32894-08-9Relevant articles and documents
Compound embodiments that release H2S by reaction with a reactive compound and methods of making and using the same
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Page/Page column 39; 41-43, (2021/08/04)
Disclosed herein are embodiments of a donor compound that releases H2S by reacting with a reactive compound. The donor compound embodiments described herein can be used to deliver H2S to a subject or a sample and further can be used to administer therapeutic agents. The donor compound embodiments also can facilitate bioconjugation. Methods of making and using the donor compound embodiments also are disclosed.
Universal polymer analysis by 1H NMR using complementary trimethylsilyl end groups
Paech, Michael,Zehm, Daniel,Lange, Maik,Dambowsky, Ina,Weiss, Jan,Laschewsky, Andre
supporting information; experimental part, p. 8757 - 8765 (2010/08/13)
New degenerative chain transfer agents, namely 4-(trimethylsilyl)benzyl 4′-(trimethylsilyl)butane-dithioate, 4-(trimethylsilyl)benzyl 3′-(trimethylsilyl)propyl trithiocarbonate and their 3-(trimethylsilyl) benzyl isomers, that are two-fold labeled with complementary trimethylsilyl (TMS) markers, were designed and shown to be powerful tools for universal polymer analysis by conventional 1H NMR spectroscopy. Their use in controlled free radical polymerization, here the reversible addition- fragmentation chain transfer (RAFT) method, resulted in polymers with low polydispersities up to high molar masses, as well as with defined complementary TMS end groups. Thus, routine 1H NMR spectra allowed facile determination of the molar masses of polymers of various chemical structures up to at least 105 g/mol, and simultaneously provided crucial information about the content of end groups that is typically >95% when polymerizations are correctly performed. Polymerizations were carried out in various solvents for two standard monomers, namely n-butyl acrylate and styrene, as well as for two specialty monomers, so-called inimers, namely 2-(2-chloropropionyloxy)ethyl acrylate and 2-(2-chloropropionyloxy)ethyl acrylamide. The complementary end group markers revealed marked differences in the suitability of commonly used solvents for RAFT polymerization. The results demonstrate-beyond good polymerization control-that the new RAFT agents are universal, powerful tools for facile polymer analysis by routine 1H NMR spectroscopy, of their absolute molar masses as well as of the content of end groups. This is crucial information, e.g., for the synthesis of high-quality telechelics and, in particular, of block copolymers, which is difficult to obtain by other methods. Preliminary screening experiments indicate that similar uses can be envisaged for analogous ATRP systems.
Thiocarbonylthio compounds (S=C(Z)S-R) in free radical polymerization with reversible addition-fragmentation chain transfer (RAFT polymerization). Effect of the activating Group Z
Chiefari, John,Mayadunne, Roshan T.A.,Moad, Catherine L.,Moad, Graeme,Rizzardo, Ezio,Postma, Almar,Skidmore, Melissa A.,Thang, San H.
, p. 2273 - 2283 (2007/10/03)
Free-radical polymerization in the presence of suitable addition-fragmentation chain transfer agents [S=C(Z)S-R] (RAFT agents) possess the characteristics of a living polymerization (i.e., polymer products can be reactivated for chain extension and/or block synthesis, molecular weights are predetermined by RAFT agent concentration and conversion, narrow polydispersities are possible). Styrene polymerizations (110°C, thermal initiation) were performed for two series of RAFT agents [S=C(Z)S-CH2Ph and S=C(Z)S-C(Me)2CN]. The chain transfer coefficients decrease in the series where Z is Ph > SCH2Ph ～ SMe ～ Me ～ N-pyrrolo ? OC6F5 > N-lactam > OC6H5 > O(alkyl) ? N(alkyl)2 (only the first five in this series provide narrow polydispersity polystyrene ( trithiocarbonates ～ dithioalkanoates > dithiocarbonates (xanthates) > dithiocarbamates. However, electron-withdrawing substituents on Z can enhance the activity of RAFT agents to modify the above order. Thus, substituents that render the oxygen or nitrogen lone pair less available for delocalization with the C=S can substantially enhance the effectiveness of xanthates or dithiocarbamates, respectively. The trend in relative effectiveness of the RAFT agents is rationalized in terms of interaction of Z with the C=S double bond to activate or deactivate that group toward free radical addition. Molecular orbital calculations and the estimated LUMO energies of the RAFT agents can be used in a qualitative manner to predict the effect of the Z substituent on the activity of RAFT agents.
POLYMERIZATION WITH LIVING CHARACTERISTICS
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, (2008/06/13)
This invention concerns a free radical polymerization process, selected chain transfer agents employed in the process and polymers made thereby, in which the process comprises preparing polymer of general Formula (A) and Formula (B) comprising contacting: (i) a monomer selected from the group consisting of vinyl monomers (of structure CH2═CUV), maleic anhydride, N-alkylmaleimide, N-arylmaleimide, dialkyl fumarate and cyclopolymerizable monomers; (ii) a thiocarbonylthio compound selected from Formula (C) and Formula (D) having a chain transfer constant greater than about 0.1; and (iii) free radicals produced from a free radical source; the polymer of Formula (A) being made by contacting (i), (ii) C and (iii) and that of Formula (B) by contacting (i), (ii) D, and (iii); and (iv) controlling the polydispersity of the polymer being formed by varying the ratio of the number of molecules of (ii) to the number of molecules of (iii); wherein Q, R, U, V, Z, Z′, m, p and q are as defined in the text.
Synthesis of Dithioic Acid Esters by a Mitsunobu-Type Reaction of Alkanedithioic Acids and Alcohols
Kpegba, Kafui,Metzner, Patrick
, p. 137 - 139 (2007/10/02)
Alcohols react with dithioic acids in the presence of the complex of diisopropyl azodicarboxylate and triphenylphosphine to give various dithioic acid esters, via a Mitsunobu-type reaction.
A New Preparation of 5-(Alkylthio)-1,2-dithiole-3-thiones and a Highly Functionalized 1,3-Dithiole-2-thione
Lu, F. L.,Keshavarz-K., M.,Srdanov, G.,Jacobson, R. H.,Wudl, F.
, p. 2165 - 2169 (2007/10/02)
A "one-pot" preparation of the title 1,2-dithiole-3-thiones as well as the preparation and characterization of methyl 5-(methylthio)-2-thioxo-1,3-dithiole-4-dithiocarboxylate (3) are described.The X-ray structure determination of an iodine complex of the dithiolodithiole 5 is described in detail.The structure shows that this is a molecular solid with unusual three-dimensional intermolecular sulfur-sulfur "bonding".
STUDIES ON ORGANOPHOSPHORUS COMPOUNDS XLVIII Synthesis of Dithioesters from P,S-Containing Reagents and Carboxylic Acids and Their Derivatives
Yousif, N. M.,Pedersen, U.,Yde, B.,Lawesson, S.-O.
, p. 2663 - 2670 (2007/10/02)
2,4-Bismethylthio-1,3,2,4-dithiadiphosphetane 2,4-disulfide, IIa, is prepared from O,O-dimethyldithiophosphoric acid, Ia, and P4S10 at 160 deg C. 2,4-Bis(4-phenoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide, IIc, and 2,4-bis(4-phenyl-thiolphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide, IId, are prepared at 160 deg C from P4S10 and diphenylether and diphenylsulfides, respectively.Carboxylic acids RCOOH (R=CH3, C2H5, n-C3H7, n-C4H9, C6H5CH2, C6H5) react with compound Ia at 130 deg C to give the corresponding methyl dithioesters.Carboxylic acids RCOOH (R=C6H5-CH2, C6H5) react with compound Ib at 200 deg C for 15 min to give the corresponding ethyl dithioesters, while low boiling acids (R=CH3, C2H5, n-C3H7) yielded mixtures of the corresponding ethyl dithioester and ethyl carboxylate.Carboxylic acid chlorides RCOCl (R=ClCH2, C2H5, t-C4H9, C6H5CH2, C6H5, p-NO2C6H4) react with compound IIa at 80 deg C to give the corresponding methyl dithioesters in good yields.S-Substituted thioesters react with IIc at 85 deg C to give the corresponding dithioesters in good yields.Dihydro-2(3H)-furanone, VI, and 5-methyl-2(3H)-furanone, VII, react with IIa at 80 deg C to give dihydro-2(3H)-thiophenethione, VIII and 2,2'-dithiobis(5-methyl thiophene), IX, respectively.Also XI reacts with IIa, IIc, and IId to give VIII in nearly quantitative yields.
