78204-84-9Relevant articles and documents
Solventless selective phosgene-free N-carbonylation of N-heteroaromatics (pyrrole, indole, carbazole) under mild conditions
Carafa, Marianna,Iannone, Francesco,Mele, Valentina,Quaranta, Eugenio
, p. 3377 - 3385 (2013/01/16)
N-Heteroaromatics HetNH, such as pyrrole (1), indole (2) and carbazole (3), have been selectively N-carbonylated by a direct reaction with diphenyl carbonate (DPC), used as an environmental friendly carbonyl active species in place of toxic and hazardous phosgene. The carbonylation reaction can be effectively catalyzed by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), which can act as a base catalyst by activating the HetNH substrate, and as a nucleophile catalyst by activating the organic carbonate. The influence of reaction parameters (temperature, reaction time, DBU load, DPC/HetNH molar ratio) on the productivity of the process has been also investigated. The synthetic methodology does not require severe temperature conditions, is solventless, simple (only one step), efficient and selective, and offers a new solution to the synthesis of synthetically versatile HetNCO2Ph derivatives through a route alternative to the current traditional phosgenation methods.
DBU-promoted nucleophilic activation of carbonic acid diesters
Carafa, Marianna,Mesto, Ernesto,Quaranta, Eugenio
experimental part, p. 2458 - 2465 (2011/06/10)
The reactivity of carbonic acid diesters in the presence of the amidine base DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) has been investigated for the first time. Organic carbonates can be activated by DBU through the formation of N-alkoxycarbonyl ketene aminal 2 as the ultimate product. The latter species may form through deprotonation of the corresponding N-alkoxycarbonyl-amidinium cation 1+ by the amidine base. We have for the first time isolated and characterized, both in the solid state (X-ray crystal structure determination, IR) and in solution (NMR), a few 1+ chloride salts and studied their reactivity towards the organic base. The reactivity of both 1+ and 2 with methanol has also been explored. Ketene aminal 2 behaves as a "CO2R" carrier, as it can selectively transfer the alkoxycarbonyl group to the alcohol and regenerate the amidine base. Carbonic acid diesters can be activated by the amidine base DBU to give N-alkoxycarbonyl ketene aminal 2. The latter species may form through deprotonation of N-alkoxycarbonyl-amidinium cations 1+ by the amidine base and behave as carriers of the -C(O)OR group. Copyright
Obtention d'organochlorogermylamines stabilisees par un substituant organique chelatant: le 3-amino 2-methylthiophoate
Riviere-Baudet, M.,Riviere, P.,Castel, A.,Morere, A.,Abdennhader, C.
, p. 131 - 141 (2007/10/02)
The use of 3-amino 2-methylthiophoate allows the formation of stabilized organohalogermylamines. 3-Organochlorogermylamino 2-methylthiophoates were synthesized either by intermolecular dehydrochlorination between chlorogermanes and the amino-thiophoate in the presence of DBU or by reaction of chlorogermanes with the corresponding thiophoate lithium amide.A probable complexation between the carbonyl group of the ester function with the electrophilic germanium center is supported by spectroscopic data (IR, UV temperature 1H NMR) and can explain the enhanced reactivity of the Ge-Cl bond which allows easy synthesis of sterically hindered bis (3-amino-2-methyl thiophoates)-diorganogermanes.
