Chloro Functions Research Articles

Synthetic strategies, characterization and antimicrobial evaluation of novel angular heteroannulated furo[3,2-g]chromenes

The starting substrate 5-chloro-4,9-dimethoxy-7-oxo-7H-furo[3,2-g]chromene-6-carbonitrile (2) was efficiently synthesized from chlorination of the corresponding hydroxy derivative. The presence of adjacent cyano and chloro functions was employed for construction a variety of five, six and seven membered rings annulated furo[3,2-g]chromenes. Treating precursor 2 with hydrazine, phenylhydrazine and hydroxylamine yielded furo[3,2:6,7]chromeno[4,3-c]pyrazoles 3, 4 and furo[3,2:6,7] chromeno[3,4-d]isoxazole 5, respectively. Also, reaction of compound 2 with a diversity of 1,3-N,N-binucleophiles such as guanidine, cyanoguanidine, thiourea, acetamidine and benzamidine produced annulated furo[3,2:6,7]chromeno[4,3-d]pyrimidines 6–10, respectively. Further, treatment of compound 2 with a variety of 1,4-binucleophiles namely ethylenediamine, o-phenylenediamine and 2-aminophenol yielded furo[3,2:6,7]chromeno[4,3-e][1,4]diazepine 11, furo[3,2:6,7]chromeno[4,3-b][1,5]benzodiazepine 12 and furo[3,2:6,7]chromeno[4,3-b][1,5]benzoxazepine 13, respectively. Some of the synthesized compounds seemed good antimicrobial activity especially compounds 3, 6 and 8. Using analytical and spectral results, the structures of the prepared compounds were established.

Synthesis of Hydrofluoroolefin-Based Iodonium Reagent via Dyotropic Rearrangement and Its Utilization in Fluoroalkylation.

[1,2]‐shift of atoms in alkyl fragments belongs to the class of dyotropic rearrangements. Various atoms, including halogens can be involved in the migration, however participation of iodine is unprecedented. Herein, we report our experimental and DFT studies on the oxidation triggered dyotropic rearrangement of iodo and chloro functions via butterfly‐type transition state to demonstrate the migrating ability of λ3‐iodane centre. With the exploitation of dyotropic rearrangement we designed and synthesized a novel fluoroalkyl iodonium reagent from industrial feedstock gas HFO‐1234yf. We demonstrated that the hypervalent reagent serves as an excellent fluoroalkylation agent for various amines and nitrogen heterocycles.

Synthesis of Hydrofluoroolefin‐Based Iodonium Reagent via Dyotropic Rearrangement and Its Utilization in Fluoroalkylation

Abstract[1,2]‐shift of atoms in alkyl fragments belongs to the class of dyotropic rearrangements. Various atoms, including halogens can be involved in the migration, however participation of iodine is unprecedented. Herein, we report our experimental and DFT studies on the oxidation triggered dyotropic rearrangement of iodo and chloro functions via butterfly‐type transition state to demonstrate the migrating ability of λ3‐iodane centre. With the exploitation of dyotropic rearrangement we designed and synthesized a novel fluoroalkyl iodonium reagent from industrial feedstock gas HFO‐1234yf. We demonstrated that the hypervalent reagent serves as an excellent fluoroalkylation agent for various amines and nitrogen heterocycles.

Gamma Globulins Adsorption on Carbofunctional Polysiloxane Microspheres

Polysiloxane microspheres containing a large number of silanol groups were functionalized by reactions of these groups with organic alkoxy or chlorosilanes having chloro, amine or imidazole functions in their organic parts. The obtained imidazole groups on the microspheres were ionized by the reaction with n-octyl iodide and with methyl iodide while the chloro functions were used for quaternization of a tertiary amine. Adsorption of gamma globulins on these functionalized microspheres was studied in aqueous suspension at pH 5.2, 7.4 and 9.2. Hydrophilic–hydrophobic properties of these microspheres were examined by measuring adsorption of a hydrophobic dye, Rose Bengal. The functionalized microspheres showed higher adsorption of globulins and higher hydrophobicity than the not functionalized ones rich in silanol groups. In the case of microspheres with ionic functional groups the electrostatic forces also contribute to attractive interactions between proteins and microspheres.

Efficient and shortcut syntheses of some novel eight-membered ring cyclitols starting from cycloocta-1,3-diene

Cyclooctane-1,2,3,4-tetraols, aminocyclooctanetriol, and chlorocyclooctanetriol were synthesized starting from cis,cis-1,3-cyclooctadiene by a concise and efficient method. Cyclooctene endoperoxide and cyclooctene epoxide obtained by photooxygenation and epoxidation, respectively, of cis,cis-1,3-cyclooctadiene were used as the key intermediates. The other oxygen, nitrogen, and chloro functionalities were introduced via epoxidation of the remaining double bond, ring-opening of epoxide, and cis-hydroxylation reactions.

PREPARATION AND PROPERTIES OF DIFFERENT FUNCTIONAL GROUP CONTAINING STYRENE BUTADIENE RUBBER

Chemically modified styrene butadiene rubber (SBR) with nitro and chloro functionalities are prepared by the nitromercuration reaction of SBR through a phase transfer catalyst. Activation energy for this chemical reaction calculated from the time temperature data on the chemical reaction by the measurement of percentage of chlorine indicated that the reaction proceeded according to fist order kinetics. The chemical modification is characterized by FTIR, UV, NMR studies reveal the attachment functional group such as nitro and chloro group to the double bond of butadiene moiety. The glass transition temperature of the functionalized SBR is analyzed using differential scanning calorimetry. Thermogravimetric analysis (TGA) of the modified SBR is investigated in order to study the basic decomposition pattern and thermal stability of the materials. Chemical modification of SBR is accompanied by a reduction of double bond which imparts excellent tensile strength. The flame resistances of the modified samples are analyzed by the limiting oxygen index value (LOI) and the result of the studies show that as the level modification increases the tendency of ealstomeric material to burn decreases.

Poly(styrene)comb-b-Poly(ethylene oxide)comb Copolymers: Synthesis and AFM Investigation of Intra- and Supramolecular Organization as Thin Deposits

PScomb-block-PEOcomb copolymers having a poly(chloroethyl vinyl ether)-b-poly(hydroxy ethyl vinyl ether) backbone with polystyrene chains on one side and poly(ethylene oxide) chains on the other, i.e. (PCEVE-g-PS)-b-(POHEVE-g-PEO), were synthesized. The strategy is based on grafting of polystyryllithium onto the reactive chloro functions of the poly(chloroethyl vinyl ether) first block and on grafting polyethylene oxide from the hydroxyl functions of the second block. This procedure allows the preparation of densely grafted amphiphilic diblocklike, Janus-type, comblike copolymers with high molar masses and narrow polydispersity.The characteristics and dimensions of isolated (PCEVE-g-PS)-b-(POHEVE-g-PEO) macromolecules were studied by light scattering in THF, a good solvent of both PS and PEO branches, as well as using AFM imaging of highly diluted deposits. Unimolecular rodlike nano-objects with distinct PS and PEO domains were observed, in agreement with their diblocklike structure. In relation with their amphiphilic nature, the combs can self-assemble in different morphologies. When graphite deposits are made from more concentrated methylene dichloride solutions, the PScomb-b-PEOcomb copolymers self-assemble directly on the substrate, forming flowerlike molecular aggregates interconnected by their PEO moieties. When deposits are made from a selective solvent (methanol) of the PEO comb block, hyperbranched micelles formed in the solution retain their structure on the solid substrate, yielding well-defined spherical objects.

Polymers with Side Chain N‐Alkoxy Pyridinium Ions as Precursors for Photoinduced Grafting and Modification Processes

AbstractA combination of NMP and photoinitiated polymerization is suggested as a new strategy for the synthesis of graft copolymers. First, P(S‐co‐CMS) copolymer backbones with different chloromethyl content are prepared by NMP. The chloro functions are then converted into photosensitive 4‐phenyl pyridinium‐N‐oxide ion functions. Finally, these photoactive polymers are irradiated in the presence of MMA to obtain the graft copolymers. They and their precursors at various stages are characterized by spectroscopy and GPC. It is demonstrated that the irradiation of photoactive polymers in the presence of a hydrogen donors such as THF facilitates the conversion of pyridinium ions to hydroxyl groups.magnified image

A facile radical induced selective removal of N-propargyl protecting groups using low valent titanium reagents

Low valent titanium mediated cleavage of Npropargyl bonds offers a facile, mild, and high yielding method for the deprotection of amines under neutral conditions. The methodology could be used for the chemoselective removal of propargyl groups from amines in preference to the allyl/benzyl counterparts and can be performed chemoselectively in the presence of methoxy, methylenedioxy, and chloro functionalities.

Novel Cyclopentadienyl-Free Organolanthanides: The First Examples of Five-Membered Amidolanthanide Heterocycles.

Reactions of LnCl(3) (Ln = Nd, Gd, Yb) and [{Me(2)SiN(R)Li}(2)] (R = t-Bu, Ph) give the chloride-bridged dimers [{{(t-Bu)NSiMe(2)SiMe(2)N(t-Bu)}Ln(&mgr;-Cl)(THF)}(2)] (1, Ln = Nd; 2, Ln = Gd; 3, Ln = Yb) and [{{(Ph)NSiMe(2)SiMe(2)N(Ph)}Ln(&mgr;-Cl)(THF)(2)}(2)] (4, Ln = Nd; 5, Ln = Gd; 6, Ln = Yb) in good yields. Compounds 2 and 5 were structurally characterized by X-ray crystallography: 2, triclinic, P&onemacr;, a = 10.321(2) Å, b = 11.116(2) Å, c = 13.434(3) Å, alpha = 107.57(3) degrees, beta = 111.31(3) degrees, gamma = 90.67(3) degrees, V = 1356.1(5) Å(3), Z = 1, R = 0.0233; 5, monoclinic, P2(1)/n, a = 13.913(13) Å, b = 12.914(9) Å, c = 16.434(14) Å, beta = 105.64(3) degrees, V = 2843(4) Å(3), Z = 2, R = 0.0281. The chloro functions in 1-6 remain reactive, demonstrated by the isolation of the trifluoroacetate derivatives of 1 and 2. Treatment of 1 or 2 with 2 equiv of NaOCOCF(3) gives [{{(t-Bu)NSiMe(2)SiMe(2)N(t-Bu)}Ln(&mgr;-OCOCF(3))(THF)}(2)] (7, Ln = Nd; 8, Ln = Gd). The structure of 8 was determined by a single-crystal X-ray diffraction analysis. Crystal data for 8: triclinic, P&onemacr;, a = 11.045(2) Å, b = 16.120(3) Å, c = 16.949(3) Å, alpha = 66.17(3) degrees, beta = 85.51(3) degrees, gamma = 78.27(3) degrees, V = 2702.9(9) Å(3), Z = 2, R = 0.0311. The structure of 8 shows the trifluoroacetate group adopting a bridging bidentate mode of coordination.

Chlorosulphation of amino sugars: synthesis of methyl 2-acetamido-4-amino-2,4,6-trideoxy-β-D-glucopyranoside (bacillosamine) from a D-glucosamine derivative

Chlorosulphation of methyl 2-deoxy-2-phthalimido-β-D-glucopyranoside 3 under controlled conditions provided either methyl 6-chloro-2,6-dideoxy-2-phthalimido-β-D-glucopyranoside 4 or methyl 4,6-dichloro-2,4,6-trideoxy-2-phthalimido-β-D-galactopyranoside 5. Chlorination at C-4 occurs to the exclusion of that at C-3, in sharp contrast to the chlorosulphation of methyl β-D-glucopyranoside which is known to give both the 4,6-dichloro-galacto- and 3,6-dichloro-allo-pyranosides. Conversion of the chlorinated phthalimido derivatives 4 and 5 to the corresponding 2-acetamido-2-deoxyhexopyranosides 6 and 7 permitted reduction of the chloro functions by palladium, W-4 Raney nickel, and nickel boride. Reduction of methyl 2-acetamido-6-chloro-2,6-dideoxy-β-D-glucopyranoside 6 by Raney nickel gave methyl 2-acetamido-2,6-dideoxy-β-D-glucopyranoside 8. Selective dechlorination at C-4 was achieved by palladium catalysed reduction of methyl 2-acetamido-4,6-dichloro-2,4,6-trideoxy-β-D-galactopyranoside 7. Nickel boride or Raney nickel reduction of 7 effected selective dechlorination at C-6 to give methyl 2-acetamido-4-chloro-2,4,6-trideoxy-β-D-galactopyranoside 9. Azide displacement of the 4-chloro group of 9 provided a simple route to the 2,4-diamino sugar bacillosamine. A side product of the azide displacement reaction was the unsaturated sugar, methyl 2-acetamido-2,4,6-trideoxy-α-L-threo-hex-4-enopyranoside, 14.