- Latent Nucleophilic Carbenes
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Using DFT and ab initio calculations, we demonstrate that noncyclic formamidines can undergo thermal rearrangement into their isomeric aminocarbenes under rather mild conditions. We synthesized the silylformamidine, for which the lowest activation energy in this process was predicted. Experimental studies proved it to serve as a very reactive nucleophilic carbene. The reactions with acetylenes, benzenes, and trifluoromethane proceeded via insertion into sp, sp2, and spCH bonds. The carbene also reacted with the functional groups, such as CHO, COR, and CN at double or triple bonds, displaying high mobility of the trimethylsilyl group. The obtained silylformamidine can be considered as a latent nucleophilic carbene. It can be prepared in bulk quantities, stored, and used when the need arises. Calculation results predict similar behavior for some other silylated formamidines and related compounds.
- Marchenko, Anatoliy,Koidan, Georgyi,Hurieva, Anastasiya,Shvydenko, Kostiantyn,Rozhenko, Alexander B.,Rusanov, Eduard B.,Kyrylchuk, Andrii A.,Kostyuk, Aleksandr
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p. 373 - 385
(2021/12/27)
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- Short synthesis of methylenecyclopentenones by intermolecular Pauson-Khand reaction of allyl thiourea
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N,N,N′-Trimethylallylthiourea promotes the intermolecular Pauson-Khand reaction with alkynes in the presence of Co2(CO)8 and moderate pressure of CO followed by thiourea elimination allowing the formation of methylenecyclopentenone d
- Petrovski, ?eljko,Martins, Bruno M.R.,Afonso, Carlos A.M.
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supporting information; experimental part
p. 3356 - 3359
(2010/08/19)
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- Quantitative solid-state reactions of amines with carbonyl compounds and isothiocyanates
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A series of solid-state reactions is reported of gaseous or solid amines with aldehydes to give imines, with solid anhydrides to give diamides (therefrom imides) or amidic carboxylic salts or imides, with solid imides to give diamides, with solid lactones or carbonates to give functionalized carbamic esters, with polycarbonates to give degradative aminolysis, and with solid isothiocyanates to give thioureas. Diamides give imides by solid-state thermolysis or acid catalysis. Various double, two-step, 3-cascade, and sequential reactions are reported in the solid state without melting. The yields are quantitative in 53 reported reaction examples and no workup (except for washings in four cases) is required in the 100% yield reactions. Three initially solid-state reactions but with liquid product were not quantitative. An upscaling to the kg scale shows promise of the technique for large scale applications. Supermicroscopic analyses with AFM elucidate the solid-state mechanism by virtue of far-reaching anisotropic molecular movements in three-step processes. Gas-solid aminolyses of polycarbonates are also studied with AFM. The implications to sustainable chemistry are discussed. (C) 2000 Elsevier Science Ltd.
- Kaupp, Gerd,Schmeyers, Jens,Boy, Juergen
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p. 6899 - 6911
(2007/10/03)
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- A high-yielding and facile preparation of N-substituted thioureas by substitution of nitrosothioureas with alkylamines
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High yields of N-mono- or di- alkyl substituted thioureas are readily achieved by the reaction of nitrosothioureas with alkylamines in acetonitrile at room temperature.
- Xian,Zhu,Li,Cheng
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p. 1957 - 1960
(2007/10/03)
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- Pesticidal compositions containing phosphoric esters and divalent sulphur compounds
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Pesticidal composition comprising: a pesticidal, phosphoric ester the molecule of which has at least one alkyl group of 1 to 3 carbon atoms, 0.05 to 10% of an agent stabilizing the said ester against decomposition by protonisation, together with adjuvants characterized in that the stabilizing agent comprises at least one sulphur compound containing per molecule at least one divalent sulphur atom of which one valence is bonded to an atom chosen from sulphur, carbon, nitrogen, hydrogen, and metals capable of giving a salt, the other valence being bonded to an atom chosen from hydrogen, the carbon atom already noted, a second carbon atom, the nitrogen atom already noted, a second nitrogen atom, the metal atom already noted in the case of a metal of valence greater than one, a second atom of metal and oxygen when the first valence is not attached to an atom of hydrogen, the proportion of sulphur calculated with reference to the weight of the sulphur compound being between 5 and 99%. Process for stabilizing a phosphoric ester of which the molecule possesses at least one alkyl group containing 1 to 3 carbon atoms characterized in that there is added to the phosphoric ester or to a mixture which contains it, 0.05 to 10% calculated on the weight of the phosphoric acid ester of an agent capable of stabilizing the said phosphoric ester against protonisation and comprising at least one sulphur compound such as that defined thereupon.
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