2869-25-2

This paper describes the development and mechanistic studies of a general, high-yielding amine Cα-H cyanation protocol via photoredox catalysis. Inexpensive NaCN is employed as the cyanide source and air is the external oxidant, resulting in mild and highly functional group tolerant conditions. Notably, efficient Cα-H cyanations of secondary and tertiary aliphatic amines and of complex, biologically active compounds (drugs) can be performed using the established methodology. Mechanistic studies suggest that the carboxylic acid additive has three effects: formation of a stabilizing hemiaminal intermediate, prevention of catalyst decomposition by protonating the substrate, and modulation of fluorescence quenching of the photoexcited catalyst species.

N-Vinylformamide (VFA), the simplest member of the enamide group, is the key compound in the synthesis of linear cationic polymers with primary amino groups. In recent decades VFA has been the object of intensive research activity in industry and in universities with the aim of developing an economic method of synthesis. The various principles underlying the synthesis are described and the possibilities for their industrial realisation are discussed. From the large number of methods two variants have now been established as industrial production procedures at BASF and Mitsubishi Kasei Corp. (MKC). VFA is now available in tonne quantities in high purity. An overview of the versatile reaction possibilities of this multifunctional monomer and an extensive list of references are also given. The radical polymerisation to polyvinylformamides and their further reaction to polyvinylamines are not covered in this review.

This invention relates to a process for the coproduction of propanediamines and alkylated aminopropanediamines. The process contemplates an initial cyanoethylation of ammonia under conditions for producing aminopropionitrile and modest levels of iminobispropionitrile. After separation of the iminobispropionitrile from the aminopropionitrile, the process involves the catalytic reductive alkylation of the iminobispropionitrile by reaction with an aldehyde in the presence of hydrogen to form the alkylated iminobispropionitrile followed by the catalytic hydrogenation of the nitrile group in aminopropionnitrile and iminobispropionitrile to the amine.

Chemistry of α-Aminonitriles I: Introduction and Pathways to Uroporphyrinogen-octanitriles.An introduction to experimental studies on the chemistry of α-aminonitriles potentially relevant to the problems of prebiotic chemistry is presented.The framework of conditions wherein the investigations is chosen to be carried out implies both molecular oxygen and - whenever feasible - water to be excluded from reaction conditions.This study focusses on 2-amino-2-propenenitrile (3) (Scheme 6) as central starting material of reaction sequences which aim at the nitrile forms of proteinogenic amino acids as well as at the aza forms of building blocks of biological cofactor molecules as their targets (Scheme 5).Schemes 13, 16, 23 as well as 25, and 26 summarize reaction sequences by which 3 is tranformed within the definied framework of conditions into the thermodynamic (statistically controlled) mixture of the four isomeric uroporphyrinogen-octanitriles 57-60.HPLC's of such mixtures document the dominance of the least symmetrical isomer whose constitutional pattern of peripheral substituents happens to be the one present in all biological porphinoids.Preparative procedures for the synthesis of 3 (Scheme 9), the β,β-disubstututed pyrrol-nitriles 30, 53, and 54 (Scheme 19) as well as the porphyrinogen-octakis(propionitrile) and -octakis(acetonitrile) 65 and 66, respectively (Scheme 24) are given.

The Bucherer-Bergs reaction provides an important tool for the synthesis of α-aminoacids and is the basis of an industrial process for producing methionine.The key compound is the α-aminonitrile 1 which leads to partial decomposition in carbonate buffer as well as in weakly basic aqueous media and to the equilibrated formation of the basic intermediate α-carboxy-aminonitrile 2a.The parameters which control the stability of 2a are summarised.These equlibria are established through an initial fast step which is then followed by the formation of the hydantoin 5a.At a constant pH this formation is first order in α-carboxyaminonitrile 2a via a 5-imino-2-oxazolidinone 3a and an α-isocyanatamide 4a.A comparison of the reactivity of 1 with that of the N-alkylated compouds 7 shows that the rate determining step of the hydantoin formation is the cyclisation of 2a at pH9.But at higher pH, the reaction is controlled by the fast partitioning of the cyclic intermediate 3a between the α-carboxyaminonitrile 2a and the isocyanatamide 4a.This study permits the direct comparison between two mechanism for the synthesis of the racemic α-aminoacids: the Bucherer-Bergs way and the catalytic hydratation of α-aminonitriles.It is clear that carbonic anhydre can be considered as a special carbonyl compound with respect to its reactivity towards α-aminonitriles.

The determination of the structure of the intermediate in the Bucherer-Bergs reaction (the transformation in aqueous solution of an aldehyde into the corresponding amino-acid via the hydantoin) showed that this reaction involved the formation of α-aminonitrile carbamate.The slow formation of the carbonic anhydride from the carbonate buffer limited the formation of that main intermediate which was in equilibrium with the α-aminonitrile.The variation of the stability of the carbamate vs pH is mainly determined by the concentration of CO2 dissolved in the mixture, but also by the equilibrated formation of products formed by the degradation of α-aminonitrile, i.e. the aminodinitrile and the cyanohydrin.