A Mild and Simple Method for the Preparation of Isocyanates from Aliphatic Amines Using Trichloromethyl Chloroformate. Synthesis of an Isocyanate Containing an Activated Disulfide

Sigurdsson, Snorri Th.; Seeger, B.; Kutzke, Ursula; Eckstein, Fritz

doi:10.1021/jo9521920

Cited by 37 publications

(28 citation statements)

References 7 publications

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“…First, the requisite isocyanates were prepared by treating an appropriate amine with trichloromethyl chloroformate in CH 2 Cl 2 in the presence of non-nucleophilic amine base 1,8-bis(dimethylamino)naphthalene. 27 A pre- determined quantity of emetine dihydrochloride was then added to each isocyanate in CH 2 Cl 2 in the presence of 4-dimethylaminopyridine (DMAP) to produce compounds 7-9 in 74 to 85% yield. Unlike the thiourea synthesis, the urea analogs were isolated in a relatively high yield.…”

Section: Resultsmentioning

confidence: 99%

Design, Synthesis, and Evaluation of pH-Dependent Hydrolyzable Emetine Analogues as Treatment for Prostate Cancer

et al. 2012

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The N-2′ position of the natural product emetine has been derivatized to thiourea, urea, sulfonamide, dithiocarbamate, carbamate and pH responsive hydrolysable amide analogs. In-vitro studies of these analogs in PC3 and LNCaP prostate cancer cell lines showed that the analogs are generally less cytotoxic (average IC50 ranging from 0.079 μM to 10 μM) than emetine (IC50 ranging from 0.0237 to 0.0329 μM). The pH sensitive sodium dithiocarbamate salt 13 and the amide analogs 21, 22, 26 (obtained from maleic and citraconic anhydrides) showed the most promise as acid-activatable prodrugs under mildly acidic conditions found in the cancer micro-environment. These prodrugs released 12 – 83% of emetine at pH 6.5 and 41 – 95% emetine at pH 5.5. Compounds 13 and 26 were further shown to exhibit increased cytotoxicity in PC3 cell culture media that was already below pH 7.0 at the time of treatment.

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Section: Resultsmentioning

confidence: 99%

Design, Synthesis, and Evaluation of pH-Dependent Hydrolyzable Emetine Analogues as Treatment for Prostate Cancer

et al. 2012

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“…The catalyst is filtered off easily, and the inorganic reagent is washed In order to avoid the synthesis of the isocyanate using phosgene, three alternatives were tested. Diphosgene and triphosgene [16][17][18][19] are colourless solids and stable under ambient conditions. One molecule diphosgene releases two, triphosgene three equivalents of phosgene in situ.…”

Section: Resultsmentioning

confidence: 99%

4‐[¹⁸F]fluorophenyl ureas via carbamate‐4‐nitrophenyl esters and 4‐[¹⁸F]fluoroaniline

Olma¹,

Neumaier²,

Coenen³

2006

Labelled Comp Radiopharmac

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Four different no carrier added (n.c.a.) 4‐[18F]fluorophenylurea derivatives are synthesized as model compounds via two alternative routes. In both cases carbamate‐4‐nitrophenylesters are used as intermediates. Either n.c.a. 4‐[18F]fluoroaniline reacts with carbamates of several amines, or the carbamate of n.c.a. 4‐[18F]fluoroaniline is formed at first and an amine is added subsequently to yield the urea derivative. The choice of the appropriate way of reaction depends on the possibilities of precursor synthesis.The radiochemical yields reach up to 80% after 50 min of synthesis time while no radiochemical by‐products can be determined. These high yields were possible due to an optimized preparation of n.c.a. 4‐[18F]fluoroaniline with a radiochemical yield of up to 90%. From the various ways of its radiosynthesis, the substitution with n.c.a. [18F]fluoride on dinitrobenzene is chosen, using phosphorous acid and palladium black for reduction of the second nitro group. Copyright © 2006 John Wiley & Sons, Ltd.

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“…With the exception of 4 , which was purchased as an isothiocyanate, each photo-crosslinker was synthesized from its corresponding primary amine by treatment with diphosgene in the presence of N , N , N ′, N ′-tetramethyl-1,8-naphthalenediamine (Proton Sponge) (32). The compound 4-azidobenzoyl chloride ( 5 ) (21) was treated with 1,3-diaminopropane in a simple displacement reaction generating 6 in 12% yield.…”

Section: Resultsmentioning

confidence: 99%

Investigation of Mg2+- and temperature-dependent folding of the hairpin ribozyme by photo-crosslinking: effects of photo-crosslinker tether length and chemistry

Borda¹

2005

Nucleic Acids Research

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We have used photo-crosslinking to investigate the structure and dynamics of four-way junction hairpin ribozyme constructs. Four phenylazide photo-crosslinkers were coupled to 2′-NH2-modified U+2 in the substrate and irradiated at different Mg2+ concentrations and temperatures. Consistent with the role of divalent metal ions in hairpin ribozyme folding, we observed more interdomain crosslinks in the presence of Mg2+ than in its absence. In general, we observed intradomain crosslinks to nucleotides 2–11 and interdomain crosslinks to the U1A binding loop. Crosslinks to A26 and G36 in domain B were also observed when crosslinking was carried out at −78°C. In contrast to crosslinking results at higher temperatures (0, 25 and 37°C), similar crosslinks were obtained in the presence and absence of Mg2+ at −78°C, suggesting Mg2+ stabilizes a low-energy hairpin ribozyme conformation. We also evaluated the effects of photo-crosslinker structure and mechanism on crosslinks. First, most crosslinks were to unpaired nucleotides. Second, shorter and longer photo-crosslinkers formed crosslinks to intradomain locations nearer to and farther from photo-crosslinker modification, respectively. Finally, fluorine substitutions on the phenylazide ring did not change the locations of crosslinks, but rather decreased crosslinking efficiency. These findings have implications for the use of phenylazide photo-crosslinkers in structural studies of RNA.

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A Mild and Simple Method for the Preparation of Isocyanates from Aliphatic Amines Using Trichloromethyl Chloroformate. Synthesis of an Isocyanate Containing an Activated Disulfide

Cited by 37 publications

References 7 publications

Design, Synthesis, and Evaluation of pH-Dependent Hydrolyzable Emetine Analogues as Treatment for Prostate Cancer

Design, Synthesis, and Evaluation of pH-Dependent Hydrolyzable Emetine Analogues as Treatment for Prostate Cancer

4‐[¹⁸F]fluorophenyl ureas via carbamate‐4‐nitrophenyl esters and 4‐[¹⁸F]fluoroaniline

Investigation of Mg2+- and temperature-dependent folding of the hairpin ribozyme by photo-crosslinking: effects of photo-crosslinker tether length and chemistry

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A Mild and Simple Method for the Preparation of Isocyanates from Aliphatic Amines Using Trichloromethyl Chloroformate. Synthesis of an Isocyanate Containing an Activated Disulfide

Cited by 37 publications

References 7 publications

Design, Synthesis, and Evaluation of pH-Dependent Hydrolyzable Emetine Analogues as Treatment for Prostate Cancer

Design, Synthesis, and Evaluation of pH-Dependent Hydrolyzable Emetine Analogues as Treatment for Prostate Cancer

4‐[18F]fluorophenyl ureas via carbamate‐4‐nitrophenyl esters and 4‐[18F]fluoroaniline

Investigation of Mg2+- and temperature-dependent folding of the hairpin ribozyme by photo-crosslinking: effects of photo-crosslinker tether length and chemistry

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4‐[¹⁸F]fluorophenyl ureas via carbamate‐4‐nitrophenyl esters and 4‐[¹⁸F]fluoroaniline