A concise and flexible approach for the asymmetric syntheses of polyhydroxylated pyrrolizidine alkaloids hyacinthacines A(2) and A(3) has been developed using iterative reductive alkylation of O,O'-dibenzyltartarimide (5) as key steps. The ambiguity about the structure of synthetic hyacinthacine A(3) due to the differences in the NMR data of the synthetic material (2) and the natural product (h...

The first chapter focuses on the introduction of iodine m ediated carbocyclisations and their applications continue to present a stim ulating challenge in targetand diversityoriented syntheses. Literature overview of m ore than past two decades about this area of research has been highlighted by including key examples along with the ir m echanistic aspects. The second chapter discusses applicat...

THE TITLE COMPOUND [SYSTEMATIC NAME: (3S,3aS,10bR)-3-isopropyl-5a,8-dimethyl-2,3,4,5,5a,6,7,10,10a,10b-deca-hydro-endo-epidioxy-cyclo-hepta-[e]indene-3a(1H)-carboxylic acid], C(20)H(30)O(4), is a polymorphic form of a previously reported structure [Loyola et al. (1990 ▶). Tetra-hedron, 46, 5413-5420]. The newly found ortho-rhom-bic polymorph crystallizes in P2(1)2(1)2(1) with two mol-ecules in ...

An interesting rearrangement of arylvinylidenecyclopropanes having three substituents at the 1- and 2-positions of the corresponding cyclopropane catalyzed by Lewis acids to give 6aH-benzo[c]fluorine derivatives via a double intramolecular Friedel-Crafts reaction or to give an indene derivative via an intramolecular Friedel-Crafts reaction is described.

Pyrrolizidine alkaloids are naturally occurring genotoxic chemicals produced by a large number of plants. The high toxicity of many pyrrolizidine alkaloids has caused considerable loss of free-ranging livestock due to liver and pulmonary lesions. Chronic exposure of toxic pyrrolizidine alkaloids to laboratory animals induces cancer. This investigation studies the metabolic activation of retrors...

It is now widely-recognized that the view that herbal remedies have no adverse effects and/or toxicity is incorrect; some traditionally-used plants can present toxicity. The well-established popular use of Ageratum conyzoides has led to its inclusion in a category of medicinal crude drugs created by the Brazilian Health Surveillance Agency. Ageratum belongs to the Eupatorieae tribe, Asteraceae,...

M. Wink* Universität München, Pharmazeutische Biologie, Karlstraße 29, D-8000 München 2, Bundesrepublik Deutschland D. Schneider Max-Planck-Institut für Verhaltensphysiologie, D-8131 Seewiesen, Bundesrepublik Deutschland L. Wit te Technische Universität Braunschweig, Institut für Organische Chemie, Hagenring 30, D-3300 Braunschweig, Bundesrepublik Deutschland Z. Naturforsch. 43c, 737-741 (1988)...

We present a route to successfully tackle the two main limitations, low open circuit voltage (Voc) and limited short circuit-density (Jsc), of polymer solar cells (PSCs) based on poly(3-hexylthiophene) (P3HT) as an electron-donor. The indene-C60 bisadduct (ICBA) was selected as an electron acceptor to improve the open circuit voltage (Voc). The narrow band gap polymer poly[(4,8-bis-(2-ethylhexy...

In the title compound, C30H28N4O, the central pyrrolidine ring adopts an envelope conformation with the CH2 C atom as the flap. The quinoxaline and indene ring systems are planar, with r.m.s. deviations of 0.0165 and 0.0181 Å, respectively. The pyrrolidine ring mean plane forms dihedral angles of 88.84 (1) and 86.14 (1)° with the quinoxaline and indene ring systems, respectively. A weak intra-m...

Following an initial work on the isolation of a single geometric isomer from an indene-C70 bisadduct (IC70BA) mixture, we report the full fractionation and identification of the bisadduct species in the material. Eleven fractions of IC70BA isomers were separated by high-performance liquid chromatography. A number of fractions contained relatively pure isomer species and their configuration were...