The solution conformation of triarylmethyl radicals

Hyperfine coupling tensors to 1H, 2H, and natural abundance 13C were measured using X-band pulsed electron nuclear double resonance (ENDOR) spectroscopy for two triarylmethyl (trityl) radicals used in electron paramagnetic resonance imaging and oximetry: methyl tris(8-carboxy-2,2,6,6-tetramethyl-benzo[1,2d:4,5-d']bis(1,3)dithiol-4-yl) and methyl tris(8-carboxy-2,2,6,6-tetramethyl(-d3)-benzo[1,2d:4,5-d']bis(1,3)dithiol-4-yl). Quantum chemical calculations using density functional theory predict a structure that reproduces the experimentally determined hyperfine tensors. The radicals are propeller-shaped with the three aryl rings nearly mutually orthogonal. The central carbon atom carrying most of the unpaired electron spin density is surrounded by the sulfur atoms in the radical and is completely shielded from solvent. This structure explains features of the electron spin relaxation of these radicals and suggests ways in which the radicals can be chemically modified to improve their characteristics for imaging and oximetry.     

A catalytic method for chemoselective detritylation of 5′-tritylated nucleosides under mild and heterogeneous conditions using silica sulfuric acid as a recyclable catalyst

A rapid, mild and highly efficient procedure for the chemoselective deprotection of triphenylmethyl (trityl, Tr), p-anisyldiphenylmethyl (monomethoxytrityl, MMT) and di-(p-anisyl)phenylmethyl (dimethoxytrityl, DMT) groups from nucleoside trityl ethers has been established. The deprotection was achieved at room temperature, using a catalytic amount of silica sulfuric acid (SSA) in acetonitrile. The trityl nucleosides were deprotected in 2-17 min without any depurination. These conditions are compatible with other acid sensitive hydroxyl protecting groups such as p-methoxybenzyl (PMB), isopropylidene, cyclohexylidene, di-(p-anisyl)methylidene, triisopropylsilyl (TIPS) and t-butyldimethylsilyl (TBDMS).     

Chemoselective deprotection of trityl ethers using silica-supported sodium hydrogen sulfate

A highly selective method for the cleavage of trityl ethers over a wide range of functional groups has been developed using silica-supported sodium hydrogen sulfate (NaHSO₄-SiO₂) as a heterogeneous catalyst. The conversion occurred at room temperature and the yields of the alcohols were found to be excellent.     

Molecular and supramolecular helicity induction in trityl group-containing compounds: The case of chiral 3,3,3-triphenylpropionic acid derivatives

The process of dynamic chirality transmission from permanent chirality element to stereodynamic triphenylmethyl group placed in the distance of 4 bonds, has been studied for series of optically active 3,3,3-triphenylpropionic acid derivatives. Structural analysis, carried out with the use of complementary methods and supported by theoretical calculations, enabled us to determine the mechanism of chirality transmission. The observed chirality transfer phenomenon, demonstrated unequivocally as raising of non-zero Cotton effects in the region of UV absorption of trityl group, is a cascade process driven by weak intramolecular interactions. Despite the much larger inductor-effector distance, the sensitivity in chirogenesis is comparable to other stereodynamic probes reported so far. In the crystalline phase, the combination of trityl group with amino acid moiety results in the formation of helical superstructures, where individual molecules are held together by hydrogen bonding cascades. The proper combination of functionalities in the molecule skeleton allows, to some extent, the control over the association process and authorizes determination of the trityl group as the supramolecular synthon.     

原位生成的Ph3C+均相有机催化剂催化4,4’-芳亚甲基-二（3-甲基-1-苯基-1H-吡唑-5-醇）高效合成（英文）简

Trityl chloride (Ph₃CCl) efficiently catalyzes the condensation of 3-methyl-1-phenyl-1H-pyrazol- 5(4H)-one and aromatic aldehydes under mild and solvent-free conditions, affording 4,4''- (arylmethylene)-bis(3-methyl-1-phenyl-1H- pyrazol-5-ol)s in high to excellent yields and in short reaction time. The presence of the requisite organocatalytic trityl carbocation (Ph₃C⁺) species was confirmed by analysis of infrared, ¹H NMR, and ultra violet spectral data. A plausible mechanism was proposed for the reaction based on the observations and literature precedent.     

Trityl Chloride (TrCl): Efficient and Homogeneous Organocatalyst for the Solvent‐Free Synthesis of 14‐Aryl‐14H‐dibenzo[a,j]xanthenes by in situ Formation of Carbocationic System

Trityl chloride (triphenylmethyl chloride, TrCl, Ph₃CCl) is utilized as an efficient and homogeneous organocatalyst for the synthesis of 14‐aryl‐14H‐dibenzo[a,j]xanthenes from β‐naphthol and arylaldehydes under solvent‐free conditions. Moreover, a plausible mechanism is suggested based on the literature and on in situ formation of trityl carbocation with inherent instability during the reaction.     

A Facile,One‐Step Conversion of 6‐O‐Trityl and 6‐O‐TBDMS Monosaccharides into the Corresponding Formate Esters

A convenient method has been developed for a facile and high‐yield conversion of 6‐O‐tert‐butyldimethylsilyl and 6‐O‐trityl protected monosaccharides to their formate esters, which may serve as useful intermediates for the replacement of the primary hydroxyl group of sugars by other functional groups.