Preparation of halo enol phostones by reaction of acetylenic phosphonate monoesters with (bis-collidine)halo hexafluorophosphate

Reaction of non-conjugated acetylenic phosphonate monoesters with (bis-collidine) bromo and iodo hexafluorophosphates was found to lead to the formation of halo enol phostones. Depending on the size of the heterocyclic compounds formed (6-8-membered compounds), endo or a mixture of endo and exo cyclization products were obtained.     

Determination of heterocyclic aromatic amines (HAA) in commercially available meat products and fish by high performance liquid chromatography—Electrospray tandem mass spectrometry (HPLC-ESI-MS-MS)

Summary Ten heterocyclic aromatic amines (HAA) (1)–(10) were analyzed in commercially available meat products and fish. After sample preparation by Extrelut treatment and subsequent solid phase extraction applying propylsulphonic and C₁₈ silica cartridges, HPLC-ESI-MS-MS using selected reaction monitoring (SRM) and d₃-PhIP and d₃-MeIQx as internal and external standards, respectively, revealed the widely distributed presence of PhIP (8) and MeIQx (4), ranging from 0.1 to 5.3 ng g⁻¹ and 0.1 to 5.2 ng g⁻¹, respectively. Lower amounts were found for 4,8-DiMeIQx (5) and 7,8-DiMeIQx (6), ranging from 0.2 to 2.0 ng g⁻¹ and 0.1 to 0.2 ng g⁻¹, respectively. The other HAA under study, i.e. IQ, MeIQ, 4,7,8-TriMeIQx, Glu-P-1, and Glu-P-2 were not determinable under the experimental conditions used (determination limit 0.1 ng g⁻¹).     

氯化钇与水杨醛类杂环息夫碱配合物的合成与表征

由水杨醛制得的息夫碱及其配合物具有显著的抗癌活性［１］。近年来,过渡金属离子与此类配合物的研究已有文献报道［２］。为了研究钇与此类息夫碱的配位能力,我们在无水乙醇体系中合成了氯化钇与水杨醛类杂环息夫碱的三种新的固体配合物,并对其组成和配位方式进行了研...     

Concise and divergent total synthesis of swainsonine, 7-alkyl swainsonines, and 2,8a-diepilentiginosine via a chiral heterocyclic enaminoester intermediate

The concise and divergent total syntheses of (−)-swainsonine, (−)-7-alkyl swainsonines, and (−)-2,8a-diepilentiginosine from a common chiral heterocyclic enaminoester intermediate in five-step sequences are presented. The highly efficient annulation reaction of the chiral heterocyclic enaminoester with various α,β-unsaturated carboxylates, and a straightforward carboxy inversion constituted the key features of the synthetic pathway. This work provides an example for divergent synthesis of different natural and unnatural polyhydroxylated indolizidines from a readily available platform.     

SYNTHESIS AND CHARACTERIZATION OF POLY(ARYL ETHER KETONE)FROM 4-(3-PHENYL-4-HYDROXYPHENYL)PHTHALAZINONE

A novel soluble poly(aryl ether ketone) was prepared by the reaction of 4-(3-phenyl-4-hydr-oxyphenyl)phthalazinone with 4,4'-difluorobenzophenone. The polymer was characterized by DSC, TGA andX-ray diffraction.     

Preparation of a Series of 5-Methyl-3-(substituted)-[1,2,4]triazines

Procedures for the synthesis of thirty-six 5-methyl-3-(substituted)-[1,2,4]triazines have been described. These compounds were evaluated for antagonism at metabotropic glutamate receptor subtype 5 (mGluR5). Two compounds, 5b and 3c, were determined to be low micromolar inhibitors of mGluR5.     

Influence of bromoalkyloxy side chain on mesomorphic behavior in heterocyclic 7-(4-bromoalkyloxy)-3-(4′-decyloxyphenyl)-4H- 1-benzopyran-4-ones

A new homologous series of isoflavone-based ethers,7-(4-bromoalkyloxy)-3-(4’-decyloxyprienyl)-4H-1-benzopyran-4-ones were synthesized and characterized.The mesomorphic properties of all homologues were investigated by differential scanning calorimetry(DSC) and polarizing optical microscopy(POM).Enantiotropic smectic A(SmA) phase was observed for all homologues.The structure-property study was carried out by comparing the mesomorphic behavior of the homologues with those previously reported analogues.The bromine atom from the alkyloxy side chain of the benzene ring fused to the heterocyclic moiety was found to be capable of changing the mesomorphic properties.     

Highly efficient N‐Heterocyclic carbene–palladium complex‐catalyzed multicomponent carbonylative Suzuki reaction: novel practical synthesis of unsymmetric aryl ketones

Highly efficient and chemoselective N‐heterocyclic carbene palladium complexes‐catalyzed multicomponent carbonyltive Suzuki reaction with sodium tetraphenylborate used as phenylating reagent has been demonstrated in this article. Both electron‐rich and electron‐deficient aryl iodides gave unsymmetric aryl ketones in excellent yields. Copyright © 2007 John Wiley & Sons, Ltd.     

Approaches to Total Synthesis of Heterocyclic Steroidal Systems

In heterocyclic steroids the carbon atoms of the steroid skeleton (positions I to 17) are replaced in part by hetero atoms. The term generally denotes compounds containing one or two nitrogen, oxygen, and/or sulfur atoms. The part of the molecule containing the hetero atom is either introduced as a preformed unit or is constructed by stepwise synthesis. The examples given in the present article contain the hetero atoms in ring A, ring B, between rings A and B, and/or between rings C and D.     

Fluordiazadiphosphetidine, 11. Mitt.: Eine neue Methode zur Herstellung der doppelt zwitterionischen Verbindung (CH3N)6P4F8

A new synthetic route for the preparation of the betain-like compound (CH₃N)₆P₄F₈ from (CH₃NPF₃)₂,N-methyl-hexamethyldisilazane andN,N-dimethyl-urea has been found. The steps of this multi-stage reaction could be rationalized to a far extent.

10. Mitteilung:Kubjacek M., Utvary K., Mh. Chem.112, 305 (1981).