Search results for "Tert butyl"

Bis(tert-butylammonium) oxalate

2006

The component species in the title compound, 2C4H12N2+·C2O42−, inter­act by way of N—H⋯O hydrogen bonds, resulting in a layered network. N and two C atoms of the cation possess site symmetry m and the C atom of the anion has site symmetry 2.

2,7-Di-tert-butyl-9,9-dimethyl-4,5-bis(4-tritylanilinocarbonyl)-9H-xanthene methanol trisolvate monohydrate

2006

The title compound, C75H68N2O3·3CH3OH·H2O, was synthesized starting from the corresponding acid and p-tritylaniline. Single crystals were obtained from a methanol solution as a solvate, with three methanol mol­ecules and one water mol­ecule. The solid-state structure proves the existence of an intra­molecular bifurcated hydrogen bond between one amide H atom and the carbonyl and xanthene O atoms. The packing is stabilized by inter­molecular hydrogen bonds.

Di-tert-butyl Phosphonate Route to the Antiviral Drug Tenofovir

2021

Di-tert-butyl oxymethyl phosphonates were investigated regarding their suitability for preparing the active pharmaceutical ingredient tenofovir (PMPA). First, an efficient and simple access to the crystalline di-tert-butyl(hydroxymethyl)phosphonate was developed. O-Mesylation gave high yields of the active phosphonomethylation reagent. For the synthesis of tenofovir, a two-step sequence was developed using Mg(OtBu)2 as the base for the alkylation of (R)-9-(2-hydroxypropyl)adenine. Subsequent deprotection could be achieved with aqueous acids. (Di-tert-butoxyphosphoryl)methyl methanesulfonate showed to be the most efficient electrophile tested, affording PMPA in 72% yield on a 5 g scale. The …

6,6′-[(3,3′-Di-tert-butyl-5,5′-dimethoxy-1,1′-biphenyl-2,2′-diyl)bis(oxy)]bis(dibenzo[d,f][1,3,2]dioxaphosphepine) benzene monosolvate

2019

The crystal structure of the benzene monosolvate of the well known organic diphosphite ligand BIPHEPHOS, C46H44O8P2·C6H6, is reported for the first time. Single crystals of BIPHEPHOS were obtained from a benzene solution after layering with n-heptane at room temperature. One specific property of this type of diphosphite structure is the twisting of the biphenyl units. In the crystal, C—H...π contacts and π–π stacking interactions [centroid-to-centroid distance = 3.8941 (15) Å] are observed.

Synthesis of fluorinated Thomsen-Friedenreich antigens: direct deoxyfluorination of αGalNAc-threonine tert-butyl esters.

2011

Selectively 6-fluorinated analogs of the tumor-associated T(N) antigen Fmoc-Thr(α-O-GalNAc)-OtBu can be efficiently prepared using DAST-mediated de(hydr)oxyfluorination reactions of preformed and orthogonally protected glycosyl amino esters without affecting the labile protecting groups and O-glycosidic linkages. The resulting mono- and difluorinated T(N) analogs are interesting building blocks for non-hydrolyzable mucin-type antigen mimetics, as illustrated by the unprecedented synthesis of two different multiply fluorinated Thomsen-Friedenreich derivatives. The reported deoxyfluoro antigen analogs represent important functional probes for carbohydrate-binding proteins and glycosyl-process…

1975

The formation and the behaviour of radiation induced free radicals in poly[1-(tert-butoxy carbonylthio)ethylene] (2) and in a statistical copolymer 4 from O-tert-butyl S-vinyl thiocarbonate (1) with N-vinylpyrrolidone (1:1) was studied, using ESR spectroscopy. After γ-irradiation at 77 K, tert-butyl radicals and other species were detected in the polymers. The yield for the homopolymer was evaluated to be Gtert-butyl = 0.18. Investigations on the behaviour of radicals with an annealing procedure revealed, that at first the tert-butyl radicals disappear with increasing temperature and that a further warming up leads to a concentration rise of this radical species. A radical cation localized …