Molecular strands incorporating three hydrogen bond donor (D) or acceptor (A) heterocycles form highly stable double helical complexes through a complementary AAA-DDD array structure.

The bisphosphine-catalyzed double-Michael addition of dinucleophiles to electron-deficient acetylenes is an efficient process for the synthesis of many nitrogen-containing heterocycles. Because the resulting heterocycles contain at least one stereogenic center, this double-Michael reaction would be even more useful if an asymmetric variant of the reaction were to be developed. Aminophosphines c...

The current study reports design and diversity oriented synthesis of novel heterocycles incorporating of thioureido linkage on position no C-4 which not yet been explored and could find new applications in biology. Employing reagent based skeletal diversity approach; a facile synthesis of heterocycles with thioureido linkage at C-4 position of the quinazoline moiety has been accomplished. All t...

A tandem gold-catalyzed cycloisomerization/Suzuki cross coupling sequence involving arylethynyl-N-methyliminodiacetic acid boronates is described. Combining the mildness of homogeneous gold catalysis with the versatility of N-methyliminodiacetic acid (MIDA) boronates, this tandem two-step method enables the rapid assembly of various aryl-substituted heterocycles without having to isolate or pur...

The addition of ynamides to acyl chlorides and N-heterocycles activated in situ with ethyl chloroformate has been accomplished at room temperature using copper iodide as catalyst. This economical and practical carbon-carbon bond formation provides convenient access to a variety of 3-aminoynones from aliphatic and aromatic acyl chlorides in up to 99% yield. The addition to pyridines and quinolin...

The aim of this work was to synthesize steroidal heterocycles and to elucidate the potential role of these compounds as antimicrobial agents. The synthesis of steroidal heterocycles containing the pyrazole, isoxazole, thiazole, pyrane, pyridine, pyridazine, or benzopyrane ring attached to the pregnene nucleus is reported. Progesterone (1) reacts with dimethyl formamide dimethyl acetal to form e...

Elucidation of mechanisms and discovery of novel reactions are interconnected, as four research chapters from the Munich laboratory demonstrate. 1) In a new opening of the furan ring, 2-methoxyfuran and tetra-acceptor-substituted ethylenes furnish methyl acrylates, which are cis-3-substituted by a cyclopropyl ring that bears the four acceptor groups. Experiments with trans- and cis-1,2-bis(trif...

Owing to their various modes of reactivity, aaminonitriles represent versatile building blocks for the construction of a wide range of nitrogen heterocycles. The present Concept article focuses on synthetic methodologies using their bifunctional nature which is the basis of their reactivity as a-amino carbanions and as iminium ions. Reactions exclusively taking place on either the amine or on t...

A three-step procedure for the synthesis of multifunctionalized heterocycles from a pyroglutamic acid derivative, glycidyl components and anilines by nucleophilic substitution and cobalt catalysis is presented.

The photoelectron (PE) spectra of l-(4-pyrimidyl)-2-(3-pyridyl)-ethene 1, l-(2-pyrimidyl)-2(3-pyridyl)-ethene 2, l-(4-pyridazinyl)-2-(3-pyridyl)-ethene 3, l-(3-pyridazinyl)-2-(3-pyridyl)ethene 4 and l-(2-pyrazinyl)-2-(3-pyridyl)-ethene 5 all in their trans conformations have been recorded using Hel radiation. Comparisons with the PE spectra of styrylpvridines, dipyridylethenes and diazabenzenes...