Search results for "Amide"

Syntheses of novelN-([18F]fluoroalkyl)-N-nitroso-4-methyl-benzenesulfonamides and decomposition studies of corresponding19F- and bromo-analogues: pot…

2003

N-([ 18 F]fluoroalkyl)-N-nitroso-4-methyl-benzensulfonamides [n-alkyl = (-CH 2 ) [ 18,19 F]F, n=2-4)] were synthesized in radiochemical yields ranging from 75-90% to provide new secondary labelling precursors for the syntheses of 18 F-labelled compounds. Preliminary decomposition studies utilizing the corresponding non-radioactive 19 F-compounds as well as the bromo containing analogous compounds were performed to evaluate their stability regarding temperature and basicity of the labelling medium. Furthermore, initial difficulties in labelling these compounds led to the development of a modified labelling procedure applying nearly solvent-free conditions. Extensive decomposition experiments…

1983

Introduction des groupes alkyl dans le polyamide commercial Trogamid T. Formation d'anions polyamides par l'hydrure de sodium puis alkylation par les bromures d'alkyle

ChemInform Abstract: Studies on the Biosynthesis of Paraherquamide. Construction of the Amino Acid Framework.

2010

Abstract It has been previously established in this laboratory that the β-methyl-β-hydroxyproline moiety of the potent anthelmintic agent paraherquamide A, is biosynthetically derived from l -isoleucine. The downstream events from l -Ile to paraherquamide A have now been investigated. The synthesis of [1- 13 C]-labeled l -β-methylproline is described by means of a Hoffman–Loeffler–Freytag reaction sequence from [1- 13 C]- l -Ile. This amino acid is shown to be a direct biosynthetic precursor to paraherquamide A by feeding and incorporation experiments in growing cultures of Penicillium fellutanum . Three tryptophan-containing dipeptides of l -β-methylproline have been constructed: [ 13 C 2 …

N-[3-(5-Oxo-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-2-ylamino)phenyl]furan-3-carboxamide

2010

In the title compound, C26H20N2O3, the two aromatic rings of the tricyclic unit are oriented at a dihedral angle of 54.53 (9)°. The crystal structure displays intermolecular N—H...O hydrogen bonding.

Reaktionen bei der Bestrahlung von poly(N-chloramid)en

1980

On irradiating poly(N-chloroamide)s in films or in solution in the range of 325–375 nm carboxamide groups are formed. The irradiated polymer contains chlorine which is linked to C-atoms. This reaction can certainly not be explained with an intramolecular photorearrangement but with a sequence of photoreactions and dark reactions satisfactorily accounting for all observations.

1979

Interaction of pHPMA–pLMA Copolymers with Human Blood Serum and Its Components

2013

Immediately after administration, polymer therapeutics are exposed to complex biological media like blood which may influence and alter their physicochemical properties due to interactions with proteins or serum components. Among such interactions those leading to larger sized aggregates can be sensitively detected by dynamic light scattering (DLS) as a pre in vivo screening method. Random copolymers from N-(2-hydroxypropyl)methacrylamide and lauryl methacrylate p(HPMA-co-LMA) and copolymers loaded with the model drug domperidone were characterized by DLS in isotonic salt solution and in blood serum. The bare amphiphilic copolymer micelles (Rh=30 nm in isotonic salt solution) formed large a…

Enantioselektive Trifluoracetylierung mit Hilfe chiraler Polyamide

1980

(S)-Poly(2-aminobutyric acid) (1) [(S)-poly(imino-1-methyl-3-oxotrimethylene)] was transformed into its N-trifluoroacetyl derivative 4. The IR spectra and the circular dichroism of both substances were compared. In addition, (S)-poly[N-(1-phenylethyl)acrylamide] (2) ((S)-poly-[1-(1-phenylethylaminocarbonyl)ethylene]) was trifluoroacetylated leading to polymer 5. 4 was found to react as trifluoroacetylating agent with L-1-phenylethylamine (L-3) twice as fast as it reacts with D-3. Accordingly, the reaction of 4 with D,L-3 leads preferentially to the L-form of N-(1-phenylethyl)trifluoroacetamide with optical yields up to 6%. The reaction of 5 with D,L-3 affords the D-form of N-(1-phenylethyl)…

α,ω-Functionalized poly-N-isopropylacrylamides: controlling the surface activity for vesicle adsorption by temperature

2003

The synthesis of alpha,omega-end-functionalized copolymers of N-isopropylacrylamide and N-(3-dimethylaminopropyl)acrylamide was performed. Monomer ratios of 100:0, 96:4, and 81:19 were investigated. The lower critical solution temperature (LCST) of these polymers was determined by cloud-point measurements and by microcalorimetric measurements. The LCST increased from 32 over 37 to 47 degrees C as the hydrophobicity increased with increasing amount of comonomer N-(3-dimethylaminopropyl)acrylamide. The polymers could successfully be adsorbed onto gold surfaces. Finally, vesicle adsorption onto these self-assembled polymer films on flat gold surfaces was investigated as the vesicle solution te…

Recycling of dry and wet polyamide 6

2002

Recycling of polycondensation polymers can give rise to secondary materials with good mechanical properties only if a careful drying is carried out before the melt reprocessing operations. The presence of humidity provokes the hydrolytic chain scission of the macromolecules and the consequent decrease of molecular weight and properties. In this work, the drying step was substituted by the addition of an antioxidant that is able to protect the macromolecules because it is the autioxidant is more prone to hydrolysis, thus removing the water from the melt. The mechanical properties of polyamide 6 reprocessed more times in wet conditions and in the presence of this stabilizer are even better th…