Heterocyclic compoundsDesai, R.; Mavani, C.
doi: 10.1007/BF03049160pmid: N/A
The condensation of gallic acid, pyrogallol carboxylic acid as well as their methyl and ethyl esters, gallacetophenone and 4-ethyl-pyrogallol with aceto-acetic ester, shows that all these groups exercise inhibitory effect in the Pechmann reaction to a varying extent. As β-resorcylic acid is reactive in such cases, it follows that the derivatives of pyrogallol are less reactive than those of resorcinol. The diacetyl derivatives of 7∶8-dihydroxy-coumarins do not undergo the Fries Migration.
The condensation of aldehydes with amidesIttyerah, P.; Pandya, Kantilal
doi: 10.1007/BF03049161pmid: N/A
o-Nitrobenzaldehyde has been condensed with seven different amides, by heating them together by themselves or with a trace of pyridine. Pyridine is found to be neither helpful nor harmful in these cases. The condensationproduct in every case has been of the benzylidenebisamide type. The yields were quite fair, ranging from 40 to 65%, and were nearly quantitative in the case of heptamide.
Heterocyclic compoundsDesai, R.; Mavani, C.
doi: 10.1007/BF03049162pmid: N/A
The condensation of β-ketonic esters with hydroquinone, quinacetophenone, 2-chloro-, 2-bromo-, 2-methyl-, and 2-ethylhydroquinones in presence of 73 per cent. sulphuric acid shows that the presence of acetyl and bromo groups exert inhibitory effect, while methyl and ethyl groups exert the accelerating effect on the Pechmann Reaction, when present in the hydroquinone molecule. The effect of chlorine group is to reduce the activity to a slight extent.
Chemical investigation of Indian lichensRao, V.; Seshadri, T.
doi: 10.1007/BF03049164pmid: N/A
The constitution of montagnetol has been established as the erythrityl ester of orsellinic acid for the following reasons: (1) it gives the homofluorescein reaction slowly, (2) 5-hydroxy-4: 7-dimethyl coumarin could be obtained as a product of its condensation with ethylacetoacetate under the conditions of Pechmann’s reaction, (3) decomposition with hot dilute sulphuric acid or with hot baryta produces orcinol and erythritol, (4) concentrated sulphuric acid at 0° gives orsellinic acid and erythritol, (5) hot methyl alcoholic potash coverts it into methyl orsellinate and erythritol, and (6) by the action of diazomethane followed by methyl acloholic potash dimethyl ether of methyl orsellinate is obtained.
Fluorescence, absorption and scattering of light in rubyMani, Anna
doi: 10.1007/BF03049167pmid: N/A
The paper deals with the results of a spectroscopic investigation of the fluorescence, absorption and scattering of light in ruby. The first order lattice spectrum of alumina is shown to possess eighteen normal modes of vibrations. Two Raman lines having frequency shifts of 376 and 412 cm.−1 have been obtained with a single crystal of alumina. The fluorescence and absorption spectra of ruby have been recorded using specially sensitized infra-red plates to register the bands in the long wavelength region with good intensity. The polarisation characters of the bands have also been studied with reference to the direction of the optic axis of the crystal and the direction of polarisation of the incident beam. From a perusal of the results, the emission bands have been divided into two groupsviz., (1) electronic bands caused by transitions of the shielded electrons of Cr+++ ion, (2) vibrational bands arising from a modulation of the electronic transitions by the crystal lattice vibrations. The frequency shifts of eight of the vibrational bands from the principal doublets agree fairly well with one or the other of the observed Raman and infra-red frequencies of alumina. The polarisation characters of the bands on the Stokes sides are also in good agreement with those of the corresponding bands on the anti-Stokes side.