Methyl dithiocarbonate carbonates

Finally, conjugated polymers may be prepared by ROMP of norbornene—bis(5-methyl dithiocarbonate) and bis (5-methyl carbonate) followed by thermal decomposition (Scheme 38) 51,352 g,g i y... 

Numerous research activities have focused on the improvement of the protective films and the suppression of solvent cointercalation. Beside ethylene carbonate, significant improvements have been achieved with other film-forming electrolyte components such as C02 [156, 169-177], N20 [170, 177], S02 [155, 169, 177-179], S/ [170, 177, 180, 181], ethyl propyl carbonate [182], ethyl methyl carbonate [183, 184], and other asymmetric alkyl methyl carbonates [185], vinylpropylene carbonate [186], ethylene sulfite [187], S,S-dialkyl dithiocarbonates [188], vinylene carbonate [189], and chloroethylene carbonate [190-194] (which evolves C02 during reduction [195]). In many cases the suppression of solvent co-intercalation is due to the fact that the electrolyte components form effective SEI films already at potential which are positive relative to the potentials of solvent co-intercalation. An excess of DMC or DEC in the electrolyte inhibits PC co-intercalation into graphite, too [183]. 

O-Allyl-5-alkyl dithiocarbonates react with Pd° catalysts to provide a ir-allyl complex with a thiocar-bonate serving as counterion. Under the reaction conditions the carbonate expels free methyl meicaptide, generating COS. Attack of the mercaptide was shown to occur exclusively via ligand addition (equation 195).221... 

Hu, Sun and Scott described recently an efficient synthesis of some taxadiene derivatives266. In their approach, alcohol (66) is treated with carbon disulphide followed by methyl iodide under standard conditions for the formation of xanthates, to afford the dithiocarbonate (67) in a process that presumably involved a Claisen rearrangement (Scheme 9). Interestingly, 67 undergoes smooth reaction with B SnH to provide the required products (68, 69)266. 

In Figure 4.14, we learned about the Chugaev elimination in connection with the synthesis of alkenes. The second (primary) product of this reaction is the dithiocarbonic acid 5-methyl ester (A). It equilibrates with the zwitterion B, which decomposes into carbon oxysulfide (a heterocumulene) and methanethiol (a heteroatom nucleophile). 

Carbon disulfide is the dithio derivative of C02. It is only a weak electrophile. Actually, it is so unreactive that in many reactions it can be used as a solvent. Consequently, only good nucleophiles can add to the C—S double bond of carbon disulfide. For example, alkali metal alkoxides add to carbon disulfide forming alkali metal xan-thates A (Figure 7.4). If one were to protonate this compound this would provide compound B, which is a derivative of free dithiocarbonic acid. It is unstable in the condensed phase in pure form, just as free carbonic acid and the unsubstituted carbamic acid (Formula B in Figure 7.3) are unstable. Compound B would therefore decompose spontaneously into ROH and CS2. Stable derivatives of alkali metal xanthates A are their esters C. They are referred to as xanthic add esters or xanthates. They are obtained by an alkylation (almost always by a methylation) of the alkali metal xanthates A. You have already learned about synthesis applications of xanthic acid esters in Figures 1.32, 4.13, and 4.14. 

Oxygen-sulfur heteroatom exchange has been achieved with 3-methyl-benzene thiazole-2-thione in the presence of trifluoroacetic acid and with l-phenyl-5-mercaptotetrazole. Thiirane can be prepared from oxirane on a support impregnated with alkali metal salts, by decomposition of the dithiocarbon-ate formed with carbon disulfide. A macrocyclic ether, perhydrobenzo-18-crown-6, plays a role in the nucleophilic reaction of oxirane with KCNS, which leads to thiirane in good yield. ... 

An ingenious solution to the problem of slowly reacting (weakly basic) o-aminonitriles was to replace the carbon disulfide by potassium O-ethyl dithiocarbonate ( xanthogenate ) (EtO—CS2K),188 which slowly liberates carbon disulfide above 110°C. Thus, 2-amino-5-nitrobenzonitrile gave an excellent yield of 6-nitroquinazoline-2,4-dithione when boiled with this salt in butanol for 4 hr.189 Excellent yields of 8-azapurine-2,6-dithione and its 9-methyl and 9-benzyl derivatives were similarly obtained.179 For more reluctant reactions, boiling dimethylformamide proved to be a useful solvent.189... 

Cyclic methylethylene carbonate. See Propylene carbonate Cyclic-S,S-(6-methyl-2,3-quinoxalinediyl) dithiocarbonate. See Chinomethionat Cyclic neopentanetetrayl bis (2,4-di-t-butylphenyl) ester phosphorous acid. See Bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite... 

Methyl-2,3-quinoxaline dithiocarbonate 6-Methyl-2,3-quinoxalinedithiol cyclic carbonate 6-Methyl-2,3-quinoxalinedithiol cyclic dithiocarbonate. See Chinomethionat Methyl rapeseedate CAS 73891-99-3... 

Synonyms Bay 36205 Bayer 4964 Bayer 36205 Chinomethionat Chinomethionate Cyclic 5, 5 -(6-methyl-2,3-quinoxalinediyl) dithiocarbonate ENT 25606 Erade Erazidon Forstan 6-Methyl-l,3-dithioIo[4,5- ]quinoxalin-2-one 6-Methyl-2-oxo-l,3-dithi-olo[4,5-Z ]quinoxaline 6-Methyl-2,3-quinoxaline dithiocarbonate 6-Methyl-2,3-quinoxa-linedithiol cyclic carbonate 6-Methyl-2,3-quinoxalinedithiol cyclic dithiocarbonate 6-Methyl-2,3-quinoxalinedithiol cyclic 5, 5 -dithiocarbonate 6-Methylquinoxaline-2,3-dithi-olcyclocarbonate S, S -(6-Methylquinoxaline-2,3-diyl) dithiocarbonate Morestan Mores-tane Oxythioquinox Quinomethoate SS 2074. 

Scheme 8.69. The Chugaev reaction. The salt of an alcohol is allowed to react with carbon disulfide, producing the sodium salt of a dithiocarbonate derivative, which, on Sn2 reaction with methyl iodide (CH3I), produces the corresponding xanthate ester. Heating the xanthate (pyrolysis) results in loss of carbon oxysulfide (COS), methane thiol (thiomethane), and the corresponding alkene.

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