Synthesis of Novel 2-Iminothiazolidin-4-ones

Abstract

Thiazolidin-4-ones are known to exhibit diverse biological activities such as antimicrobial, anticancer, antidiarrheal, anticonvulsant, antidiabetic, antihistaminic, and antifungal activities. In the present investigation, a series of 2-haloacetamides was prepared by reacting chloroacetyl chloride with amines in dry benzene under reflux conditions. The formed 2-haloacetamides reacted with potassium thiocyanate in refluxing dry acetone to afford new 2-iminothiazolidin-4-ones. The 5-arylidene-2-imino-3 (napthalen-2yl)-thiazolidin-4-ones were prepared by condensing 2-iminothiazolidin-4-ones with substituted benzaldehydes. All the products were characterized by infrared, mass, and ¹H and ¹³C NMR techniques.     

Tandem Ring Opening and Oximation of Ethyl 3‐Aroyl‐1‐cyano‐4‐hydroxy‐2,4,6‐triarylcyclohexanecarboxylate by Hydroxylamine

The reaction of hydroxylamine hydrochloride with ethyl 3‐aroyl‐1‐cyano‐4‐hydroxy‐2,4,6‐triarylcyclohexanecarboxylate has led to the formation of ethyl 2‐[amino(hydroxyimino)methyl]‐3‐aryl‐5‐(hydroxyimino)‐5‐arylpentanoate via a tandem ring opening and oximation process. The structures of the products are confirmed by NMR and X‐ray techniques, and the conformational features of the product arrived at are compared with a molecular dynamics simulation study.     

SYNTHESIS AND SPECTRAL CHARACTERIZATION OF DIETHYL 2-[ARYL(4-ARYL-1,2,3-SELENADIAZOL-5-YL)METHYL]MALONATE

Synthesis and characterization of several diethyl 2-[aryl(4-aryl-1,2,3-selenadiazol-5-yl)methyl]malonates are reported.     

Impurity Profile Study of Venlafaxine Hydrochloride,an Antipsychotic Drug Substance

Venlafaxine hydrochloride is a phenyl ethylamine derivative, used for the treatment of depression. During the process development of venlafaxine hydrochloride, six process-related potential impurities were detected in high-performance liquid chromatography. All these impurities were identified, synthesized, and subsequently characterized by their respective spectral data (IR, mass, ¹H NMR, and ¹³C NMR) as described in this article.     

Iron(III) bis-complexes of Schiff bases of S-methyldithiocarbazates: Synthesis,structure, spectral and redox properties and cytotoxicity

A series of iron(III) bis-complexes of the type [FeL₂]X 1-4 , X = OH⁻ ( 1 ), Cl^¯ ( 3 ), and FeCl₄^¯ ( 2 , 4 ), where LH is a tridentate (N,N,S) ligands such as N′-(1-pyridin-2-ylethylidene)-hydrazinecarbodithioic acid methyl ester ( HL1 ), N′-(phenylpyridin-2-ylmethylene)-hydrazinecarbodithioic acid methyl ester ( HL2 ), N′-quinolin-2-ylmethylene-hydrazinecarbodithioic acid methyl ester ( HL3 ), or N′-(1-methyl-1H-imidazol-2-yl-methylene)hydrazinecarbodithioic acid methyl ester ( HL4 ) has been isolated in moderate to good yields and completely characterized by elemental analyses, conductivity studies, and infrared and UV-visible spectral measurements. The single crystal X-ray structures of 1 , 2 and 4 revealed that two deprotonated tridentate (NNS) ligands are meridionally coordinated to constitute a distorted octahedral coordination geometry around iron(III). In acetonitrile solution, all the complexes show quasi-reversible Fe(III)/Fe(II) redox behavior. The in vitro cytotoxicity of the ligands HL1–HL4 (IC₅₀: HL1 , 64.5; HL2 , 51.0; HL3 , 124.0; HL4 , 45.0 μM at 24 h) and complexes 1–4 (IC₅₀: 1 , 84.5; 2 , 40.0; 3 , 168.5; 4 , 50.5 μM at 24 h) towards A549 lung cancer cell lines are similar to cisplatin (69.0 μM), revealing that free ligands cause cancer cell death with potency higher than the corresponding iron(III) complexes. Also, both the ligands and the complexes cause cell death mainly through apoptotic mode, as revealed by the observation of a higher percentage of apoptotic cells in acridine orange (AO)/ ethidium bromide (EB), and Annexin V-Cy3 stained cancer cells.     

Two biologically active thio­phene‐3‐carbox­amide derivatives

The compounds 2‐{[(E)‐(4‐methoxy­phenyl)­methyl­ene]­amino}‐N‐(3‐methyl­phenyl)‐4,5,6,7‐tetra­hydro‐1‐benzo­thio­ph­ene‐3‐carbox­amide, C₂₄H₂₄N₂O₂S, (I), and N‐(4‐meth­yl­phenyl)‐2‐{[(E)‐(4‐methyl­phenyl)­methyl­ene]­amino}‐4,5,6,7‐tetra­hydro‐1‐benzo­thio­phene‐3‐carbox­amide, C₂₄H₂₄N₂OS, (II), show antibacterial and antifungal activities. The m‐toluidine ring in (I) and the p‐toluidine ring in (II) are coplanar with their respective thio­phene rings. In (I), an intermolecular C—H⋯O hydrogen bond is present, whereas (II) does not exhibit any significant intermolecular interactions. However, in both compounds, an intramolecular N—H⋯N hydrogen bond forms a pseudo‐six‐membered ring, thus locking the molecular conformation and eliminating conformational flexibility.     

Biocatalytic deracemization of alkyl-2-hydroxy-4-arylbut-3-ynoates using whole cells of Candida parapsilosis ATCC 7330

Racemic alkyl-2-hydroxy-4-arylbut-3-ynoates were deracemized to the (S)-alkyl-2-hydroxy-4-arylbut-3-ynoates in excellent enantiomeric excesses (up to >99%) and good isolated yields (up to 81%) with the biocatalyst Candida parapsilosis ATCC 7330. The absolute configuration of the resulting enantiomer was assigned by ¹H NMR using Mosher’s method.     

XRD and AFM studies of ZnS thin films produced by electrodeposition method

The structure and morphology of ZnS thin films were investigated. ZnS thin films have been grown on an indium tin oxide glass substrate by electrodeposition method using zinc chloride and sodium thiosulfate solutions at room temperature. The X-ray diffraction patterns confirm the presence of ZnS thin films. From the AFM images, grain size decreases as the cathodic potential becomes more negative (from ?1.1 to ?1.3 V) at various deposition periods. Comparison between all the samples reveals that the intensity of the peaks increased, indicating better crystalline phase for the films deposited at ?1.1 V. These films show homogeneous and uniform distribution according to AFM images. On the other hand, XRD analysis shows that the number of ZnS peaks increased as deposition time was increased from 15 to 30 min at ?1.1 V. The AFM images show thicker films to be formed at ?1.1 V indicating more favourable condition for the formation of ZnS thin films.     

Estimation of Olefin Dimerisation Products by GC/GC–MS and IR Techniques

A GC and IR based protocol was developed for monitoring the isobutene dimerisation process wherein the complete characterisation of the products was carried out by GC coupled with mass spectrometry. In the dimerisation process, LPG from FCC process comprising a mixture of saturated and unsaturated C4 hydrocarbons is subjected to a dimerisation process using a catalyst to produce C8 hydrocarbons. The reaction is carried out keeping in view the demand for high-octane blending components in gasoline. The isooctene generated in the process (mainly from the dimerisation of isobutene) is converted into isooctane having the RON and MON value 100. The monitoring process requires the use of two different column chemistries, viz., a 100 m CPSIL PONA CB non-polar column for C8 and its isomers and an Alumina PLOT column for C4 hydrocarbons. A 100 m non-polar column does not separate the C4 mixture since the column is meant for gasoline range products containing C5 and above hydrocarbons. Therefore, a need was felt for an improvised method which can handle both the analyses simultaneously. A cryogenic oven program starting from 0 °C was developed for separating the isomers of C4 hydrocarbons and C8 hydrocarbons on a single column during the single run by Detailed Hydrocarbon Analyzer. The data obtained using the cryo programme was validated with data obtained using Alumina PLOT column on C4 mixture since the Alumina PLOT column is the widely accepted column chemistry for separating the C4 hydrocarbons. An IR method for the estimation of the total olefin content was developed using 2,2,4-trimethyl pentene-1 as the reference standard. The total olefins generated during the process were identified by GC–MS, quantified by DHA-FID and validated by infrared spectroscopy. A good correlation was found between GC and IR spectral results (correlation coefficient R ²  = 0.99).