Recently, we have reported [1] the microwave enhanced synthesis of 4-aminoquinazolines from anthranilonitrile and several aromatic nitriles Scheme 1. In the absence of another nitrile, anthranilonitrile dimerized to gave the corresponding 4-amino-2-(2'-aminophenyl)quinazoline. There we reported a reduction in reaction times together with an improvement in yields regarding to the methods using conventional heating.

Benzonorbornadiene 21, 7-spirocyclopropylbenzonorbornadiene 23, 7,7-dimethylbenzonorbornadiene 25 , and 7-spirocyclopentylbenzonorbornadiene 27 have been reacted with 3,6-di(2-pyridyl)-s-tetrazine (21>23>25=27) to form symmetrical 4,5-hydropyridazines which are stable towards fragmentation but rearrange with varying facility to their 1,4 isomers. The facial selectivity of attack on the p-bond changes from exo-attack for 21 and 23 to endo-attack for 25 and 27. The 7-spirocyclopropylbenzonorbornadiene 23 typically forms a mixture of dihydropyridazines with exo-stereochemistry, which undergo further stereochemical isomerisation to an exo-fused product upon acetylation (acetyl chloride in hot pyridine). Oxidation with DDQ of these dihydro compounds individually or as mixtures gives the corresponding fused 3,6-dipyridylpyridazines

A new convenient method for the synthesis of hydrogenated 2-cyaniminopyrimidines has been developed. This method is based on preparation of a-tosyl substituted N-cyanoguanidines 11 followed by reaction with enolates of a-functionally substituted ketones to give 5-functionalized 2-cyanimino-4-hydroxypyrimidines 12, 13, 15, 16. All the obtained hydroxypyrimidines are readily converted into the corresponding 5-functionalized 2-cyanimino-1,2,3,4-tetrahydrohydropyrimidines 17-20 by heating in the presence of acids. Treatment of 5-acetyl-4-hydroxypyrimidines 12 with aq. KOH gives 4-hydroxypyrimidines 21 in result of removing the acetyl group

2,4-Di(hetero)aryl substituted 2,3-dihydro 1,5-benzodiazepines, -oxazepines, and thiazepines can be readily synthesized in a three component one-pot process initiated by a coupling-isomerization sequence of an electron poor (hetero)aryl halide and a terminal propargyl alcohol subsequently followed by a cyclocondensation with 2-amino, 2-hydroxy, or 2-mercapto anilines.

Alkynylated and butadiynyl bridged phenothiazines with variable functionalization can be synthesized in good yields by cross-coupling and condensation approaches. These oligofunctional heterocycles represent suitable building blocks for a novel type of redox addressable organic molecular wire.

The preparation, stability and behaviour of b,b,b-trichloro-tert.-butyl (Tcb) esters towards various conditions of deprotection were evaluated. Tcb esters can be prepared from the halide of the corresponding carboxylic acid and b,b,b-trichloro-tert.-butanol in the presence of anhydrous zinc chloride. They are stable in acidic and basic medium and can be cleaved under mild conditions (e.g. with zinc, cadmium or indium under slightly acidic or neutral pH, with the supernucleophile cobalt(I) phthalocyanine, Table 1). Provided that the requested acyl halides are easily available, the Tcb group can be efficiently used for the protection of carboxyl functionality.

Ferrocene behaves much like a three dimensional arene and is useful for incorporating a metal atom into a molecule that requires a certain degree of structural rigidity such as a liquid crystal.1 The ferrocenyl unit is not only useful for modifying the shape of a molecule; in addition the metal atom with its large electron density can be used to modify the physical properties such as colour, polarisability and magnetism. Following the publication in 1976 of the first examples of ferrocene derivatives with liquid-crystalline properties (type A) 2and more notably since 1988 when the first liquid crystals based on a disubstituted ferrocene were synthesized (type B),3 there has been a growing interest in these compounds amongst chemists. The majority of ferrocenyl-containing liquid crystals or ferrocenomesogens (as we have named them) prepared so far belong to one of the structural types A, B or C. Although the synthesis of derivatives with interesting new shapes continue to be exciting, a systematic approach to structure-liquid crystal activity which will allow meaningful predictions has become necessary.

A versatile synthesis of xylose derived d-aminoalkenes is presented. We have previously reported on the stereoselective synthesis of polyhydroxypiperidines.1 An extension to the methodology to incorporate more exotic Nsubstituted compounds was sought. This communication reports, in particular, the result of the completion of a synthetic sequence for the preparation of carbohydrate derived d-aminoalkenes.

The synthesis of reticulated polyelectrolytes possessing ion-exchange properties, remains a topical task in chemistry. The constant widening of the application fields of such polymers in experimental studies and industry stipulates a more and more increasing interest to the problem of their preparation.

Five-, six- and seven-membered silacycloalkenes have been prepared by carbon-carbon bond forming cyclisation of dienyl- and enynylsilanes under RCM conditions. The relative ease of ring formation from dienes was in the order six- >seven- > five-membered rings. A conjugated vinylsilacyclopentene was formed from a corresponding enyne substrate. Silaspirenes have been prepared from silacarbacycles by the same methodology