Driven by the increased demand for chiral drugs in enantiomerically pure form following the release of new FDA´s marketing guidelines, the search for novel methods for EPC-syntheses is a major topic in contemporary organic synthesis [ 1 ]. In this context, the use of biocatalysts has found widespread application in preparative organic chemistry over the last decade [ 2 ]. From the two principles of biocatalytic reactions where chiral molecules are involved, i.e. (i) desymmetrization of meso- and prochiral compounds [ 3 , 4 ] and (ii) kinetic resolution of racemates [ 5 ], the latter is astonishingly dominant in number of applications (~1:4) [ 6 ], which is probably due to the fact that meso- and prochiral substrates are less easily synthesized than racemates. Despite its widespread application, kinetic resolution is impeded by several inherent disadvantages for practical applications, in particular on an industrial scale. After all, it should be kept in mind that an ideal resolution process should provide a single enantiomeric product in 100 % yield. The most obvious drawbacks are as follows: (i) The theoretical yield of each enantiomer can never exceed a limit of 50 %, (ii) separation of the formed product from the remaining substrate may be laborious, in particular for those cases, where simple extraction or distillation fails and chromatographic methods are required [ 7 ]. (iii) In the majority of processes, only one stereoisomer is desired and there is little or no use for the other. In some rare cases, the unwanted isomer may be used through a separate pathway in an enantio-convergent fashion, but this requires additional labour and a highly flexible synthetic strategy [ 8 ]. (iv) For kinetic reasons, the optical purity of substrate and/or product is depleted at the point, where separation of product and substrate is most desirable from a preparative standpoint - i.e. 50 % conversion

The use of an enantiomerically pure amino alcohol, coupled to a transfer hydrogenation process, in the asymmetric catalysis of the reduction of ketones to alcohols, is described. The process works well for unfunctionalised ketones, affording e.e.s of up to 98%, and excellent conversions. We have recently extended, for the first time in this application, the scope of the methodology to the reductions of a-heteroatom substituted substrates, through the use of the appropriate protecting groups on each atom.

1-Aryl-pyrazolo[4,3-c]quinolin-3-ones 1 reveal interesting structures because of their potential biological activity [1]. A binding study on bovine brain membranes has shown that 1-aryl- pyrazolo[4,3-c]quinolin-3-ones 1 bearing different substituents at position 4 possess activity in displacing specific [3H]flunitrazepam from its receptor site [2]. In this paper we present new strategies for the synthesis of 1-aryl- or 2-arylamino-pyrazolo[4,3-c]fused heterocycles such as 1-aryl-pyrazolo[4,3-c]fused quinolines and coumarins having hydrogen-, methyl- or aryl-substituents at position 3. The cyclization conditions were studied by differential scanning calorimetry (DSC).

Wittig rearrangements have been studied for a long time, the [2,3]-rearrangement being the most widely studied, and there are many reports on its mechanistic and synthetic applications {1}. The corresponding [1,2]-rearrangement has been studied too, but has not been so widely used as a synthetic tool, remaining mainly as a competitive reaction that interferes with the other possible rearrangements.

Recently there has been an increasing interest in the chemistry of nucleophilic additions to styrene and its derivatives {1-6}. Although there were some early reports on the addition of nucleophiles to styrene without leading to polymerization, the synthetic application of this reaction was not exploited until our group started new studies on its chemistry{1}. Now that the synthetic viability of these additions has been established, it is of great interest to study the scope of the reaction. Here we present our studies on the addition of alkyllithiums to 2-vinylbenzoic acid (1). In an earlier report {4} of the reaction of 1 with BuLi, the expected product was obtained only in a 19% yield. As the authors did not mention any reason for the low yield we decided to study this addition to see if there was any incompatibility between the carboxylic acid group and the alkyllithium. There could be a competition between the reaction of addition to carboxylate to give a ketone and the addition to the exocyclic double bond.

The synthesis and photosynthesis-inhibiting activity of 14 new 3-(2-alkylsulfanyl-6- benzothiazolylaminomethyl)-2-benzoxazolethiones are reported. The new compounds were prepared by the reaction of 2-alkylsulfanyl-6-aminobenzothiazoles with 3-hydroxymethyl-2-benzoxazolethione. The structures of the compounds were verified by 1H NMR spectra. The compounds inhibit photosynthetic electron transport in spinach chloroplasts. The photosynthetic activity was found to depend on the calculated lipophilicity of the new compounds. Some structure characteristics and quantum chemical parameters were calculated by AM1 method

Enantiomerically pure aziridine-2-carboxylates containing a CH2OMs group, and azetidine-3-mesyloxy-2- carboxylates were prepared by cyclization of 2-amino-3,4-dimesyloxybutyrates, stereoselectiveprepared from aspartic acid. The outcome of the cyclization was dictated by the configuration of the C-3 stereogenic center. The mesylate group of the aziridino mesylates could be displaced by nucleophiles without opening of the aziridine ring.

The Heck reaction is efficiently and rapidly obtained by a palladium-catalysed reaction in water performed in a Teflon autoclave under microwave irradiation with a commercial microwave oven. Water soluble phosphine-ligand catalysts and phase transfer catalysis conditions are used.

The title compounds were synthesised by furan alkylation with various 2- hydroxybenzyl alkohols. Route to various derivatives of 3-R-2-(3- oxobutyl)benzo[b]furan was shown. The synthesis of dibenzoxazulenium derivatives was attempted.

A new chemoselective approach to synthesis of a series of 3-substituted coumarin derivatives and 6- substituted benzo[4,5]imidazo[1,2-a]quinolines was developed. It was based on novel rearrangements of different 3-substituted 2-imino-2H-1-benzopyrans 1 (2-imino-2H-1-benzopyran-3-carboxamide and 2-imino-3-(1Hbenzoimidazol- 2-yl)-2H-1-benzopyran) under action of N-nucleophiles. By using this methodology, two series of heterocyclic systems were synthesized, namely: i) containing coumarin (2-oxo-2H-1-benzopyran) moiety substituted at C-3 position with different heterocycles such as 4H-1,2,4-triazole (7 and 10), 1,3,4-oxadiazole (8), 1,3,4-thiadiazole (9), 5-oxo-1,4- dihydro-benzo[e][1,2,4]triazepine (12), 1,1-dioxo-2H-benzo[e][1,2,4]thiadiazine (13), 4-oxo-3H-quinazoline (17), 4-oxo-5,6,7,8-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidine (19), 1H-benzoimidazole (20), benzooxazole (21), benzothiazole (22), and ii) comprising benzo[4,5]imidazo[1,2-a]quinoline backbone substituted at C-6 position with 1Hbenzoimidazole (23) and benzooxazole (24) units. Possible mechanisms of the revealed rearrangements were discussed and this approach is considered to be a new and efficient alternative route to a variety of heterocyclic compounds.