A mild deprotection strategy for allyl-protecting groups and its implications in sequence specific dendrimer synthesis

A mild deprotection strategy for allyl ethers under basic conditions in the presence of a palladium catalyst is described. Under these conditions, aryl allyl ethers can be cleaved selectively in the presence of alkyl allyl ethers. These conditions are also effective in the deprotection of allyloxycarbonyl groups. The utility of the current methodology in sequence specific dendrimer synthesis is demonstrated.     

Three tetrahydroisoquinolinedione derivatives

N‐(2‐Chloro­benzyl)‐1,2,3,4‐tetra­hydro­iso­quinoline‐1,3‐dione, C₁₆H₁₂ClNO₂, crystallizes in P2₁/n with three crystallographically independent mol­ecules in the asymmetric unit, which differ slightly in conformation, N‐(2‐bromo‐4‐methyl­phenyl)‐1,2,3,4‐tetra­hydro­iso­quinoline‐1,3‐dione, C₁₆H₁₂BrNO₂, crystallizes in P2₁/n with one mol­ecule in the asymmetric unit andN‐(2,3‐di­chloro­phenyl)‐1,2,3,4‐tetra­hydro­iso­quinoline‐1,3‐dione, C₁₅H₉Cl₂NO₂, crystallizes in P2₁/c with one mol­ecule in the asymmetric unit. In all three structures, the heterocyclic rings adopt approximately planar conformations. The pyridine rings are orthogonal to the substituted phenyl rings. In all three structures, the crystal packing is stabilized by intermolecular C—H?O hydrogen bonds.     

Transfer measurements for the Ti+Ni systems at near barrier energies

Large enhancements have been observed in the sub-barrier fusion cross sections for Ti+Ni systems in our previous studies. Coupled channel calculations incorporating couplings to 2⁺ and 3⁻ states failed to explain these enhancements completely. A possibilty of transfer channels contributing to the residual enhancements had been suggested. In order to investigate the role of relevant transfer channels, measurements of one- and two-nucleon transfer were carried out for ^46,48Ti+⁶¹Ni systems. The present paper gives the results of these studies.     

1‐(2‐Hydro­xy‐4‐methoxy­phenyl)‐3‐(2,3,4‐tri­methoxy­phenyl)­prop‐2‐en‐1‐one

The title compound, C₁₉H₂₀O₆, crystallizes in the centrosymmetric space group P2₁/c with one mol­ecule in the asymmetric unit. The mol­ecule is approximately planar and the dihedral angle between the phenyl rings is 11.0 (1)°. The H atoms of the central propenone group are trans. There is an intramolecular O—H⃛O hydrogen bond and the mol­ecules are crosslinked by four intermolecular C—H⃛O hydrogen bonds, producing a three‐dimensional network.     

Growth,spectral, and thermal characterization of the NLO crystal: semicarbazone of <Emphasis Type="SmallCaps">dl</Emphasis>-camphor (SDLC)

Semicarbazone of dl-camphor (SdlC) crystals were grown using methanol as a solvent by slow evaporation solution growth technique at room temperature. Formation of the product and the presence of various functional groups present in the grown crystal have been identified using FTIR spectra. Single crystal XRD study was conducted to obtain the crystal structure and lattice parameters. The grown crystal was subjected to ¹HNMR and ¹³CNMR spectral studies and TG-DTA in order to confirm its structure, purity, and stability, respectively. The optical transparency of the crystal was tested using UV–Vis–NIR spectroscopy. The nonlinear optical (NLO) property of the grown crystal was confirmed from the second harmonic generation (SHG) by Kurtz–Perry powder test.     

3‐Amino‐4′‐methyl­‐5‐ethylbi­phenyl‐2,4‐dicarbo­nitrile and 3‐amino‐4′‐(N,N‐diethyl­amino)‐5‐ethyl­bi­phenyl‐2,4‐dicarbo­nitrile

In the title compounds, C₁₇H₁₅N₃ and C₂₀H₂₂N₄, the methyl derivative crystallizes with two mol­ecules in the asymmetric unit, while the N,N‐diethyl­amino derivative crystallizes with one mol­ecule per asymmetric unit. The bi­phenyl twist angle for both mol­ecular structures is approximately 45°. The molecular packing is stabilized by N—H?N hydrogen bonds.     

10‐(4‐Fluorophenyl)‐3,3,6,6,9‐pentamethyl‐3,4,6,7,9,10‐hexahydroacridine‐1,8(2H,5H)‐dione and 10‐(4‐fluorophenyl)‐3,3,6,6‐tetramethyl‐9‐­propyl‐3,4,6,7,9,10‐hexahydroacridine‐1,8(2H,5H)‐dione

10‐(4‐Fluoro­phenyl)‐3,3,6,6,9‐penta­methyl‐3,4,6,7,9,10‐hexa­hydro­acridine‐1,8(2H,5H)‐dione, C₂₄H₂₈FNO₂, (I), crystallizes with two crystallographically independent mol­ecules (which differ slightly in conformation), while 10‐(4‐fluoro­phenyl)‐9‐propyl‐3,3,6,6‐tetra­methyl‐3,4,6,7,9,10‐hexa­hydro­acridine‐1,8(2H,5H)‐dione, C₂₆H₃₂FNO₂, (II), crystallizes with one mol­ecule per asymmetric unit. In both structures, the central ring in the acridine moiety is in a sofa conformation, while the outer rings adopt intermediate half‐chair/sofa conformations. The central pyridine ring is orthogonal to the substituted phenyl ring. In both structures, the packing of the crystal is stabilized by C—H?O intermolecular hydrogen bonds.     

Simple and efficient methods of synthesis of 3,3-diarylcyclobutanone and 3,3-diarylcyclobutylamine derivatives using the TiCl4/R3N reagent system

[reaction: see text] The iminium ions generated in situ by the oxidation of N,N-diisopropyl-N-benzylamine using iodine react with diaryl ketones in the presence of TiCl4/R3N to give the corresponding 3,3-diarylcyclobutanones in moderate to good yields (49-86%). The 3,3-diarylcyclobutanone iminium ions formed in this transformation was reduced in situ with B2H6 to produce the corresponding 3,3-diarylcyclobutylamines (52-79% yields), a class of compounds with potential antidepressant activity. In addition, a series of N,N-dimethyl-3,3-diarylcyclobutylamines were synthesized by the reductive amination of the corresponding 3,3-diarylcyclobutanone derivatives.