A Novel Green Synthesis of Thalidomide and Analogs

Thalidomide and its derivatives are currently under investigation for their antiangiogenic, immunomodulative, and anticancer properties. Current methods used to synthesize these compounds involve multiple steps and extensive workup procedures. Described herein is an efficient microwave irradiation green synthesis method that allows preparation of thalidomide and its analogs in a one-pot multicomponent synthesis system. The multicomponent synthesis system developed involves an array of cyclic anhydrides, glutamic acid, and ammonium chloride in the presence of catalytic amounts of 4-N,N-dimethylaminopyridine (DMAP) to produce thalidomide and structurally related compounds within minutes in good isolated yields

(E)-2-{[(Furan-2-ylmethyl)imino]methyl}-4-nitrophenol

In the title compound, C12H10N2O4, the furan-2-ylmethyl group is disordered over two sets of sites, with refined occupancies of 0.858 (3) and 0.143 (3). In the major component of disorder, the dihedral angle between the furan and benzene rings is 63.1 (2) and for the minor component this value is 67.9 (6) . The planes of the nitro group and the attached benzene ring form a dihedral angle of 4.34 (17) . In the crystal, inversion-related molecules are linked by two pairs of weak C—H O interactions, one involving the nitro group and the other involving the O—H group as an acceptor. As a result of these associations, ribbons are formed along [120]. A strong intramolecular O—H N hydrogen bond is observed.National Science Foundation MRI program (CHE0619278)Scopu

Crystal structure of (E)-2-{[(6-meth­oxy-1,3-benzo­thia­zol-2-yl)imino]­meth­yl}phenol

The title compound, C15H12N2O2S, crystallizes in the ortho­rhom­bic space group Pna21, with two mol­ecules in the asymmetric unit (Z′ = 2). Each mol­ecule consists of a 2-hy­droxy Schiff base moiety linked through a spacer to a 2-amino­benzo­thia­zole moiety. Each mol­ecule contains an intra­molecular hydrogen bond between the –OH group and imine N atom, forming a six-membered ring. The two independent molecules are linked by a pair of C—H⋯O hydrogen bonds, forming dimers with an R 2 2(20) ring motif. These dimers are further lined into sheets in the ab plane by weak inter­molecular C—H⋯N inter­actions. The structure was refined as an inversion twinQatar National Research Fund Grant No. NPRP 7–495-1–094

(E)-2-[(2-Hydr­oxy-5-nitro­phen­yl)iminiometh­yl]phenolate

In the title mol­ecule, C13H10N2O4, the dihedral angle between the mean planes of the benzene and phenolate rings is 21.6 (4)°. The nitro O atoms are twisted slightly out of the plane of the ring to which the nitro group is attached [dihedral angle 8.4 (3)°]. The amine group forms an intra­molecular hydrogen bond with both nearby O atoms. An extended π delocalization throughout the entire mol­ecule exists producing a zwitterionic effect in this region of the mol­ecule. The shortened C—O bond [1.2997 (15) Å] in concert with the slightly longer C—OH bond [1.3310 (16) Å] provide evidence for this effect. The crystal packing is influenced by strong inter­molecular O—H⋯O hydrogen bonding. As a result, mol­ecules are linked into an infinite zigzag chain running along the b axis. A MOPAC PM3 calculation provides support to these observations

2-(4-Hy­droxy­phen­yl)-3-(trimethyl­sil­yl)propanaminium chloride

In the title crystal structure, C12H22NOSi+·Cl−, anions and cations are linked via O—H⋯Cl, N—H⋯Cl and N—H⋯O hydrogen bonds to form a two-dimensional network parallel to (101). Within the hydrogen-bonded network, R 4 2(22) ring motifs are stacked along [010]

Natural Dyes in Cyanide and Anion Sensing

Cyanide is one of anions of concern due to its high toxicity. It causes death at a low dosage (2.6 mM) and the allowable level should be lower than 1.9 mmolar according to World health Organization (WHO). Cyanide contamination in the environment comes from many sources as metallurgy, gold mining, cyanide fishing, manufacturing acrylonitriles and related polymers, and natural sources. Cyanide also is present in some foods and food products such as cassava, bitter almonds, apple seeds, and some beans. The wide spread of cyanide in these food is of concern and the levels should be monitored and evaluated. In addition cyanide, may leak and get into water bodies or soil accidentally or intentionally, therefore, developing an easy, simple method for its detection is a priority. Many methods have been developed for detection of cyanide and anions such as titrations, distillations, GC-ECD, and spectrophotometrically. Colorimetric methods have been developed which are easy and simple that can give qualitative results visually and quantitatively using absorption or fluorescence spectroscopy. We have tuned into using dyes and natural dyes that are none toxic and available to use as visual (colorimetric) using both absorption and fluorescence techniques. Curcumin [1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione] is obtained from dry rhizomes of Curcuma longa, as the main yellow pigment used as spices, cosmetic and traditional medicine. It has been reported that curcumin also has many pharmacological functions like antioxygenation, antibiosis and antitumor. Despite the fact that extensive colorimetric and related photophysical studies of curcumin has been extensively studied, less study has done on its potentiality in application as a colorimetric and naked eye sensor of biologically and environmentally important anions like fluoride, acetate and phosphate. Some studies reported interaction of curcumin with cyclodextrin based on changes in basicity in acetonitrile which showed its importance in supramolecular chemistry. We herein describe a simple and efficient visible colorimeric cyanide and fluoride ions detection using commercially available curcumin as a receptor. The method could allow application in detection of curcumin, fluoride and cyanide, important chemical and biological species The choice of curcumin as a sensor for anion was mainly based on the fact that curcumin is a phenol and therefore exist in a equilibrium between its protonated and deprotonated forms in relatively basic media. It also contains a carbonyl group succeptable to nucleophilic addition, this will make it have two anion receptors., hydroxyl for hydrogen bonding to associate with basic anions. The carbonyl is areceptor for nucleophilc anions such as cyanide. Due to this reason curcumin can interact differently with different anions and enhance its selectivity based on the sovent choice. It will behave as a chemodosimeter. Acetonitrile, a polar aprotic solvent is is a good media for the analysis, it does not compete with anion in the recognition sites of curcumin. Variation in color changes of curcumin in acetonitrile was done by addition of aliquots of various anions as tetrabutylammonium salts. Addition of fluoride and cyanide ions induced color change from yellow, purple, blue to deep blue with intensity at every level dependent on the fluoride ion concentration. Acetate ion changed the color of solution to light purple, while dihydrogen phosphate induced only a tinge of color enhancement. Chloride, bromide and perchlorate were found to show no effect on the solution of curcumin. In an aquaeous acetonitrile solution the effect was observed only for cyanide only with a clear color change from yellow to red. While other anions had no significant effect. This indicates that the mechanism of interaction is based on nucleophilic addition in the case of cyanide in aqueous media and hydrogen bonding in nonpeotoc solvents. The stoichiometry was determinned to be 1:1 for cyanide and 1:2 for fluoride. The binding constants and detection limits were calculated form the UV-vis absorption titrations. In this presentation the method, structures of dye and complexes, the titration curves, color changes, binding constants and aplication will be discussed.qscienc

3-Aminopyridine Salicylidene: A Sensitive and Selective Chemosensor for the Detection of Cu(II), Al(III), and Fe(III) with Application to Real Samples

Interest in developing selective and sensitive metal sensors for environmental, biological, and industrial applications is mounting. The goal of this work was to develop a sensitive and selective sensor for certain metal ions in solution. The goal was achieved via (i) preparing the sensor ((E)-2-((pyridine-3-ylimino)methyl)phenol) (3APS) using microwave radiation in a short time and high yield and (ii) performing spectrophotometric titrations for 3APS with several metal ions. 3APS, a Schiff base, was prepared in 5 min and in a high yield (95%) using microwave-assisted synthesis. The compound was characterized by FTIR, XRD, NMR, and elemental analysis. Spectrophotometric titration of 3APS was performed with Al(III), Ba(II), Cd(II), Co(II), Cu(II), Fe(III), Mn(II), Ni(II), and Zn(II). 3APS showed good abilities to detect Al(III) and Fe(III) ions fluorescently and Cu(II) ion colorimetrically. The L/M stoichiometric ratio was 2:1 for Cu(II) and 1:1 for Al(III) and Fe(III). Low detection limits (μg/L) of 324, 20, and 45 were achieved for Cu(II), Al(III), and Fe(III), respectively. The detection of aluminum was also demonstrated in antiperspirant deodorants, test strips, and applications in secret writing. 3APS showed high fluorescent selectivity for Al(III) and Fe(III) and colorimetric selectivity towards Cu(II) with detection limits lower than corresponding safe drinking water guidelines.This work was made possible by NPRP grant # 7-495-1-094 from the Qatar National Research Fund (a member of Qatar Foundation). The findings achieved herein are solely the responsibility of the authors. The authors also acknowledge the support of Qatar University through grant # QUCG-CAS-20/21-1

3-(2,6-Dioxopiperidin-3-yl)-3-aza­bicyclo­[3.2.0]heptane-2,4-dione

The title mol­ecule, C11H12N2O4, consists of a 3-aza­bicyclo­[3.2.0]heptane group containing a nearly planar cyclo­butane ring (r.m.s. deviation of fitted atoms is 0.0609 Å), fused to a pyrrolidine ring, bonded to a 2,6-dioxopiperidine ring at the 3-position. The angle between the mean planes of the cyclo­butane and fused pyrrolidine ring is 67.6 (6)°. The dihedral angles between the mean planes of the pyrrolidine and cyclo­butane rings and the dioxopiperidine ring are 73.9 (2) and 62.4 (4)°, respectively. The pyrrolidine and dioxopiperidine rings are twisted about the 3-yl group [torsion angles = −55.0 (1) and 115.0 (1)°] in a nearly perpendicular manner. Crystal packing is influenced by extensive inter­molecular C—H⋯O and N—H⋯O inter­actions between all four carbonyl O atoms and H atoms from the cyclo­butane and dioxopiperidine rings, as well as between the N atom and an H atom from the cyclo­butane ring. In addition, weak π-ring interactions also occur between H atoms from the cyclobutane ring and the five-membered pyrrolidine ring. As a result, mol­ecules are linked into infinite chains diagonally along the [101] plane of the unit cell in an alternate inverted pattern

(E)-2-[(2-Hydr­oxy-5-nitro­phen­yl)iminiometh­yl]-4-nitro­phenolate

The title mol­ecule, C13H9N3O6, consists of a 2-hydr­oxy-5-nitro­phenyl­iminio group and a 4-nitro­phenolate group bonded to a methyl­ene C atom with both of the planar six-membered rings nearly in the plane of the mol­ecule [dihedral angle = 1.3 (4)°]. Each of the nitro O atoms is twisted slightly out of the plane of the mol­ecule. The amine group forms an intra­molecular hydrogen bond with both nearby O atoms, each of which has partial occupancy of attached H atoms [0.36 (3) and 0.64 (3)]. An extended π-delocalization throughout the entire mol­ecule exists producing a zwitterionic effect in this region of the mol­ecule. The shortened phenolate C—O bond [1.2749 (19)°], in concert with the slightly longer phenol C—O bond [1.3316 (19) Å], provides evidence for this effect. The crystal packing is influenced by extensive strong inter­molecular O—H⋯O hydrogen bonding between the depicted phenolate and hydr­oxy O atoms and their respective H atoms within the π-delocalized region of the mol­ecule. As a result, mol­ecules are linked into an infinite polymeric chain diagonally along the [110] plane of the unit cell in an alternate inverted pattern. A MOPAC AM1 calculation provides support for these observations

2-Phenyl-3-(trimethyl­sil­yl)propan-1-aminium chloride

The title compound, C12H22NSi+·Cl−, contains two formula units in the asymmetric unit and is a hydro­chloride salt in which the amine N atom is protonated and the NH3 + group forms hydrogen bonds with the Cl− anion, forming a ribbon in the c-axis direction