Abstract
Mechanisms of some organic solid state reactions were studied by monitoring these reactions with IR spectral measurements. Monitoring of a K2CO3-assisted Rap-Stoermer reaction of salicylaldehyde (1) and phenacyl bromide (4) showed that, firstly, a 1:1 complex (3) of the potassium salt of 1 (2) and 1 is formed, thereafter 3 is converted into 2. Secondly, the benzoylmethyl ether of 1 (5) produced by a substitution reaction of 2 with 4 gives the cis-dihydro-2-benzoylbenzofuran intermediate (6) which upon dehydration results in the final product, 2-benzoylbenzofuran (7). The intermediates, 2 and 6 were isolated as colorless crystals. The cis-structure of 6 was determined by X-ray analysis. However, structure of 3 was not clarified, since 3 did not form appropriate crystal for X-ray analysis. Benzoylation reaction of 1,2-dihydroxynaphthalene (8) with p-toluoyl chloride (9) was found to proceed via a 2:1 complex (10) of 8 and its dibenzoate (11). The complex 10 was isolated and its crystal structure was determined by X-ray analysis. By monitoring with IR spectral measurements, an imine derivative was detected as an intermediate of Thorpe reaction. As an intermediate of Na2CO3-assisted Knoevenagel reaction of 2-formylnaphthalene with malononitrile, an ionic intermediate derived from the reaction product, malononitrile and Na2CO3 was detected, although its structure was not elucidated yet.
