Hantzsch esters (1,4-dihydropyridine dicarboxylates) have become, in this century, very versatile reagents for enantioselective organic transformations. They can act as hydride transfer agents to reduce, regioselectively, a variety of multiple bonds, e.g., C=C and C=N, under mild reaction conditions. are excellent the dearomatization heteroaromatic substances, participate readily cascade proces...

by four technologists), the coefficient of variation was 5.5% (93.6 mg/dl ± 5.0 SD). We have used the method successfully, without technical difficulties. The advantages: the method is colorimetnc and requires no special equipment; although manual, it is rapid, and 30 to 40 specimens can be processed in 3 h; it is reproducible and the results compare well to those obtained by other Hantzsch con...

The catalytic ability of ZrO(2)/SO(4)(2-) to promote solventless three-component condensation reactions of a diversity of aromatic aldehydes, urea or thoiurea and ethyl acetoacetate was studied. Products resulting from Hantzsch and/or Biginelli multi-component reactions are obtained in the presence of solid acid catalysts using the same reactants but different temperature conditions. The sulfat...

Allylation and benzylation of p-quinones was achieved through an unusual redox chain reaction. Mechanistic studies suggest that the existence of trace hydroquinone initiates a redox chain reaction that consists of a Lewis acid catalyzed Friedel-Crafts alkylation and a subsequent redox equilibrium that regenerates hydroquinone. The electrophiles could be various allylic and benzylic esters. The ...

Dynamic kinetic Transfer hydrogenation reaction of 2-methyl-2,4-diaryl-2,3-dihydrobenzo[b][1,4]diazepines, using phosphoric acids as catalysts and Hantzsch ester as hydride source, has been studied. A 3,3'-H8-binol derived phosphoric acid has been identified the optimal chiral catalyst for this transformation, affording 1,3-diamine derivatives with up to 8/1 dr, 86% ee and 94% ee for the major ...

1,4 dihydropyridines (e.g. nifedipine) undoubtedly are among the most powerful calcium antagonists. They act by blocking Ca channels when bound from the outside of the sarcolemma on a proteinic receptor (Glossmann et al. 1982). From inotropic measurements it had been supposed that a new dihydropyridine compound (BAY-K 8644, Methyl