highly substituted pyrano-chromones in good to excellent yields, the use of methyl-tethered propargylic alcohols in place of alkynes leads to novel Ru(0)-metal complexes in moderate to good yields; these complexes were stable in MeCO
2
H/O
2
. The generality of the reaction with alkynes is illustrated in the case of both symmetrical and unsymmetrical internal alkynes with excellent regioselectivity in the case of unsymmetrical alkynes.
Ru(
ii
)-catalysed oxidative (4 + 2) annulation of chromene and coumarin carboxylic acids with alkynes affords pyrano-chromones
via
vinylic C-H bond activation; use of methyl-tethered propargylic alcohols instead of alkynes gives Ru(0) complexes.
Lewis base dependent (3 + 3) annulation of δ-acetoxy allenoates with benzofuranone, pyrazolone, and Boc-protected oxindole is reported. In the presence of catalytic DBU, oxindole, benzofuranone, and ...pyrazolone undergo (3 + 3) annulation with δ-acetoxy allenoates
via
6-
exo-dig
cyclisation at room temperature (25 °C) to afford fused pyran scaffolds. On the other hand, by employing catalytic DMAP, the reaction between
N
-Boc-oxindole and δ-acetoxy allenoates goes through 6-
endo-dig
cyclisation, leading to distinct dihydropyrans that contain an exocyclic double bond; similar products were also obtained by using benzofuranone and pyrazolone.
Lewis base-controlled (3 + 3) annulation of δ-acetoxy allenoates with
N
-Boc-oxindole, benzofuranone, or pyrazolone affords fused pyrans; the base DBU gives pyrans, while DMAP affords dihydropyrans.
The reactivity of 2-sulfonamidoindoles with acetoxy allenoates under phosphine catalysis depends on the disposition of the acetoxy (OAc) group on the allenoate. In the temperature-controlled 3 + 3 ...annulations, δ-acetoxy allenoates afforded dihydrocarboline and carboline scaffolds with carbon–nitrogen nucleophilic 2-sulfonamidoindoles, in which allenoate serves as a β-, γ-, and δ-carbon donor. At room temperature (25 °C), dihydro-α-carboline motifs were obtained exclusively through Michael addition, 1,4-proton shift, isomerization, 1,2-proton transfer, phosphine elimination, and aza-Michael addition. The higher temperature (80 °C) cascade protocol using Ph3P–Cs2CO3 combination involves addition–elimination, aza-Claisen rearrangement, tosyl migration, and aromatization as key steps to give α-carbolines containing tosyl functionality at the γ-carbon. In contrast, with β′-acetoxy allenoate, 2-sulfonamidoindole acts only as a carbo-nucleophile in (p-tolyl)3P-directed 4 + 1 spiro-annulation, leading to five-membered spiro-carbocyclic motifs essentially as single diastereomers (dr >20:1) via chemoselective carbo-annulation.
The functionalization of materials for ultrasensitive detection of heavy metal ions (HMIs) in the environment is crucial. Herewith, we have functionalized inexpensive and environmentally friendly ...Fe3O4 nanoparticles with D-valine (Fe3O4–D–Val) by a simple co-precipitation synthetic approach characterized by XRD, FE-SEM, and FTIR spectroscopy. The Fe3O4–D–Val sensor was used for the ultrasensitive detection of Cd+2, Pb+2, and Cu+2 in water samples. This sensor shows a very low detection limit of 11.29, 4.59, and 20.07 nM for Cd+2, Pb+2, and Cu+2, respectively. The detection limits are much lower than the values suggested by the world health Organization. The real water samples were also analyzed using the developed sensor.
•MCDM methods: AHP and TOPSIS.•AHP the decision-maker.•TOPSIS is stock to an ideal solution.
Building an ideal stock portfolio is a difficult and important undertaking in the world of financial ...decision-making. The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) technique and the Randomised Weighted Fuzzy Analytic Hierarchy Process (AHP) are combined in this research to create a powerful model for selecting the best stocks for a portfolio. To improve the portfolio's robustness under various market scenarios, our model also incorporates sensitivity analysis. Given the inherent uncertainty in financial markets, the suggested approach starts by using modified fuzzy AHP based on introducing the randomized weights and the novel normalization to get expert views and assign suitable weights to the underlying selection criteria. Based on the established criteria and associated fuzzy scores, the TOPSIS approach is then used to rank and choose the best stocks. Our model also includes sensitivity analysis to evaluate the performance of the portfolio under various market conditions. Extensive empirical tests are performed utilizing historical stock market data to assess the effectiveness of our strategy. The outcomes show the suggested model's superiority in building stock portfolios that beat conventional approaches in terms of risk-adjusted returns.
The radionuclide transfer between compartments is commonly described by transfer parameters representing the ratio of concentrations of an element in two compartments for equilibrium conditions. This ...is a comprehensive study on the soil-to-grass transfer factor (F
) and grass-to-cow milk transfer coefficient (F
) for stable strontium (Sr) for soil-grass (pasture)-cow (Bos taurus) milk environmental pathway under field conditions for a high rainfall tropical monsoonal climatic region of the Indian subcontinent. The study was conducted in the vicinity of the Kaiga nuclear power plant (NPP), situated ~ 58 km inland of the West Coast of the Indian subcontinent. A grass field was developed exclusively for this study, and two cows of the native breed were raised to graze on it. The soil, grass, and milk were analyzed to evaluate the F
and the F
values for the stable Sr. For comparison, several pasture lands and the cows raised by the villagers and a dairy farm were also studied. The F
values were in the range 0.18-8.6, the geometric mean (GM) being 1.8. The correlations of F
values with a range of physicochemical parameters are presented. The GM values for F
were 2.2 × 10
d L
and 7.2 × 10
d L
for the two cows raised for this study, 2.6 × 10
d L
for those raised by the villagers, and 4.2 × 10
d L
for the dairy farm. The site-specific F
value for the region was determined as 3.2 × 10
d L
. The concentration ratio (CR), defined as the ratio of Sr concentration in milk to that in feed under equilibrium conditions, exhibited less variability (1.8 × 10
-5.4 × 10
) among the three categories of cows.
A novel and efficient Cu-catalyzed one-pot regio- and stereospecific synthesis of benzo1,4,2dithiazine 1,1-dioxides and benzo1,4,2thiaselenazine 1,1-dioxides by cyclization of functionalized ...ynamides with elemental sulfur/selenium has been developed. Its generality is elegantly illustrated by extension to benzodithiazepines and benzothiaselenazepines. Involvement of water in the reaction is demonstrated by the incorporation of 2D at the olefinic site by using D2O in place of water. Selective oxidation at sulfur in benzo1,4,2dithiazine 1,1-dioxide by using mCPBA as the oxidizing agent is also described.
An efficient Cu(
i
)-catalysed cyclisation reaction of 2-iodobenzene sulfonamides with aryl-isothiocyanates and isocyanates that affords functionalised benzodithiazines and benzothiadiazinones, ...respectively, has been developed. Thus, in the reaction with aryl isothiocyanates (Ar-N&z.dbd;C&z.dbd;S), the C&z.dbd;S moiety participates in the cyclisation leading to a
dithiazine
. By contrast, in the case of aryl isocyanates (Ar-N&z.dbd;C&z.dbd;O), the N&z.dbd;C part is involved in the cyclisation and a
thiadiazinone
is obtained. Analogous reactions of isothiocyanates with
N
-tosyl-2-iodo-anilines and 2-iodo-benzyl sulfonamides afford (benzothiazin-2-ylidene)anilines and (benzothiazol-2-ylidene)anilines, respectively. Probable mechanistic pathways are briefly discussed.
Cu(
i
)-catalysed reaction of 2-iodobenzene sulfonamides with aryl isothiocyanates leads to
benzodithiazines
but the corresponding reaction with aryl isocyanates affords
benzothiadiazinones
.
Recent research about Mitsunobo and other reactions is discussed. The Mitsunobu reaction is an important part in the synthesis of many organic transformations.
