Search results for "nuclear magnetic resonance"

Polycondensed nitrogen heterocycles. Part19. Pyrrolo[1,2-f]phenanthridines by pschorr-type cyclization brought about by hypophosphorous acid

1986

Pyrrolo[1,2-f]phenanthridines were prepared in good yields by the diazotization in acetic acid of the amines la,b and subsequent treatment with hypophosphorous acid. The necessity for hypophosphorous acid in the reaction was demonstrated.

Trichomonazide Wirkstoffe, 5. Mitt. (Dichloranilino)ethentricarbonitrile

1986

Inverse correlated 1H-13C in vivo NMR as a probe to follow the metabolism of unlabeled vanillin by plant cell cultures

1997

Abstract Inverse correlated 2D 1H-13C NMR spectroscopy was used to follow the metabolism of vanillin (1) in vivo by plant cell suspension cultures of Nicotiana plumbaginifolia at the natural abundance of 13C. Under the non-invasive conditions four products could be detected: vanillylalcohol (2), vanillinglucoside (3) and the phenolic and benzylic glucosides of vanillylalcohol (4 and 5).

Conformational study of methyl esters of some aliphaticerythro- andthreo-dichlorocarboxylic acids

1984

The average conformations of methyl esters of some aliphatic erythro- and threo-dichlorocarboxylic acids in dilute carbon tetrachloride solutions have been determined from the vicinal proton–proton coupling constants and 1H NMR shifts. The 13C shift differences between the erythro and threo forms are compared and discussed with regard to the differences in the average conformations.

13C NMR spectroscopic study of diphenyl ether and 28 of its polychlorinated derivatives

1993

The 13 C NMR chemical shifts and coupling constants for diphenyl ether and 28 environmentally interesting polychlorinated diphenyl ethers were measured and analysed

NMR-Spektroskopie an Heterocyclen, 6. Mitt. Favorskii-Umlagerung von α-Brom-β-methoxy-ketonen bei der Imidazol-Cyclisierung in flüssigem Ammoniak

1979

Bei der Imidazolsynthese aus α-Bromketonen und Formiminoethylester in flussigem Ammoniak werden α-alkylsubstituierte Buttersaure-Amide als Nebenprodukte erhalten, deren Entstehen einer Favorskii-Umlagerung zugeschrieben wird. Die isolierten Verbindungen wurden NMR-spektroskopisch untersucht. NMR Spectroscopy of Heterocycles. VI: Favorskii Rearrangement of α-Bromo-β-methoxy Ketones During Imidazole Cyclisation in Liquid Ammonia. During imidazole synthesis with α-bromo ketones and formiminic ethyl ester in liquid ammonia α-alkylbutyric amides were obtained as by-products. Their formation is attributed to a Favorskii rearrangement. The compounds were investigated by NMR spectroscopy.

Cyclic Sulfonimidates by Dynamic Diastereomer-Differentiating Cyclisation: Large-Scale Synthesis and Mechanistic Studies

2001

A dynamic diastereomer differentiating cyclisation is the key step in a new large-scale synthesis of both enantiomers of the cyclic sulfonimidates 1 (Aldrich no. 54099-4) and ent-1 (Aldrich no. 54412-4). These are valuable starting materials in the asymmetric synthesis of chiral oxa- and azaheterocyclic compounds. NMR spectroscopic studies on the reacting system reveal N-chloro sulfinamides to be reactive intermediates in the oxidative chlorination of sulfinamides with tert-butyl hypochlorite and allow for the inspection of the configurational behaviour of the involved sulfonimidoyl chlorides and sulfonimidoyl bromides.

Antimykotische wirkstoffe. XXI. Aliphatisch und alicyclisch substituierte chlor-diallylamino-1l,3,5-triazine

1988

Aus der nucleophilen Substitution eines Chloratoms in 2,4-Dichlor-6-(diallylamino)-1,3,5-triazin (1) durch Amine (2a-g) gehen die Alkylamino- und Cycloalkylamino-chlor-(diallylamino)-1,3,5-triazine (3a-g) hervor. Von den zur Untermauerung des Strukturtyps 3 herangezogenen spektroskopischen Daten sind besonders charakteristisch die durch das 1,3,5-Triazinringsystem hervorgerufene IR-Bande bei 800 cm−1, die den Allylgruppen zuzuordnenden vier 1H-NMR-Signale zwischen 4,1–6,1 ppm und das beim massenspektroskopischen Abbau auftretende Rumpfkation m/e 158. Auffallend ausgepragt sind in Verbindungsklasse 3 antimykotische, trichomonazide und herbizide Wirksamkeit. By nucleophilic substitution of on…

Synthesis and Conformational Analysis of Saturated3,1,2-Benzoxazaphosphinine 2-Oxides

2005

N-Unsubstituted, N-methyl and N-benzyl cis- and trans-2(hydroxymethyl)cyclohexylamines were subjected to ring closure with phenylphosphonic dichloride, phenyl dichlorophosphate and bis(2-chloroethyl)phosphoramidic dichloride in order to synthesize P-epimeric diastereomers of the corresponding unsubsituted and N-substituted 2-phenyl-, 2phenoxy- and 2-[bis(2-chloroethyl)amino]octahydro-2H3,1,2-benzoxazaphosphinine 2-oxides. The stereochemistry and conformations of the prepared compounds were analyzed mainly by variable-temperature 1 H, 13 C and 31 P NMR spectroscopy. Geometry optimizations were performed for some trans-fused molecules by utilizing the B3LYP DFT method and a locally dense basi…

A macrocyclic diurea derived from diphenylether

2010

Abstract A new 16-membered cyclic diurea was synthesized and tested as potential receptor for fluoride. 1 H and 19 F NMR spectroscopy revealed an unexpected deprotonation of both urea groups after initial 1:1 binding. A single crystal X-ray structure shows bifurcated hydrogen bonds to two DMSO molecules.