A simple highly versatile and efficient sonochemical synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles is achieved by condensation of 1,2-dicarbonyl compound, aldehyde, ammonium acetate and primary amine using antimony trichloride immobilized on silica gel (SiO2-OSbCl2) as a catalyst in ethanol at moderate temperature. Operational simplicity, practicability and applicabi...

1. Conditions were established for the reaction of retinal with phosphatidylethanolamine, phosphatidylserine, ethanolamine and serine in chloroform, ethanol or ethanol-water solutions to form retinylidene compounds, or Schiff bases. 2. The Schiff bases were reduced to retinyl compounds with sodium borohydride. 3. Absorption maxima and molar extinction coefficients were determined for the variou...

1. Vitamin A has been found in the retinas and the combined pigment epithelia and choroid layers of frogs, pigs, sheep, and cattle. The vitamin was identified by (a) its specific absorption at 328 mmicro; (b) the blue color yielded with antimony trichloride, associated with an absorption band at about 620 mmicro; (c) anti-xerophthalmic and growth-promoting activity; and (d) quantitative relatio...

Preamble It was a pleasure to be invited to act as editor for this themed issue in which we aim to assemble a series of invited and submitted papers which provide a look at some of the current research efforts defining the subject of “Chemical Crystallography”. Of course, the timing of this is to make a positive contribution to the celebration of this special year, 2014 the UNESCO Year of Cryst...

Since both carotene and vitamin A yield a blue color with SbCla, attempts to determine t,he vitamin quantitatively in a mixture depend, among other things (1, 2)) upon the accuracy with which the blue color due to carotene can be estimated. Values published for the blue equivalent of carotene range from 3.5 to 13, calculated as micrograms of apparent vitamin A per 100 y of carotene (3). This di...

1. Columns of Sephadex G-25 have been used for the preliminary fractionation of tryptic digests of casein. 2. Fractions from Sephadex columns have been examined for their ability to stimulate the growth of a strain of Streptococcus equi8imili8. Maximum stimulatory activity appeared to be localized in a fairly narrow region of the total peptide material. 3. Further fractionation of peptides deri...

A simple highly versatile and efficient sonochemical synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles is achieved by condensation of 1,2-dicarbonyl compound, aldehyde, ammonium acetate and primary amine using antimony trichloride immobilized on silica gel (SiO2-OSbCl2) as a catalyst in ethanol at moderate temperature. Operational simplicity, practicability and applicabi...

Carr and Price (1926) originally described a jnethod of determining the amount of vitamin A by the use of antimony trichloride. A quantity of the liver, or other organ, to be tested was dried and extracted in a Soxhlet apparatus, and j^test carried out with the extract. This is a tedious procedure when large numbers of tests ^re being done, and Moore (1930) modified it by dissolving the samples...