Imine

At the first step, complex I is formed by the complexation of KF with catalyst which then forms complex II by reaction with amido sulphone. Subsequently, elimation of the sulfinate group from the amido sulfone affords an imine being activated complex through hydrogen bonding. Subsequent addition of the activated indole to the imine (complex III) then delivers the alkylation products. The enforced proximity of the catalyst and substrates by chiral cage in situ formed by the incorporation of potassium salt can enhance the reactivity and efficiently transfer the stereochemical information, mimicking the action of enzymes. To our delight and suprise, all the proposed intermediates I, II, and III were identified by electrospray ionization high-resolution mass spectroscopy (ESI-HRMS) (the positive ion mode), strongly supporting our proposed mechanism. The peaks at m/z 1228.8160, 1571.9253, and 1546.9745 are consistent with [I – F-], [II - F-], and [III - PhSO2-], respectively. Moreover, the H-bonding interactions of indole…

complex I is formed by the complexation of KF with catalyst, which then cordinates with α-amidosulfone. Subsequently, the elimination of the sulfinate group from α-amidosulfone affords an imine activated through hydrogen bonding as dictated in complex II. The subsequent coordination of potassium enolate (generated in situ from cyclic ketones with KF) to the catalyst (complex III) was followed by its addition to the imine to provide the enantio- and diastereo-enriched adducts (up to 99% ee and up…

Pyridine is a very unreactive aromatic imine The nitrogen atom in the pyridine ring is planar and trigonal with the lone pair in the plane of the ring. This makes it an imine. Most of the imines you have met before (in Chapter 14, for example), have been unstable intermediates in carbonyl group reactions, but in pyridine we have a stable imine—stable because of its aromaticity. All imines are more weakly basic than saturated amines and pyridine is a weak base with a pKa of 5.5. This means that…

Toluene 24 1 5 (R)-1e 1.0 Toluene 59 70 6 (R)-1b 1.0 CH2Cl2 70 95 7 (R)-1b 1.0 1,4-dioxane 52 91 8 (R)-1b 1.0 THF 61 95 9 (R)-1b 1.0 mesitylene 75 98 10 (R)-1b 1.0 m-xylene 76 99 11 (R)-1b 1.2 m-xylene 83 99 [a] Reaction Conditions: 3a (0.2 mmol), 2a (0.2 mmol), KF (0.4 mmol), catalyst (0.02 mmol) in solvent (0.2 mL) at room temperature for 12 h, unless otherwise specified. [b] Isolated yield. [c] Enantiomeric excess (% ee) was determined by chiral HPLC. A wide range of substituted…

Synthesis of 10-Camphorsulfonamide (3) A three-neck flask, with a stir bar was charged with 18.4 mL of concentrated ammonium hydroxide. While on ice and with the stir bar mixing vigorously, 1.88g of 10-(camphorsulfonyl)chloride in 18.4 mL of methylene chloride was slowly over 20 minutes. This mixture was allowed to stir and react for 1.5 hours at 0° Celsius. The phases were then separated. The aqueous phase was washed with methylene chloride twice with 15 mL of methylene chloride. The organic…

contains. For the determination of overall protein concentration there are various methods used such as the Formol titration, Kjeldahl method, Enhanced Dumas method, UV-visible spectroscopy, Biuret method, and Lowry method, Dye binding methods, Turbimetric method and other instrumental techniques. Formol titration was discovered by Blum in 1989. It said that this method seems the fastest and the simplest of the procedures for determining proteins. Blum had found out that when formaldehyde is…

usual quantification techniques due to the presence of solid particles in the solution.16 One method proposed to circumvent this issue was Fourier-Transform Raman spectroscopy, which showed a recovery of 98.2 – 101.2% across four different models.16 This method suffers from the drug molecules not giving the strongest Raman signals.16 Another method proposed utilized the oxidation product of acetaminophen’s reaction to enzymatically quantify the drug.17,18 Acetaminophen undergoes one of three…

1. INTRODUCTION Thiosemicarbazone is a derivative of imine which is formed when an aldehyde/ketone reacts with a thiosemicarbzide through a condensation reaction. The presence of the hetero atoms like Sulphur and Nitrogen makes these derivatives biologically active. Lately, great emphasis is laid on the synthesis and development of these derivatives reason being the wide variety of pharmacological activities exhibited by them. So far, thiosemicarbazones have been shown to exhibit analgesic and…

low swelling property of DMSO into the lipophilic resin 2. To solve this problem, we changed the solvent to a 1:1 mixture of DMSO and THF to increase solvent system’s swelling properties. As a result, 15a was obtained in 56% overall yield after three steps (Table 1, Entry 2). Next, for better reactivity, further modification such as Suzuki coupling was attempted to replace bromine to iodine. From the result of the model study, resin 2 was reacted with 3-bromo-5-iodopyrazin-2-amine 3b in the…

Schiff Bases: Schiff bases are amongst the important class of drugs containing imine or azoethine (-C=N-) moiety,have been obtained by the condensation of primary amines and carbonyl compounds.It was first time presented by the Hugo schiff (Cimerman et al, 2000). Schiff bases are one of the most important class of organic drugs widely used in variety of different fields such as analytical, biological, and inorganic chemistry.The schiff bases heve been designed to synthesize more and more novel…