Kinetics and mechanism of chloramine-T oxidation of cinnamaldehyde in two acid media

Kinetics of oxidation of cinnamaldehyde (Cinn) by chloramine-T (CAT) has been studied in solutions containing HCl and H₂SO₄ at 313 K. The respective experimental rate laws obtained in HCl and H₂SO₄ media are as follows: and Here the value of x varies from 0.9 to zero while the values of y and z are 0.83 and 0.72, respectively. Effects, on the reaction rate, of ionic strength, reaction product (p-toluenesulfonamide), dielectric constant of the solvent medium, and the anions, Cl⁻ and SO₄²⁻, have been investigated. Activation parameters have been computed, based on the rate constants determined at different temperatures. Mechanisms proposed and the rate laws derived are consistent with the observed kinetic data represented by the experimental rate laws.     

Some analytical applications of aromatic sulfonyl haloamines: Determination of thiocyanate and cyanide ions in metal complexes and salts with bromamine-B and dichloramine-B

Simple, rapid, and reproducible methods for the determination of thiocyanate and cyanide ions in metal salts and complexes with bromamine-B (BAB) and dichloramine-B (DCB) have been developed. The oxidation involves eight and two electron changes, respectively, with NCS^? and CN^? ions in 0.05–0.20 N NaOH medium in the case of BAB and in partially aqueous medium with DCB. The proposed methods could be employed for computing the number of thiocyanate and cyanide ligands present in the respective metal complexes.     

Some analytical applications of aromatic sulfonyl haloamines: Determination of thiocyanate and cyanide ions in metal complexes and salts and thiosemicarbazide in metal complexes with bromamine-T

A simple, rapid, and accurate method for the determination of thiocyanate and cyanide ions in metal complexes and salts, and thiosemicarbazide (TSC) in Zn, Cd, Hg, Ni, Pt, and Pd metal complexes with excess of bromamine-T has been developed. The oxidation involves eight- and two-electron changes, respectively, with NCS^? and CN^? ions and a 12-electron stoichiometry per TSC molecule, in 0.1–0.2 N NaOH medium. The proposed method could be employed for computing the number of thiocyanate, cyanide, and TSC ligands in the respective complexes. The aromatic sulfonyl haloamine, bromamine-T, has been prepared and characterized by uv, ir, and FT NMR ¹H and ¹³C spectral data and its mass spectrum.     

Crystal and Molecular Structure Studies of 1′-Benzyl-8-(4-fluorobenzyl)-8-azaspiro[bicyclo-[3.2.1]octane-3,4′-imidazolodine]-2′,5′-dione

Abstract  

The title compound, C₂₃H₂₃FN₃O₂ has been synthesized and the structure was investigated by X-ray diffraction studies. The compound crystallizes in the triclinic crystal class in the space group P[`1]P\overline{1} with cell parameters a = 9.345(2) ?, b = 10.940(3) ?, c = 11.986(4) ?, α = 72.349(6)°, β = 68.106(18)°, γ = 66.867(5)°, Z = 2 and V = 1027.8(5) ?³. The hydantoin ring adopts a planar conformation and is affected by the π conjugation. The pyrrolidine and piperidine rings in the bicyclo octane moiety adopt envelope and chair conformations respectively. The structure exhibits both inter and intramolecular hydrogen bonds of the type N–H···O, C–H···O and C–H···N. One of the oxygen atoms attached to the hydantoin ring simultaneously accepts two hydrogen bonds to form a three centered hydrogen bonding pattern.     

A facile and expeditious approach for the synthesis of 2-azetidinone derivatives via a multicomponent reaction

Abstract  

New organic reactions allow chemical transformations which were previously unknown. Therefore, new reactions are important contributions to progress in the field of organic synthesis. Herein, we are reporting a simple, one-pot, efficient three-component synthesis of novel 3-chloro-4-[4-(2-oxo-2H-chromen-4-ylmethoxy)phenyl]-1-phenylazetidin-2-one derivatives using 4-(2-oxo-2H-chromen-4-ylmethoxy)benzaldehydes, anilines, and chloroacetyl chloride in the presence of triethyl amine as a catalyst under different conditions. Taking into account environmental and economic considerations, the protocol presented here has the merits of simple operation, convenient work-up, being environmentally benign, and providing good yields. The synthesized compounds were characterized by IR, ¹H NMR, ¹³C NMR, MS, and elemental analysis.     

New Schiff's Base and 2-Azetidinone Derivatives of 3-Benzo[4,5]imidazo[2,1-b]thiazol-3-yl-chromen-2-one by Vilsmeier–Haack Formylation

A new Schiff's base and 2-azetidinone derivatives obtained via the corresponding 3-benzo [4,5] imidazo [2,1-b] thiazol-3-yl-chromen-2-one by Vilsmeier–Haack formylation scaffold is described. Our design is aimed at obtaining new triheterocyclic and tetraheterocyclic derivatives.     

Enantioselective Reactions of N‐Acyliminium Ions Using Chiral Organocatalysts

N‐acyliminium ions are reactive intermediates that can act as electron‐deficient electrophiles toward weak or soft nucleophiles, thereby providing useful methods for both intermolecular‐ and intramolecular carbon–carbon and carbon–heteroatom bond formation. Nucleophilic additions to N‐acyliminium ions constitute an important method for providing α‐functionalized amino compounds and many other biologically active nitrogen‐containing heterocycles. The development of efficient catalytic asymmetric reactions is a key objective in modern organic chemistry and is very important for the synthesis of natural products, pharmaceuticals, and agrochemicals. Various methods are available for this purpose and mostly rely on the use of chiral catalysts for enantioselective synthesis. This review deals with one aspect of such catalysis, which has emerged only in the past few years, and its applications in enantioselective reactions of N‐acyliminium ions to provide various nitrogen‐containing heterocycles.     

Spectrophotometric methods for the determination of certain catecholamine derivatives in pharmaceutical preparations

Two simple, rapid and sensitive spectrophotometric methods for the determination of catecholamine derivatives (pyrocatechol, dopamine, levodopa and methyldopa) are developed. The first method involves the oxidation of o-dihydroxybenzene derivatives by N-bromosuccinimide followed by oxidative coupling with isoniazid leading to the formation of a red-coloured products of maximum absorbance (lambda(max)=480-490 nm). The second method is based on the formation of green to blue complex (lambda(max)=635-660 nm) between o- dihydroxybenzene derivatives and sodium nitroprusside in the presence of hydroxylamine hydrochloride. All measurements of the two procedures are carried out in an alkaline medium at room temperature. The two methods are successfully applied for the determination of dopamine hydrochloride, levodopa and methyldopa in injections and tablets of pharmaceutical preparation. The common excipients used as additives in pharmaceuticals do not interfere in the proposed methods. The reliability of these methods are established by parallel determination with the reported and official methods.     

T3P catalyzed one pot three-component synthesis of 2,3-disubstituted 3H-quinazolin-4-ones

An efficient methodology for the synthesis of 2,3-disubstituted 3H-quinazolin-4-ones is described via one-pot three component reaction from anthranilic acid using T3P as catalyst. Mild reaction conditions, short reaction time, broad functional group tolerance, easy isolation of products and good yields are main advantages of this protocol.