13C NMR spectra of biologically active compounds. II. 11-Deoxy-16- and 17-aryloxyprostaglandins

The¹³C NMR spectra of the initial ω-aryloxy chains and the final 16-and 17-aryloxyprostaglandins of the 11-deoxy series have been investigated, and stereochemical assignments have been made for the diastereomeric pairs. A weakening of the diastereotopic effects in the spectra of the 15- and 16-methyl-substituted 16- and 17-phenoxypropstaglandins to 0.1 ppm has been shown.     

A green synthesis in water of novel (1,5,3-dithiazepan-3-yl)alkanoic acids by the multicomponent reaction of amino acids, $$\hbox {CH}_{2}$$O,and 1,2-ethanedithiol

A library of new (1,5,3-dithiazepan-3-yl)alkanoic acids was prepared by the multicomponent cyclocondensation of amino acids, formaldehyde, and 1,2-ethanedithiol in water at room temperature for 1 to 5 h in high yields. This green procedure offers several advantages such as an operational simplicity, no catalyst, and no production of hazardous materials.     

Catalytic [6<Emphasis Type="Italic">π</Emphasis> + 2<Emphasis Type="Italic">π</Emphasis>]-Cycloaddition of 1,2-Dienes to Bis(cyclohepta-1,3,5-trien-7-yl)alkanes in the Presence of Ti(acac)<Subscript>2</Subscript>Cl<Subscript>2</Subscript>,–Et<Subscript>2</Subscript>AlCl

An efficient procedure has been developed for the synthesis of difficultly accessible 9,9′-(alkane-α,ω-diyl)bis[7-(diphenylmethylidene)bicyclo[4.2.1]nona-2,4-dienes] and 16,16′-(alkane-α,ω-diyl)bis(tricyclo-[9.4.1.0^2,10]hexa-2,12,14-trienes) in 55–84% yields by [6π + 2π]-cycloaddition of 7,7′-(alkane-α,ω-diyl)bis-(cyclohepta-1,3,5-trienes) to 1,1-diphenylpropa-1,2-diene and cyclonona-1,2-diene in the presence of the catalytic system Ti(acac)₂Cl₂–Et₂AlCl. The structure of the isolated compounds has been reliably proved by modern spectral methods.     

13C NMR spectra of alkenylsilanes

Conclusions The¹³C NMR spectra of 12 alkenylsilanes were measured and the values of the increments of the chemical shifts of the (CH₃)₃Si group were determined for some allylsilanes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 938–939, April, 1978.     

Cycloalumination of allylbenzenes with triethylaluminum in the presence of Cp<Subscript>2</Subscript>ZrCl<Subscript>2</Subscript>. One-pot synthesis of 2-benzylbutane-1,4-diols as precursors of dibenzylbutane lignans

One-pot synthesis of 2-[(hydroxy- and methoxyphenyl)methyl]butane-1,4-diols in an overall yield of 60–65% by cycloalumination of allylbenzenes (4-allyl-1-methoxybenzene, 4-allyl-1,2-dimethoxybenzene, 5-allyl-2-methoxyphenol, and 5-allyl-1,2,3-trimethoxybenzene) with triethylaluminum in the presence of Cp₂ZrCl₂ is reported for the first time. The developed procedure opens a new synthetic route to practically important β-substituted butane-1,4-diols that are precursors to dibenzylbutane lignans.     

Synthesis of bis-1,5,3-dithiazepanes on the basis of aromatic diamines

Russian Journal of Organic Chemistry - A procedure has been developed for the synthesis of N,N′-disubstituted bis-1,5,3-dithiazepanes by samarium-catalyzed recyclization of...     

Ozonides of perfluorooct-1-ene and perfluorooct-2-ene

Ozonides of higher perfluoroalkenes were prepared for the first time by ozonation of perfluorooct-1-and-2-enes in Freon-113. The structures of the resulting compounds were confirmed by¹³C NMR spectroscopy and GLC-mass spectrometry.     

A facile synthesis of spiro macrocarbocycles via the cycloalumination reaction of cyclic alkynes and alkadiynes

Zirconium-catalyzed cycloalumination of cycloalkadiynes assisted by Et₃Al, subsequent treatment of the in situ generated tricyclic dialuminum compounds with BrCH₂OMe and finally cyclopropanation of the obtained dispiro cyclopropyl dimethylene macrocarbocycles with Et₃Al-CH₂I₂ represents an efficient one-pot synthetic approach to prepare di- and tetraspiro cyclopropane-containing macrocarbocycles in very high yields.     

First examples of hydroxycyclopropanation in the series of lupane triterpenoids

Hydroxycyclopropanation at the ester group in the series of lupane triterpenoids was performed for the first time using 3,3-ethylenedioxybetulonic acid methyl ester and its 20,29-dihydro analog as substrates.