2733-51-9Relevant academic research and scientific papers
Ring Enlargement of Three-Membered Heterocycles by Treatment with In Situ Formed Tricyanomethane
Banert, Klaus,Chityala, Madhu,Korb, Marcus
supporting information, p. 6158 - 6164 (2020/05/04)
Although the chemistry of elusive tricyanomethane (cyanoform) has been studied during a period of more than 150 years, this compound has very rarely been utilized in the synthesis or modification of heterocycles. Three-membered heterocycles, such as epoxides, thiirane, aziridines, or 2H-azirines, are now treated with tricyanomethane, which is generated in situ by heating azidomethylidene-malonodinitrile in tetrahydrofuran at 45 °C or by adding sulfuric acid to potassium tricyanomethanide. This leads to ring expansion with formation of 2-(dicyanomethylidene)oxazolidine derivatives or creation of the corresponding thiazolidine, imidazolidine, or imidazoline compounds and opens up a new access to these push–pull-substituted olefinic products. The regio- and stereochemistry of the ring-enlargement processes are discussed, and the proposed reaction mechanisms were confirmed by using 15N-labeled substrates. It turns out that different mechanisms are operating; however, tricyanomethanide is always acting as a nitrogen-centered nucleophile, which is quite unusual if compared to other reactions of this species.
Regioselective synthesis of heterocyclic ketene N,N-,N,O-and N,S-acetals in aqueous medium
Chanu, Langpoklakpam Gellina,Singh, Okram Mukherjee,Jang, Sang Hun,Lee, Sang-Gyeong
experimental part, p. 859 - 862 (2010/10/21)
The reactions of ketene dithioacetals with ethane-1,2-diamine, propane-1,3-diamine, 2-aminoethanol, 3-aminopropanol, and 2-aminoethanethiol in ordinary water in the absence of any acid/base catalyst afforded the heterocyclic ketene N,N-, N,O-and N,S-aceta
Substituted 2-methylene-1,3-oxazolidines, -1,3-thiazolidines, -1,3-benzothiazines, -1,3-oxazines, and substituted imidazopyrimidinediones from Cl(CH2)nNCO and Cl(CH2)nNCS and active methylene compounds
Basheer, Ahmad,Rappoport, Zvi
, p. 9743 - 9750 (2007/10/03)
The reaction of ω-chloroalkyl isocyanates Cl(CH2) nNCO (n = 2 (2), 3 (4)) and isothiocyanate Cl(CH2) 2-NCS (3) with active methylene compounds CH2YY′ 1 in the presence of Et3N or Na give 2-YY′-methylene-1,3- oxazolidines, (E,Z)-1,3-thiazolidines, and 1,3-oxazines from 2, 3, and 4, respectively. 2-(Chloromethyl)-phenyl isocyanate 8 gives with 1 the corresponding benzo-oxazines. Ethyl 2-isothiocyanatobenzoate 10 gives the corresponding benzothiazolinone, whereas the analogous isocyanate 12 gives noncyclic enols. Ethoxycarbonyl isothiocyanate 14 gives an open-chain thioenol or an enol-thioamide. The cyanoamides CH2(CN)CONHR, R = H, Me, CHPh2, give with Et3N and 2 the bicyclic imidazopyrimidinediones 16, derived from two molecules of 2, but with their preformed Na salt they give the 1,3-oxazolidines. Reaction of cyanoacetamide with 3 in the presence of Na gave a tricyclic triaza(thia)indacene, derived from two molecules of 3. A reaction mechanism involving an initial attack of the anion 1- on the N=C=X (X = O, S) moiety gives an anion 18, which cyclizes intramolecularly and after tautomerization gives the mono-ring heterocycle. With the cyanoamides, the N- site of the ambident ion 18 attacks another molecule of 2 giving the anion 20, which by intramolecular attack on the CN, followed by expulsion of the Cl- gives the bicyclic 16 after tautomerization.
Reaction d'imidoylation: Reactivite de composes a methylene actif avec les O-ethylcarbamates cycliques
Huche, Michel,Lhommet, Gerard
, p. 701 - 704 (2007/10/02)
Condensation of malononitrile, ethylcyanacetate and isopropylidene malonate with various O-ethyl cyclic carbamates leads to α-(tetrahydroxazole-1,3-ylidene-2) and α-(tetrahydroxazine-1,3-ylidene-2) malononitriles, ethylcyanacetates and isopropylidene malonates.
