Amino ketones, beta

Reactions have been run to make amine-group-containing lignin (121-123) and free, amine groups which can accept a proton have been quantified (118) in the lignin products. The use of amination to form commercial products of lignin requires that beta amino ketones be formed on the aliphatic chains in the polyalkylaromatic. The acid catalyzed addition of methanal and a primary or secondary amine (Mannach reaction 124) is conducted on alkali lignin in aqueous... 

Xu X, Wang C, Zhou Z, Tang X, He Z, Tang C (2007) The aza-Morita-Baylis-Hillman reaction of JV-thiophosphoryl imines catalyzed by l,3,5-triaza-7-phosphaadamantane (PTA)—convenient synthesis of alpha-methylene-beta-amino ketone or acid derivatives. Eur J Org Chem 4487-4491... 

Lauret, C. and Roberts, S. M. Asymmetric epoxidation of alpha,beta-unsaturated ketones catalyzed by poly(amino acids), Aldrichim. Acta, 2002, 35, 47-51. 

The Knorr Pyrrole Synthesis. In this process, the starting materials are an alpha-amino ketone, or less commonly an alpha-amino aldehyde, and a beta-ketoester. In the latter, the protons on the alpha carbon are activated both by the keto and the ester carbonyls and are especially easily removed. The Knorr process starts with the condensation of the amino group with the keto group in the usual way to tie the two molecules together as in 4.29 of the example shown in Scheme 4.31. This species then undergoes intramolecular aldol-type condensation to form a reduced pyrrole derivative 4.30. 

Ultimately, a complete retrosynthesis of a P-amino ketone leads to the three components needed in a Mannich reaction a ketone, an aldehyde, and an amine. The retrosynthesis of a P-amino ketone begins with making a disconnection between the alpha carbon and the carbon bearing the amino group (the beta carbon). This aldol-like disconnection leads to a nucleophilic alpha carbon (enol) and an electrophilic imine carbon (C=N). Further disconnection of the imine affords the two necessary building blocks for its formation an aldehyde and an amine. 

When Schiff s bases (242), derived from ketones and tm-butylamine, were reacted with dimethyl methoxymethylenemalonate in diphenyl ether at 80-130°C for 1-15 hr, then at 190-250°C for 1-3 hr, 2-hydroxy-3-pyridinecarboxylates (243) were obtained by a one-pot procedure. In the first step of the reaction, the beta-carbon of the enamine moiety was involved instead of the amino group (89JHC773). 

Found in processed truffles but absent in fresh truffles were two furans (compound 4 and 7) and a pyrazine (compound 24). Furans are well known to result from the thermal degradation of carbohydrates while alkyl pyrazines result from the reaction of amino acids and alpha-diketones. A number of methyl ketones were also observed in the canned product which were absent in the fresh product. Methyl ketones are known to result from the thermal decomposition of beta-keto acids (17-19) -... 

The only other beta-methyl homologue of an active material that was explored chemically, was related to MDA. The ketone (3,4-piperonylacetone, see under MDMA) was methylated with sodium isopropoxide and methyl iodide, and a crystalline oxime was obtained. Reduction with Zn dust gave what appeared to be 2-amino-3-(3,4-methylenedioxyphenyl)butane hydrochloride, but there were sufficient uncertainties (possible dimethylation, only one oxime isolated, the need of strong reducing conditions) that the entire project was placed in, and still is in, an indefinite holding pattern. The similar analogues for DOM are the two Classic Ladies, DAPHNE and ELVIRA, and they, too, are for some time in the future. 

Sawamura M, Nakayama Y, Kato T, Ito Y (1995) Gold(I)-catalyzed asymmetric aldol reaction of JV-methoxy-JV-meihyl-alpha-isocyanoacetamide (alpha-isocyano Weinreb amide)—an efBcient synthesis of optically-active beta-hydroxy-alpha-amino aldehydes and ketones. J Org Chem 60 1727-1732... 

---