Techniques of aligning carbon nanotubes

This paper reviews major techniques of aligning carbon nanotubes, either during the growth or by the post-growth processing. A number of post-processing alignment techniques are discussed, which employ mechanical stretching, fracture, compression, friction, filtration, fiber drawing, gas flow, liquid crystals, Langmuir-Blodgett technique, acoustic, magnetic and electric fields. The suitability of those techniques to industrial applications is analyzed.      

The Products of Suzuki Reaction of Ethyl 4-Chloro-5-Methylthieno[2,3-d]Pyrimidine-6-Carboxylate with Potassium Allyltrifluoroborate and Transformations Thereof

Chemistry of Heterocyclic Compounds - 5-Methylthieno[2,3-d]pyrimidine-6-carboxylates substituted with prop-1-en-1-yl and hexa-1,5-dien-3-yl fragments in the C-4 position of the heterocycle were...     

Cascade reaction of 2,3-naphthalenediol with benzene in the presence of aluminum halides

2,3-Naphthalenediol on superelectrophilic activation with aluminium halides smoothly reacts with benzene to give 4-((3-phenyl-1H-inden-1-yl)methyl)benzene-1,2-diol, which in turn undergoes intramolecular cyclization to form 5,10-methano-5-phenyldibenzo[a,d]cycloheptane-2,3-diol. The mechanistic aspects of these unusual transformations are discussed.     

Domino Michael/aza-Wittig reaction in the diastereoselective construction of spiro[azepane-4,3′-oxindoles]

A convenient synthetic strategy for the diastereoselective assembly of spiro[azepane-4,3′-oxindoles] was developed via a Staudinger/Michael/aza-Wittig/reduction/N-deprotection reaction sequence starting from PMB-protected oxindole-substituted ethylazides. The key step of the method is a domino self-catalytic Michael/aza-Wittig reaction wherein the phosphazene moiety acts first as the catalyst and then as the reactant, resulting in the formation of a seven-membered N-heterocycle.     

Diastereoselective synthesis of 3-tert-butyl-3,4-dihydropyrazolo[5,1-c][1,2,4]triazine-3,4-diyl dicarboxylates

The reactions of 3-tert-butyl-7-R¹-8-R²-pyrazolo[5,1-c][1,2,4]triazines (R¹ = H, Br; R² = Me, n-Bu) with N-bromosuccinimide in the presence of R³CO₂H (R³ = Me, t-Bu, Ph) afforded novel diastereomerically pure 3-tert-butyl-7-R¹-8-R²-3,4-dihydropyrazolo[5,1-c][1,2,4]triazine-3,4-diyl dicarboxylates. The structures of the isolated products were established on the basis of IR, ¹H, ¹³C, 2D NOESY NMR, high resolution mass spectrometry and X-ray single-crystal analysis. The steric and mechanistic origins of the observed regio- and stereoselectivity were also discussed.     

H2O‐Catalyzed Route to Early Lanthanide Tribromide THF and DME Solvates from Oxides

A convenient one‐pot synthetic protocol towards THF and DME solvates of lanthanum and other early lanthanide tribromides was developed using the water‐catalyzed reaction of lanthanide(III) oxides with highly reactive Me₃SiBr in situ formed from commercially available disilane Si₂Me₆ and Br₂. This practical route allows to obtain the target lanthanum tribromide solvates [LaBr₃(thf)₄] ( 1a ) and [LaBr₃(dme)₂]₂ ( 1b ) as well as analogous early lanthanide molecular tribromide solvates [NdBr₃(thf)₄] ( 2a ), [NdBr₃(dme)₂] ( 2b ), [SmBr₃(thf)₂] ( 3a ), and [SmBr₃(dme)₂] ( 3b ) difficult to prepare by other solution‐based procedures. The molecular structure of 1b· 2CH₂Cl₂ was determined by an XRD study.