Search results for "medicinal"
showing 10 items of 2966 documents
Heterocyclic rearrangements. Synthesis of 1,2,4-oxadiazolo[2,3-a]pyrimidinium systems and their ring opening into pyrimidineN-oxides
1986
Reaction des methyl- et phenyl-5 amino-3 oxadiazoles-1,2,4 avec l'acetylacetone ou la benzoylacetone en presence d'acide perchlorique: obtention de methyl- et phenyl-2 methyl- et phenyl-5 methyl-7 oxadiazolo [2,3-a] pyrimidiniums-4 qui se decyclisent ensuite en oxydes-1 d'acylamino-2- et amino-2 methyl-4 methyl- et phenyl-6 pyrimidines
Conjugated Compounds Based on Vinylthiazole Units
2007
Conjugated oligomers attract increasing attention because of their interesting properties in materials science [1]. Moreover, they are model compounds for conjugated polymers. Molecules polarized by electronic effects, in particular push-pull systems having terminal donor-acceptor substitution represent a special class of such oligomers [2]. Their major applications are in the field of nonlinear optics (NLO), twophoton absorption (TPA), two-photon induced fluorescence (TPIF), and photorefractive materials (PR). Fig. 1 illustrates known 2,5-thienylenevinylenes with zwitterionic resonance structures 1 (D = NR2; A = NO2, CHO, SO2R; n = 1, 2) [3, 4]. The corresponding compounds 2 with thiazole …
Über eine Reaktion vono-Hydroxybenzylalkoholen mit Estern von Säuren des Phosphors mit der Koordinationszahl 3
1978
Abstract o-Hydroxybenzyl alcohol reacts with trimethyl phosphite under smooth conditions to o-hydroxyphenylmethane phosphonic acid dimethyl ester. This unusual reaction is of widest applicability. Derivatives of o-hydroxybenzyl alcohol independent of type, number or position of substituents in the ring, react with alkyl esters of phosphorous, phosphonous or phosphinous acids in an analogous process, forming the corresponding o-hydroxyphenylmethane phosphonic or phosphinic esters or phosphine oxides.
Synthese und13C-NMR-Spektroskopie cyclischer und acyclischer β-Phosphonioenamine
1979
Quartare Phosphoniumsalze, die auser einem Allyl- einen Alkinylrest (z. B. 1) oder einen Acylmethylrest tragen (z. B. 4–6) reagieren mit primaren Aminen zu den bisher unbekannten 1,2,3,4-Tetrahydro-1,4-azaphosphoriniumsalzen 2, 3, 8–12, 19 und 25. Die Umsetzung von 4 liefert in Abhangigkeit vom eingesetzten Amin auser 8–12 die 5-Amino-1,2,3,4-tetrahydro-3-methylphosphoriniumsalze 13–16 die im sauren Medium schnell zu 17 hydrolysieren. Als Zwischenstufen der Cyclisierung von 4 konnen die offenkettigen β-Phosphonioenamine 18, 20 und 21 isoliert werden. Die Cyclisierung von 18 zu 19 gelingt erst in Gegenwart von Triethylamin als Base. Struktur und Konfiguration der neuen Verbindungen werden mi…
Coordination complexes of chromium(0) with a series of 1,3-diphenyl-6-arylfulvenes
2018
The synthesis and structural properties of a series of chromium tricarbonyl `piano-stool' complexes bearing substituted pentafulvene ligands were studied. The complexes, tricarbonyl(1,3,6-triphenylfulvene)chromium(0) benzene hemisolvate, [Cr(C24H18)(CO)3]·0.5C6H6 (I), tricarbonyl[1,3-diphenyl-6-(3-vinylphenyl)fulvene]chromium(0), [Cr(C26H20)(CO)3] (II), and tricarbonyl[1,3-diphenyl-6-(pyren-1-yl)fulvene]chromium(0), [Cr(C34H22)(CO)3] (III), each have a distorted octahedral geometry, with the fulvene coordinated in a π–η2:π–η2:π–η2 fashion. Significant deviation of the exocyclic fulvene double bond from the cyclopentadiene plane accompanies coordination. Evidence of non-covalent π–π interact…
Crystal structure of diethyl (E)-2-[(benzofuran-2-yl)methylidene]succinate
2015
The title compound, C17H18O5, was synthesized by a base-free catalytic Wittig reaction. The molecule consists of a diethyl itaconate unit, which is connectedviathe C=C double bond to a benzofuran moiety. The benzofuran ring system (r.m.s. deviation = 0.007 Å) forms dihedral angles of 79.58 (4) and 12.12 (10)° with the mean planes through thecisandtransethoxycarbonyl groups, respectively. An intramolecular C—H...O hydrogen bond involving the O atom of the benzofuran moiety is observed. In the crystal, molecules are linked into ribbons running parallel to thebaxis by C—H...O hydrogen bonds.
Crystal structure of (E)-4-methoxy-2-{[(5-methylpyridin-2-yl)imino]methyl}phenol
2015
The molecule of the title Schiff base compound, C14H14N2O2, displays anEconformation with respect the imine C=N double bond. The molecule is approximately planar, with the dihedral angle formed by the planes of the pyridine and benzene rings being 5.72 (6)°. There is an intramolecular hydrogen bond involving the phenolic H and imine N atoms.
Crystal structure of 2-methyl-1H-imidazol-3-ium aquatrichlorido(oxalato-κ2O,O′)stannate(IV)
2015
N—H⋯O, N—H⋯Cl and O—H⋯O hydrogen bonds between cations and anions in the complex salt (C4H7N2)+[Sn(H2O)Cl3(C2O4)]− are responsible for the formation of a three-dimensional network structure.
Crystal structure of 1-hydroxy-2,2,6,6-tetramethylpiperidin-1-ium trifluoromethanesulfonate
2015
In the cation of the title salt, C9H20NO+·CF3O3S−, the six-membered heterocyclic ring displays a chair conformation. In the crystal, centrosymmetric pairs of cations and anions are linked by N—H...O and O—H...O hydrogen bonds to form rings with aR44(14) graph-set motif.
Organocatalytic enantioselective synthesis of trifluoromethyl-containing tetralin derivatives by sequential (hetero)Michael reaction–intramolecular n…
2017
The enantioselective synthesis of tetralin derivatives bearing a trifluoromethylated all‐carbon quaternary stereocenter has been accomplished through a synthetic sequence comprising an organocatalytic β‐functionalization of ortho‐1‐trifluoromethylvinyl‐(hetero)aromatic conjugated aldehydes followed by the intramolecular nitrone 1,3‐cycloaddition reaction (INCR). Both nitromethane and N‐Cbz‐hydroxylamine were employed as nucleophiles in the initial organocatalytic conjugate addition step, which provided the chiral information required for the subsequent diastereoselective INCR. Although diastereoselectivity was moderate, good yields and enantioselectivities were, in general, obtained. Intere…