Substituted N (substituted + n)

Distribution by Scientific Domains


Selected Abstracts


Synthesis and dissociation of amine-blocked diisocyanates and polyurethane prepolymers

POLYMER INTERNATIONAL, Issue 3 2002
T Philip Gnanarajan
Abstract Substituted N -methylanilines are shown to act as blocking agents for toluenediisocyanate. N -methylaniline-, N -methyl- p -anisidine- and N -methyl- p -nitroaniline-blocked toluene diisocyanates have been prepared and characterized by FTIR, 1H NMR and 13C NMR spectroscopies, and nitrogen content analysis. A new method for determining the minimum deblocking temperature of the blocked isocyanate is described. The method has advantages in that it can be used to find the minimum deblocking temperature of even non-volatile blocking agents. The minimum deblocking temperature of the adducts is found to be in the following order: N -methyl- p -anisidine,TDI adduct,<,N -methyaniline,TDI adduct,<,N -methyl- p -nitroaniline,TDI adduct. The anilines exhibit the same trend when they block a polyurethane prepolymer prepared using polypropylene glycol of molecular weight 2000,g,mol,1 and tolylene-2,6-diisocyanate. The deblocking temperatures are lower in the case of blocked prepolymers than in the blocked adducts. The blocked adducts and prepolymers are reacted with pyromellitic dianhydride (PMDA) in dimethylpropylene urea (DMPU) and the evolution of carbon dioxide is monitored to study the completion of imidization. The reaction time is in accordance with the deblocking ability of the adducts. The regeneration of the blocking agent is confirmed by gas chromatography. © 2002 Society of Chemical Industry [source]


Synthesis, structure and muscarinic agonist activity of substituted N -(silatran-1-ylmethyl)acetamides

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2010
Vera G. Pukhalskaya
Abstract Substituted N -(silatran-1-ylmethyl)acetamides, N -methyl- N -[1-(3,,7,,10,-trimethylsilatran-1-yl)methyl]acetamide (2a) and N -(2-hydroxyethyl)- N -[1-(3,,7,,10,-trimethylsilatran-1-yl)methyl]acetamide (2b) were prepared by the reactions of triisopropanolamine with N -methyl- N -(trimethoxysilylmethyl)acetamide (1a) and 2,2-dimethoxy-4-acetyl-1-oxa-4-aza-2-silacyclohexane (1b), respectively. According to X-ray data, the structures of the silatrane moieties are superpositions of unsymmetrical and symmetrical stereoisomers. The O , Si coordination between the central atom and exocyclic substituent is absent in both compounds. Silatranes 2a and 2b are partial muscarinic agonists which demonstrate submaximal effect and mimic the effect of acetylcholine by binding directly to cholinoreceptors of the ileal smooth muscle. Copyright © 2009 John Wiley & Sons, Ltd. [source]


ChemInform Abstract: Synthesis of Substituted N-[4(5-Methyl/Phenyl-1,3,4-oxadiazol-2-yl)-3,6-dihydropyridin-1(2H)-yl] benzamide/benzene Sulfonamides as Antiinflammatory and Anticancer Agents.

CHEMINFORM, Issue 37 2009
Madhavi Gangapuram
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]


Straightforward Synthesis of ,-Substituted Prolines by Cross-Metathesis

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2008
Marco Lumini
Abstract The synthesis of several ,-substituted N -Boc-protected prolines has been achieved by cross metathesis (CM) of N -Boc-allylproline 5 with terminal long chain alkenes and alkenes bearing hydroxy, silyloxy, ester, and O -acetylglucosamido groups. The CM occurred with good selectivity and short reaction time under microwave heating conditions, affording yields in the range of 40,92,%. Addition of Ti(OiPr)4 as a Lewis acid allowed a slight increase of the yield in the case of alkenes with Lewis basic substituents. The CM was also successfully applied to allylproline protected with trichloroacetaldehyde 4, but the intermediate products were less practical for further deprotection and elaboration. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]


Synthesis of Some New Substituted Photochromic N,N, -Bis(spiro[1-benzopyran-2,2,-indolyl])diazacrown Systems with Substituent Control over Ion Chelation

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2006
Craig J. Roxburgh
Abstract The reversible photochemical ion chelation of the newly synthesised substituted N,N, -bis(spiro[1-benzopyran-2,2,-indolyl])diazacrown systems 15a,c and the subsequent molecular electronic control of this process using appropriately placed substituent groups on the spiro-benzopyran skeleton is reported. The principle of molecular electronic control of ion chelation is demonstrated by comparing the behaviour of the newly synthesised nitro-substituted and pyrido-annulated spiro-benzopyran system 9b with that of the unsubstituted compound 9a. Electronic substituent control over ion chelation is then exemplified for the new N,N, -bis(5,-nitrospiro[1-benzopyran-2,2,-indolyl])diazacrown system 15c and further exemplified for the corresponding 5,-trifluoromethyl derivative 15b, which contains the photochemically more robust trifluoromethyl group. The crown system 15a, unsubstituted in the spiro-indole moiety, is also reported. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]


A Mild and Efficient Method for N -Arylnucleobase Synthesis via the Cross-Coupling Reactions of Nucleobases with Arylboronic Acids Catalyzed by Simple Copper Salts

HELVETICA CHIMICA ACTA, Issue 6 2008
Lan Tao
Abstract A simple and efficient copper-salt catalyzed N -arylation of nucleobases is reported. In a mixed solvent of MeOH and H2O, the coupling products were obtained in moderate to excellent yields at room temperature within a short time. A variety of substituted N -aryl nucleobases can be prepared through this procedure. [source]


Iron-Catalyzed Oxidative Mono- and Bis-Phosphonation of N,N -Dialkylanilines

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010
Wei Han
Abstract The dehydrogenative ,-phosphonation of substituted N,N -dialkylanilines by dialkyl H -phosphonates was achieved under mild conditions by using environmentally benign iron(II) chloride as catalyst and tert -butyl hydroperoxide as oxidant. The reaction proceeded in the presence of electron-donating (methoxy, methyl, benzyl) and electron-withdrawing ring-substitutents (bromo, carbonyl, carboxyl, m -nitro) in moderate to good yields. The X-ray crystal structure of N -(5,5-dimethyl-2-oxo-2,5 -[1,3,2]dioxaphosphinan-2-yl-methyl)- N -methyl- p -toluidine was determined. Bis-(4-(dimethylamino)phenyl)methane and bis-4,4,-(dimethylamino)benzophenone underwent bisphosphonation selectively by respective monophosphonation at the remote dimethylamino groups. Furthermore, the use of excess dialkyl H -phosphonate and oxidant allowed us to functionalize both methyl groups of N(CH3)2 in N,N -dimethyl- p -toluidine and N,N -dimethylaminomesidine, respectively, to obtain ,,,,-bisphosphonatoamines in high yield. [source]


A Simple Copper-Catalyzed Cascade Synthesis of 2-Amino-1H -indole-3-carboxylate Derivatives

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2010
Xiaobo Yang
Abstract We have developed a simple and efficient copper-catalyzed method for the synthesis of 2-amino-1H -indole-3-carboxylate derivatives via cascade reactions of substituted N -(2-halophenyl)-2,2,2-trifluoroacetamide with alkyl 2-cyanoacetate or malononitrile under mild conditions, and the method is of wide practical application. [source]


Hydrogen-bonding patterns in three substituted N -benzyl- N -(3- tert -butyl-1-phenyl-1H -pyrazol-5-yl)acetamides

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2010
Gerson López
The molecules of N -(3- tert -butyl-1-phenyl-1H -pyrazol-5-yl)-2-chloro- N -(4-methoxybenzyl)acetamide, C23H26ClN3O2, are linked into a chain of edge-fused centrosymmetric rings by a combination of one C,H...O hydrogen bond and one C,H...,(arene) hydrogen bond. In N -(3- tert -butyl-1-phenyl-1H -pyrazol-5-yl)-2-chloro- N -(4-chlorobenzyl)acetamide, C22H23Cl2N3O, a combination of one C,H...O hydrogen bond and two C,H...,(arene) hydrogen bonds, which utilize different aryl rings as the acceptors, link the molecules into sheets. The molecules of S -[N -(3- tert -butyl-1-phenyl-1H -pyrazol-5-yl)- N -(4-methylbenzyl)carbamoyl]methyl O -ethyl carbonodithioate, C26H31N3O2S2, are also linked into sheets, now by a combination of two C,H...O hydrogen bonds, both of which utilize the amide O atom as the acceptor, and two C,H...,(arene) hydrogen bonds, which utilize different aryl groups as the acceptors. [source]


Synthesis, structure and muscarinic agonist activity of substituted N -(silatran-1-ylmethyl)acetamides

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2010
Vera G. Pukhalskaya
Abstract Substituted N -(silatran-1-ylmethyl)acetamides, N -methyl- N -[1-(3,,7,,10,-trimethylsilatran-1-yl)methyl]acetamide (2a) and N -(2-hydroxyethyl)- N -[1-(3,,7,,10,-trimethylsilatran-1-yl)methyl]acetamide (2b) were prepared by the reactions of triisopropanolamine with N -methyl- N -(trimethoxysilylmethyl)acetamide (1a) and 2,2-dimethoxy-4-acetyl-1-oxa-4-aza-2-silacyclohexane (1b), respectively. According to X-ray data, the structures of the silatrane moieties are superpositions of unsymmetrical and symmetrical stereoisomers. The O , Si coordination between the central atom and exocyclic substituent is absent in both compounds. Silatranes 2a and 2b are partial muscarinic agonists which demonstrate submaximal effect and mimic the effect of acetylcholine by binding directly to cholinoreceptors of the ileal smooth muscle. Copyright © 2009 John Wiley & Sons, Ltd. [source]