- A Mild Heteroatom (O -, N -, and S -) Methylation Protocol Using Trimethyl Phosphate (TMP)-Ca(OH) 2Combination
-
A mild heteroatom methylation protocol using trimethyl phosphate (TMP)-Ca(OH)2combination has been developed, which proceeds in DMF, or water, or under neat conditions, at 80 °C or at room temperature. A series of O-, N-, and S-nucleophiles, including phenols, sulfonamides, N-heterocycles, such as 9H-carbazole, indole derivatives, and 1,8-naphthalimide, and aryl/alkyl thiols, are suitable substrates for this protocol. The high efficiency, operational simplicity, scalability, cost-efficiency, and environmentally friendly nature of this protocol make it an attractive alternative to the conventional base-promoted heteroatom methylation procedures.
- Tang, Yu,Yu, Biao
-
-
- The energy-transfer-enabled biocompatible disulfide–ene reaction
-
Sulfur-containing molecules participate in many essential biological processes. Of utmost importance is the methylthioether moiety, present in the proteinogenic amino acid methionine and installed in tRNA by radical-S-adenosylmethionine methylthiotransferases. Although the thiol–ene reaction for carbon–sulfur bond formation has found widespread applications in materials or medicinal science, a biocompatible chemo- and regioselective hydrothiolation of unactivated alkenes and alkynes remains elusive. Here, we describe the design of a general chemoselective anti-Markovnikov hydroalkyl/aryl thiolation of alkenes and alkynes—also allowing the biologically important hydromethylthiolation—by triplet–triplet energy transfer activation of disulfides. This fast disulfide–ene reaction shows extraordinary functional group tolerance and biocompatibility. Transient absorption spectroscopy was used to study the sensitization process in detail. The hereby gained mechanistic insights were successfully employed for optimization of the catalytic system. This photosensitized transformation should stimulate bioimaging applications and carbon–sulfur bond-forming late-stage functionalization chemistry, especially in the context of metabolic labelling.
- Teders, Michael,Henkel, Christian,Anh?user, Lea,Strieth-Kalthoff, Felix,Gómez-Suárez, Adrián,Kleinmans, Roman,Kahnt, Axel,Rentmeister, Andrea,Guldi, Dirk,Glorius, Frank
-
p. 981 - 988
(2018/08/31)
-
- Efficient Swern oxidation and Corey-Kim oxidation with ion-supported methyl sulfoxides and methyl sulfides
-
The Swern oxidation of various benzylic and allylic alcohols, primary alcohols, and secondary alcohols with two ion-supported methyl sulfoxides A-1 (C6) and B-1 (C10), and oxalyl chloride in the presence of triethylamine in dichloromethane, followed by simple diethyl ether extraction of the reaction mixture, gave the corresponding aldehydes and ketones, respectively, in good yields with high purity. Similarly, the Corey-Kim oxidation of various benzylic and allylic alcohols, primary alcohols, and secondary alcohols with two ion-supported methyl sulfides A-2 (C6) and B-2 (C10), and N-chlorosuccinimide in the presence of triethylamine in dichloromethane, followed by simple diethyl ether extraction of the reaction mixture, furnished the corresponding aldehydes and ketones, respectively, in good yields with high purity. Both reactions did not produce any unpleasant odor at all. In the Swern oxidation, ion-supported methyl sulfides were recovered in high yields and could be re-oxidized to produce ion-supported methyl sulfoxides A-1 (C6) and B-1 (C10), for reuse in the same oxidation. In the Corey-Kim oxidation, ion-supported methyl sulfides A-2 (C6) and B-2 (C10) were recovered in high yields and could be also reused for the same oxidation.
- Tsuchiya, Daisuke,Tabata, Masayuki,Moriyama, Katsuhiko,Togo, Hideo
-
experimental part
p. 6849 - 6855
(2012/08/28)
-
- Swern oxidation of alcohols with ion-supported methyl sulfoxide and oxalyl chloride
-
The oxidation of primary and secondary alcohols with ion-supported methyl sulfoxide and oxalyl chloride in the presence of triethylamine in dichloromethane efficiently proceeded to give the corresponding aldehydes and ketones, respectively, in good yields with high purity. Isolation of the product was achieved very easily by simple diethyl ether extraction of the reaction mixture and subsequent removal of solvent from the extract. The reaction did not produce any unpleasant odor. Furthermore, ion-supported methyl sulfide was recovered in good yield and could be re-oxidized to ion-supported methyl sulfoxide for reuse in the same oxidation. Georg Thieme Verlag Stuttgart · New York.
- Tsuchiya, Daisuke,Moriyama, Katsuhiko,Togo, Hideo
-
experimental part
p. 2701 - 2704
(2012/01/03)
-
- Assessment of heat-sensitive thiophosphate protecting groups in the development of thermolytic DNA oligonucleotide prodrugs
-
Heat-sensitive thiophosphate protecting groups derived from the alcohol 4 or 10 have provided insights in the design of DNA oligonucleotide prodrugs. Indeed, functional groups stemming from the alcohol 9, 15, 16 or 22 may be applicable to thiophosphate protection of immunostimulatory CpG DNA motifs, whereas those originating from the alcohol 3, 5, 12, 13, 18, 20 or 22 offer adequate protection of terminal phosphodiester functions against ubiquitous exonucleases that may be found in biological environments. Functional groups derived from the alcohol 9, 15, 16, 19 or 23 are suitable for the protection of phosphodiester functions flanking the CpG motifs of immunomodulatory DNA sequences.
- Ausín, Cristina,Kauffman, Jon S.,Duff, Robert J.,Shivaprasad, Shankaramma,Beaucage, Serge L.
-
experimental part
p. 68 - 79
(2010/03/04)
-
- TOTAL SYNTHESIS OF THE RACEMIC ALKALOID DIPTOCARPAMINE
-
A route for the synthesis of racemic diptocarpamine from hex-5-enoic acid has been developed.
- Tolstikova, O. V.,Tolstikov, A. G.,Shmakov, V. S.,Galkin, E. G.,Vyrypaev, E. M.,et al.
-
p. 199 - 202
(2007/10/02)
-