Synthesis of benzocycloheptene derivatives as CCR5 antagonists with potent anti-HIV activity

A series of novel benzocycloheptene derivatives have been synthesized.Their structures were confirmed by MS and ^1H-NMR. These compounds exhibited potent anti-HIV-1 activities.     

Preparation of 2-phospholene derivatives from zirconacyclopentenes

Zirconacyclopentenes, which are easily prepared from alkynes, alkenes, and zirconocene compounds, reacted with dichlorophenylphosphine to give 2-phospholene in high yields. The reaction was performed conveniently in one-pot from an alkyne, alkene, dichlorophosphine, and zirconocene compounds.     

Lewis Acid mediated reactions of zirconacyclopentadienes with aldehydes: one-pot synthetic route to indene and cyclopentadiene derivatives from aldehydes and benzyne or alkynes

One-pot procedures for the preparation of highly substituted indenes, tetrahydroindenes, and cyclopentadienes have been developed by using a combination of zirconocene-mediated Cbond;C-bond-forming reactions with Lewis acid mediated activation of carbonyl groups. The carbonyl groups of aldehydes were deoxygenated in the reaction and behaved formally as a one-carbon unit. A variety of Lewis acids were checked and showed different reactivities in this reaction.     

Preparation and characterization of silica-pillared derivatives from kanemite

The silica-pillared derivatives from kanemite (NaHSi(2)O(5).3H(2)O) were prepared by intercalation of dialkyldimethylammonium (DADMA) ion and pillaring with tetraethylorthosilicate. The formation of silica pillars between the silicate sheets was demonstrated by X-ray diffraction, (29)Si CP/MAS NMR, and TEM observation. The basal spacing depended on the chain length of DADMA. Nitrogen adsorption study showed that the specific surface area was enlarged over 1000 m(2) g(-1) by the pillaring and that the pore size was in the micropore region. Water and benzene adsorption isotherms revealed that the surface properties of the pillared derivatives show hydrophobic character.     

Remarkable effect of copper chloride on diiodination of zirconacyclopentadienes

Treatment of zirconacyclopentadienes with two equiv of iodine in THF in the presence of 1.0 equiv of CuCl gave diiododienes in good to high yields without formation of monoiododienes. This is in sharp contrast to the case without CuCl which afforded monoiododienes as major products. For zirconacyclopentenes, CuCl was also effective but the use of ICI was more practical. When zirconacyclopentenes were treated with 2 equiv of ICI, only diiodination products were formed. Preparation of silacyclopentadienes or spiro compounds using the diidodienes was demonstrated.     

Effect of lithium chloride on allylation of zirconacyclopentadienes

The effects of lithium chloride on the allylation of zirconacyclopentadienes with allylic halides in the presence of CuCl have been studied. It is found that mono-allylation products are formed predominantly in the absence of lithium chloride, while the presence of lithium chloride leads to the formation of di-allylation products.     

Preparation of undecacarbonyltriosmium derivatives

Undecacarbonyltriosmium derivatives have been prepared by treatment of dodecacarbonyltriosmium with amine oxide in low ratio $\text{(1}\text{1)}$. Substitution reactions with halogen acids lead to HOs(CO)₁₁X derivatives which readily lose carbon monoxide to yield HOs₃(CO)₁₀X compounds.     

Synthesis of vitamin B6 derivatives I. Preparation of some isopyridoxamine derivatives from isopyridoxal

Improved syntheses of isopyridoxal and isopyridoxamine are described. New 5-N-substituted isopyridoxamine derivatives resulting from condensation followed by reduction of the carbonyl group of isopropylideneisopyridoxal with aniline, 2-aminothiazole and benzylamine are also reported.     

Preparation of primary aliphatic and alicyclic amines from thiophene derivatives

Summary A new method was developed for the preparation of primary aliphatic and alicyclic amines by the reductive desulfurization of oximes and amines containing a thiophene nucleus with the aid of Raney nickel.     

Cycloaddition reaction of zirconacyclopentadienes to quinones: synthesis of higher para-quinones

Efficient synthetic approaches to higher para-dihydroquinones and -quinones have been developed through zirconium/CuCl-mediated cycloaddition reactions of two alkynes and quinone in a one-pot procedure.     

Preparation of silyl enol ethers from acyloin derivatives using silyllithium reagents

A new method for the regioselective preparation of silyl enol ethers from acyloin derivatives using silyllithium reagents has been developed. Both dimethylphenyl- and methyldiphenylsilyllithium were found to be effective, the latter providing greater stereocontrol. The reaction is believed to proceed via Brook rearrangement assisted by expulsion of the adjacent leaving group. A number of acyclic acyloin derivatives were reacted to form the corresponding silyl enol ethers in good to excellent yield.     

Preparation of 1,3-disubstituted isoquinoline derivatives from N-boc-3-substituted-1,2-dihydroisoquinolines

3-Substituted N-Boc-1,2-dihydroisoquinolines 2 can be functionalized at the 1-position via lithiation and subsequent electrophilic trapping. The resulting products 3 can be deprotected and oxidized to afford the corresponding 1,3-disubstituted isoquinolines 5 . Deprotection of dihydroisoquinoline 3k followed by sodium borohydride reduction affords the cis-1,3-disubstituted tetrahydroisoquinoline 11 . The 1,3-disubstituted N-Boc-1,2-dihydroisoquinoline 3g is efficiently alkylated at the 1-position to give 1,1,3-trisubstituted analogs 12 .     

Preparation of substituted enol derivatives from terminal alkynes and their synthetic utility

Stereodefined enol derivatives of aldehydes are prepared from terminal alkynes. Specifically, terminal alkynes are known to undergo Cp2ZrCl2-catalyzed methylalumination. Here, we show that the resultant vinylalanes can be oxygenated with peroxyzinc species to generate trisubstituted enolates. Electrophilic trapping with carboxylic anydrides or silyl triflates yields trisubstituted enol esters or silanes, respectively. The tandem carbometalation/oxygenation tolerates free and protected alcohols, heterocycles, olefins, and nitriles. Stereodefined enol esters can undergo asymmetric dihydroxylation to yield optically active alpha-hydroxy aldehydes. Reduction with NaBH4 provides the diols of 1,1-disubstituted olefins in excellent ee. An application of this methodology to the enantioselective synthesis of the insect pheromone frontalin is presented. Finally, alpha-hydroxy aldehydes are shown to undergo homologation to a terminal alkyne, reductive amination, oxidation and olefination. Preliminary results indicate that tandem carbometalation/amination can be accomplished with azodicarboxylates. In this way, ene-hydrazines are formed in excellent yield.     

Acetylene derivatives Communication 191. Preparation of acids from tertiary acetylenic alcohols

Summary A method was developed for the conversion of tertiary acetylenic alcohols to unsaturated acids.