نتایج جستجو برای: diazomethane
تعداد نتایج: 337 فیلتر نتایج به سال:
The synthesis and enantiomeric features of 2-hydroxymethyl-tetrahydro-oxazolo[3,2-c]pyrimidine-5,7-(4H,6H)-diones (V) are. described. The diazomethane methylation of these bicyclic compounds afforded 2-hydroxymethyl-6-methyl-tetrahydro-oxazolo-[3,2-c]pyrimidine-5,7-(4H,6H)-diones (R)-(XXII) and (S)-(XXII), respectively. For the synthesis of (R)-V and (S)-V the respective 5-bromo-1-(2,3-dihydrox...
Temozolomide (TMZ) was FDA approved for treatment of glioblastoma (GBM) in 1995 and is a life-extending (and sometimes life-saving1) drug GBM other cancers.2 TMZ has been administered to thousands patients shipped around the world over three decades; typically ingest grams during standard regimen.3 We recently reported use as reagent synthesis methyl esters cyclopropanes with many benefits (inc...
The preparation of peptides terminating in -Arg-CHN2 has been attempted because of their potential value as proteinase inactivators. We have succeeded in one case, converting Cbz-Phe-ArgOH to the diazomethane without blocking the guanidino group. As expected from previous results with such reagents, the new derivative was extremely effective in inactivating a cysteine proteinase specific for cl...
Difluoromethyl-substituted cyclopropanes still remain one of the most challenging class of substrates. Despite significant progress in modern chemistry, an atom-economic and concise synthesis has not been described to date. Herein, we describe the first method for their catalytic, one-step synthesis using difluoromethyl diazomethane and a rhodium(ii) catalyst.
The electronic states of diazomethane in the region 3.00-8.00 eV have been characterized by ab initio calculations, and electronic transitions in the region 6.32-7.30 eV have been examined experimentally using a combination of 2 + 1 REMPI spectroscopy and photoelectron imaging in a molecular beam. In the examined region, three Rydberg states of 3p character contribute to the transitions, 2(1)A2...
The treatment of silk with an ethereal solution of diazometbane result ed in a rapid decrease in tyrosine content, with no appreciable d ecrease in tensile strength <o f the fibers . The results indicate that the hydroxyl groups of tyrosine in the 'Untreated fibers are free. The total methoxyl content after treatment of the fiber for 25 hours or longer was greater than could be accounted for by...
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