Reactions of Phosphorodiamidous Acid Esters with α-Halocarbonyl Compounds

Reactions of ethyl and tert-butyl phosphorodiamidites with chloroacetone, bromoacetone, and -chloroethyl acetate were studied. The reaction pathway is determined by the structure of the intermediate quasiphosphonium compound responsible for the formation of the Arbuzov product as well as for the occurrence of the amonalous reaction yielding vinyl phosphate.     

Glucomannan from Narcissus poeticus Studied by PMR and 13C NMR Spectroscopy

Native acetylated glucomannan of molecular weight (MW) 32000 with a glucose:mannose ratio 1:30 was isolated from bulbs of Narcissus poeticus. Glucomannan was depolymerized to a fragment of MW 15000 with an unchanged primary structure and was studied using PMR and ¹³C NMR spectroscopy. It was found that the linear chain of the biopolymer consists of 1-4-bound D-gluco- and D-mannopyranose units and the O-Ac groups are localized on C-2, C-3, and C-6 hydroxyls in certain anhydromannose units.     

Structure and properties of 2,4a-dimethyl-4-phenyl-3-ethoxycarbonyl-5-oxo-4a,5-dihydro-4H-indeno[1,2-b]pyridine

The molecular and crystal structure of 2,3a-dimethyl-4-phenyl-3-ethoxycarbony-5-oxo-4a,5-dihydro-4H-indeno[1,2-b]pyridine has been determined, and its reduction and alkaline and acid hydrolysis reactions have been studied.Translated from Khimiya Geterotsiklicheskikh Soedineii, No. 10, pp. 1388–1392, October, 1984.     

Phytoecdysteroids of plants of the genusSilene XIV. Brahuisterone fromSilene brahuica

A new ecdysteroid with the composition C₂₇H₄₄O₆ which has been called brahuisterone has been isolated from the epigeal part of the plantSilene brahuica Boiss. Its chemical and complete spatial structures have been established by spectral studies and the x-ray structural method (diffractometer, Cu-K radiations, 996 reflections, direct method, R=0.119).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbekistan Republic, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 553–558, July–August, 1993.     

Organophosphorus derivatives of pentachlorobenzenethiol

Conclusions Nine new organophosphorus derivatives of pentachlorobenzenethiol were synthesized by the reactions of pentachlorobenzenesulfenvl chloride with dialkyl hydrogen phosphites and O,O-dialkyl hydrogen phosphorothioites.