The synthesis of various new 1-aminated-2,5-cyclohexadienes is described. These reagents can be used in radical transfer hydroaminations of unactivated and electron-rich double bonds. With thiols as polarity reversal catalysts good yields are obtained. The radical hydroamination occurs with good to excellent anti-Markovnikov selectivity. Many functional groups such as alcohols, silyl ethers, phosphonates
Synthesis of Carbamates from Amines and Dialkyl Carbonates: Influence of Leaving and Entering Groups
作者:Pietro Tundo、C. McElroy、Fabio Aricò
DOI:10.1055/s-0029-1219927
日期:2010.6
A number of carbamates were synthesised through a halogen-free process by reacting amines with symmetrical and unsymmetrical carbonates. The results obtained showed a specific trend of preferred leaving groups (in the dialkyl carbonates) depending on whether a catalyst or a base was used. On the other hand, investigations conducted on the preferred entering groups (amines) for the synthesis of carbamates showed the same trend regardless of whether a catalyst or a base was used. Finally, in accordance with the results obtained, it was possible to synthesise sterically hindered carbamates in high yield by transesterification of methyl carbamate with a sterically hindered alcohol.
Use as catalyst for forming urethanes,of fluorinated and of trivalent metal acid salts, composition containing same and methods using same
申请人:——
公开号:US20040044242A1
公开(公告)日:2004-03-04
The invention concerns a novel catalyst for forming urethanes. Said catalyst is characterized by the general formula: MY
3−q
[Z]
q
, wherein: Z is the radical corresponding to the anion of a super acid whereof the Hamett constant is at least equal to 13 and advantageously more than 13, M representing a trivalent metal, preferably known for forming Lewis acids; Y is an anion or a monovalent anionic function; and q is an integer selected advantageously between 1 and 3, inclusively. The invention is applicable to paint.
The synthesis of alkyl carbamates from primary aliphatic amines and dialkyl carbonates in supercritical carbon dioxide
作者:Maurizio Selva、Pietro Tundo、Alvise Perosa
DOI:10.1016/s0040-4039(01)02390-5
日期:2002.2
130°C and in the presence of compressed CO2, primary aliphatic amines [RNH2, R=C10H21, C8H17, cHex, 1-(C10H7)CH2] react with organic carbonates (R′OCO2R; R′=Me, Et) to give alkyl carbamates (RNHCO2R′, 1). Although CO2 promotes the reaction also at a low pressure, good yields (∼80%) of 1 are achievable only with supercritical carbondioxide (scCO2) at 90 bar, which inhibits the formation of N-methylated
在130°C且存在压缩CO 2的情况下,伯脂肪族胺[RNH 2,R = C 10 H 21,C 8 H 17,cHex,1-(C 10 H 7)CH 2 ]与有机碳酸酯( R′OCO 2 R; R′= Me,Et)得到氨基甲酸烷基酯(RNHCO 2 R′,1)。尽管CO 2在低压下也能促进反应,但仅在90 bar的超临界二氧化碳(scCO 2)的情况下,才能达到1的良好收率(〜80%),这会抑制N-甲基化副产物的形成。
Method for producing carbamates and method for producing isocyanates
申请人:——
公开号:US20030125579A1
公开(公告)日:2003-07-03
A method for producing carbamates that enables carbamates to be produced at low costs, with high selectivity and high yield, and in a simple manner, and a method for producing isocyanates that enables isocyanates industrially used to be produced by using the carbamates obtained by the carbamates producing method. Nonaromatic amine selected from the group consisting of aliphatic amine, alicyclic amine, and aralkyl amine is allowed to react with alkylaryl carbonate to thereby produce carbamates. Also, the carbamates thus obtained are thermally decomposed to thereby produce isocyanates. When carbamates are produced in this method, alkyl carbamates can be obtained with high selectivity and at high yield by using simple equipment. Also, when isocyanates are produced in this method, polyisocyanates used industrially as the raw material of polyurethane can be produced in a simple manner and with efficiency.