Proceedings of the Indian Academy of Sciences - Section A

Kartha, Gopinath

doi: 10.1007/BF03045229pmid: N/A

The crystal structure of barium bromate monohydrate has been determined and the atomic co-ordinates refined by differential synthesis and minimization methods as well as by Fourier methods. It is found that the atomic arrangement is closely similar to that in barium chlorate monohydrate.

Rangaswami, S.; Rama Sastry, B.

doi: 10.1007/BF03045230pmid: N/A

The results obtained by a more detailed study of some of the amorphous fractions described in the previous communication on the root bark ofTephrosia lanceolata are herein recorded. Treatment of the amorphous residues after separation of Substance I (renamed Lanceolatin A), Substance II and Substance III (renamed Lanceolatin B) with methanolic potassium hydroxide has enabled the isolation of another crystalline substance, now named Lanceolatin C and further quantities of Lanceolatin B. Lanceolatin C is biologically inactive (fish test). The alkali-soluble portion of the chloroform extract of the root bark was also found to contain a small amount of Lanceolatin C. Several other active and inactive amorphous fractions are also described.

Krishna Rao, J.

doi: 10.1007/BF03045231pmid: N/A

1. Manganese garnets of Vizagapatam District called by Fermor “Spandites” are metamorphic in origin and are mixtures of the garnet molecules—spessartite, calderite, almandite and andradite.

Sunthankar, A.; Tilak, B.; Venkataraman, K.

doi: 10.1007/BF03045232pmid: N/A

p-Nitrophenyl bromomethyl sulphone (II) andp-nitrophenyl phthalimidomethyl sulphone (X) were prepared with the view to synthesize the sulphone analogue (I) of chloramphenicol. In contrast with the synthesis of chloramphenicol from analogous phenacyl derivatives, (II) and (X) could not be converted to (I) on account of the deactivating influence of the sulphone group in aryl methyl sulphones.

Naik, R.; Mehta, A.; Thakor, V.; Jadhav, G.; Shah, R.

doi: 10.1007/BF03045233pmid: N/A

Ramanathan, V.; Venkataraman, K.

doi: 10.1007/BF03045234pmid: N/A

A general method for the preparation of 5-hydroxyflavone and its derivatives from the corresponding 5:7-dihydroxyflavones by the action of Raney nickel on the 7-tosyloxy derivatives is described. Thus chrysin has been converted into 5-hydroxyflavone, and galangin 3-methyl ether to 5-hydroxy-3-methoxyflavone.

Ganapathi, K.; Kulkarni, K.

doi: 10.1007/BF03045235pmid: N/A

Ganapathi, K.; Kulkarni, K.

doi: 10.1007/BF03045236pmid: N/A

Chrysean has been isolated in two forms; whether they are stereosoimers or only dimorphic forms is discussed. A mechanism of formation of chrysean is suggested. With methyl iodide it gives readily the S-methyl derivative which reacts easily with aniline,p-chloraniline andm-aminophenol to furnish the amidino derivatives of formula (IX). Chrysean on being refluxed with ethyl acetoacetate in alcohol gave the acrylidene derivative (X) which cyclises on heating to the pyridinothiazole derivative (XI). Ethyl acetoacetate and chrysean at higher temperature condensed to yield the acetoacetyl derivative (XIII) which however did not cyclise to furnish (XIV).

Popov, B.

doi: 10.1007/BF03045237pmid: N/A

Bhat, M.

doi: 10.1007/BF03045238pmid: N/A

Studies of the spectral character of the light transmitted by Christiansen filters in various circumstances have been carried out and are discussed in the light of wave-optical theory. The results are illustrated by a series of spectrograms reproduced with the paper. When the dispersive powers of the solid powder and of the liquid in which it is immersed are nearly equal, the transmission extends over a wide range of the spectrum.Per contra, it narrows down with increasing difference in the dispersive powers. The influence of the same factor is also strikingly evident when the wave-length of maximum transmission is shifted towards shorter wave-lengths by changing the composition of the liquid. A pronounced asymmetry is also noticeable in the spectral distribution of intensity of the transmitted light. The size of the particles of the powder and the total thickness of the filter are other factors which influence the spectral range of transmission. Of particular interest are the results obtained when the powder is only loosely suspended in the liquid and not tightly packed.