The mechanism of formation of coumarin (1) by Perkin reaction from salicylaldehyde was shown to involve exclusively a basecatalyzed intramolecular aldol-type condensation of O-acetyl salicylaldehyde (2) as an obligatory intermediate followed by dehydration. Direct evidence in support of this contention was provided by the formation of coumarin and 3-phenyl coumarin(5) as the sole products in th...

The kinetic rate equation for the photosensitized cleavage reaction of surface-bound photolabile chromophores with free diffusion of sensitizer molecules from the bulk of a solution to the surface is derived by determining the stationary solution of a diffusion equation with suitable boundary conditions. The relation between the phenomenological rate constant for the photosensitized reaction at...

We have developed an efficient route for the synthesis of the perhydroquinoline core of the indole alkaloid aspidophytine (2), starting from commercially available and inexpensive 3-acetylpyridine. This densely functionalized perhydroquinoline core displays four contiguous stereocenters including an all-carbon quaternary center. The synthetic sequence features a highly effective Diels-Alder rea...

Michael addition–halogenation–intramolecular ring-closing (MHIRC) reactions are processes in which a halogen atom as leaving group can attach to substrates or reactants during the reaction, then undergoes intramolecular ring closure. In this communication MHIRC transformation of 4-benzylidene-3-phenylisoxazol-5(4H)-one and 1,3-dimethylbarbituric acid presence N-bromosuccinimide sodium acetate E...

Abstract In this paper, the synthesis of carbon skeleton cotylenin A aglycone is described. The key reactions, including an intramolecular aldol reaction, coupling and a ring-closing meta­thesis, allow for effective stereoselective access to aglycone. stereochemistry was confirmed by single-crystal X-ray crystallographic analyses related compounds.

Photophysical and photochemical dynamics of ground state and excited state proton transfer reaction is reported for Pyrrole 2-Caboxyldehyde (PCL). Steady state absorption and emission measurements are conducted in this five member heterocyclic system (PCL). The theoretical investigation is done by using different quantum mechanical methods (e.g. Hartree Fock, DFT, MP2, CCSD etc.). The reaction ...

A subtractive implementation of the QM/QM hybrid method for the description of photochemical reactions occurring in molecular crystals is presented and tested by applying it in a simulation study of the ultrafast intramolecular excited-state proton transfer reaction in the crystal form of 7-(2-pyridyl)-indole, an organic compound featuring an intramolecular hydrogen bond within a six-membered r...

We have developed an efficient procedure for the easy and straightforward preparation of functionalized dihydropyridazines as highly enantiopure materials by reaction of pyruvaldehyde 2-tosyl hydrazone with a variety of α,β-unsaturated aldehydes using a chiral secondary amine as catalyst. The overall process consists of a cascade reaction involving an initial aza-Michael reaction, in which the ...