Methoxycarbonyl isocyanate

Reaction of 2-cyanomethylpyridine with iV-(l-aryl-l-chloro-2,2,2-trifluoroethyl)-iV -(4-methylphenyl)carbodiimides, and with (1,1,2,2,2-pentachloro- and l,l-dichloro-2,2,2-trifluoroethyl)isocyanates or A-methoxycarbonyl-l,2,2,2-tetrachloro-, — l-chloro-2,2-trifluoroacetaldehyde imines afforded 3-aryl-4-cyano-l-(4-methylphenyl)imino-3-trifluoromethyl-2,3-dihydro-17/-pyrido[l,2-f]pyrimidines and 4-cyano-3-trichloro-, 4-cyano-3-trifluoro-17/-pyrido[l,2-4pyrimidin-l-ones, respectively <2004CHE47>. Refluxing 2-cyanomethylpyridine and iV-(l-aryl-l-chloro-2,2,2-trifluoroethyl)isocyanates in benzene furnished l-aryl-4-cyano-l-trifluoromethyl-l,2-dihydro-3//-pyrido[l,2-4pyrimidin-3-ones. However, when the solution of the isocyanate was added dropwise to the solution of 2-cyanomethylpyridine, and the reaction mixture was then treated with NEt at room temperature, the isomeric 3-aryl-4-cyano-3-trifluoromethyl-2,3-dihydro-l//-pyr-ido[l,2-dpyrimidin-l-ones were obtained. Reaction of l-(acetyl- and benzoylmethylene)-6,7-dimethoxy-l,2,3,4-tetra-hydroisoquinolines with PhCONCS yielded 1-acetyl-, 1 -benzoyl-9,10-dime thoxy-3-pheny 1-6,7-dihydro-2//-pyrimido[6,l- ]isoquinoline-2-thiones <2003SL2369>. 

Pyridopyrimidine systems may also be accessed by in situ generation of pyridylisocyanates <2003TL2745>. Treatment of 2,3-pyridinccarboxylic anhydride with methanol leads to the formation of 2-(methoxycarbonyl)nicotinic acid that undergoes Curtius rearrangement on conversion to the 3-acyl azide with sodium azide and ethyl chloro-formate. Condensation of the resulting isocyanate with a series of amino acids leads to the synthesis of pyrido[3,2- T pyrimidines in good to excellent yield (Scheme 19). 

Dimethylcarbonate [DMC, (CH30)2C0] is a versatile chemical substance, which has been used mainly as a carbonylating, methylating, or methoxycarbonylating agent. It can be effectively used as an environmentally benign substitute for phosgene in polycarbonates and isocyanates synthesis, and for dimethyl sulfate in various methylation reactions. ... 

Reaction of 7V-ethoxycarbonyl-A( ,5-dimethylisothiourea with cyclohexyl isocyanate at room temperature gave the l,3,5-triazine-2,4(l//,3//)-dione (162) in 78% yield (Equation (28)) <85JAP60166672>. 7V-Methoxycarbonyl-0-methylisoureas (163) also react with isocyanates, and the intermediate (163) can be cyclized in methoxide/methanol at reflux temperature to the 1,3,5-triazine-... 

The developed solid-phase approach started with the preparation of immobilised ureas 114 obtained via acylation of amino acids linked to acid-labile Sasrin resin 104 with ortho-methoxycarbonyl aryl isocyanates or activated para-nitrophenyl carbamates 113. Alternatively, ureas of type 114 could also be generated by reaction of anthranilic esters 115 with immobilised amino acid-derived isocyanates (easily generated from tethered amino acids with triphosgene or phosgene in toluene in excess of a base such as 2,6-lutidine) or activated carbamates 116 (Scheme 4.1.23). 

Aromatic amines have been shown to be intermediates in the metal catalyzed carbonylation of nitroaromatics to aryl carbamates. Previous research established that the novel bis(methoxycarbonyl) complex, Ru(dppe)(C0)2[C(0)0Me]2, was the most abundant species present during catalysis. In this study, the complete kinetic analysis of the reaction of p-toluidine with Ru(dppe)(C0)2[C(0)0Me]2 established that the C-N bond formed by nucleophilic attack on a metal carbonyl, and that the organic product was removed from the metal by an intramolecular elimination of aryl isocyanate. 

Azides, Diazoalkanes, Diazirines, Azo-compounds, and Azines. Fluorinated alkanoyl azides have been dealt with already in other sections, mainly that concerned with isocyanates (see pp. 227,228, and 229). The azides CHFa Ns, (CFs)2C(N3) O SiMes, and (CF3)sC(Ns) O SOsO have been obtained from the reaction systems CHFsCl-NaNs-alkali-HsO-dioxan, (CF3)2CO-Me8Si N3,i and (CF3)2C(Ns) ONa-S2O5CIX (X = F or Cl), respectively. Eleven 2-azido-3,3>difluorocyclobutenes have been synthesized as indicated in Scheme 49 and converted thermally or photo-chemically into the corresponding 2,2-difluorocyclopropanes decomposition of the 1-cyano- and 1-methoxycarbonyl-cyclobutenes in the presence of electron ri( aromatics gave pyrrole derivatives. These results have been discussed in terms of the mechanistic pathways contained in Scheme SO Neber rearrangement with EtsN... 

Fowler, F. W. Cycloadditions of N-methoxycarbonyl-2,3-homopyrrole . Angew. Chem. 1971, 83, 148-149. Angew. Chem. Int. Ed. Engl. 1971,10, 135-136. Baldwin, J., Pinschmidt, R. K. jr. The Cycloaddition of Bicyclo2.1.0pent-2-ene with Tetracyanoethylene . Tetrahedron Lett. 1971, 935-938. Christl, M., Brunn und E., Lanzendoerfer, F. Reactions of Benzvalene with Tetracyanoethylene,2,3-Dichloro-5,6-dicyano-p-benzoquinone, Chlorosulphonyl Isocyanate, and Sulphur Dioxide. Evidence for Concerted 1,4-Cycloadditions to a Vinylcyclopropane System . J. Am. Chem. Soc. 1984,106, 373-382. 

Dimethoxy-4,4 -biphenylene diisocyanate 3,3 -Dimethoxy-4,4 -biphenylene isocyanic acid ester. See Dianisidine diisocyanate 3,3 -((3,3 -Dimethoxy-4,4 -biphenylylene) bis (azo)) bis (5-amino-4-hydroxy-2,7-naphthalenedisulfonic acid), tetrasodium salt. See Direct blue 15 3,3 -Dimethoxy-4,4 -biphenylylene diisocyanate. See Dianisidine diisocyanate 1,2-Di-(3-methoxycarbonyl-2-thioureido) benzene. See Thiophanate-methyl... 

This step is supposed to be favoured by the formation of an hydrogen bond between the amido hydrogen and the carbonyl oxygen of the methoxycarbonyl group. This interaction can be directly observed in the H NMR spectrum of (E) and is also analogous to the one found in the crystallographically characterised bis-carbamoyl complex Ru(DPPE)(C0)2(C(0)NH-/-Pr)2 previously discussed. As already mentioned, this complex eliminates isopropyl isocyanate and isopropylamine upon thermolysis. Alternative pathways for this elimination step can be disregarded on the basis of the kinetic data. However, this same data is not sufficient to indicate if either (E) or (F) or both are responsible for the... 

In the kinetic analysis this complex was considered as being in equilibrium with (F), but not as a possible intermediate in the production of isocyanate, due to the tram disposition of the carbamoyl and methoxycarbonyl groups, which does not allow an elimination reaction such as the one previously described. 

In reaction 27 (Ar = 3,4-diclorophenyl), no carbamate was formed at room temperature and pressure but, when the reaction was conducted by injecting complex (J) (Ar = Ph) into an autoclave containing a THF-MeOH solution preheated at 200 and under 60 atm CO, carbamate was formed along with aniline. This behaviour is consistent with the aforementioned competition between dehydrogenation of the coordinated methoxy group and CO insertion. In the first case, some aniline is formed which is not later carbonylated and so accumulates in solution. In the second, the aniline initially formed can further react with the methoxycarbonyl complex to afford carbamate (or isocyanate, if the mechanism proceeds analogously to the one found for Ru(CO)3(DPPE)). 

Chlorosulfonyl isocyanate added to a soln. of 17,18-bis(methoxycarbonyl)-6,14-ethenocodeine methyl ether in methylene chloride, refluxed 5 hrs., and the methanolic soln. of the crude product treated with excess diazomethane to methylate a small amount of demethylated material -> 1-chloro deriv. Y 81%. R. Giger, R. Rubinstein, and D. Ginsburg, Tetrahedron 29, 2393 (1973). 

Acylketenes, generated in the thermolysis of 4-oxo-l,3-dioxine derivatives, react with phenylcarbonyl-, methoxycarbonyl-, or phenoxycarbonyl isocyanates by a [4+2] cycloaddition reaction to give 2,4-dioxo-l,3- oxazines. ... 

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