Ketones dialkylamino

The p-substituted amino ketones can be reduced readily to the more stable P-dialkylamino alcohols, many of which are useful local anaesthetics. Thus the local anaesthetic Tutocaine is made from the Mannich base derived from formaldehyde, methyl ethyl ketone and dimethylamine, followed by reduction and conversion into the p-aminobenzoate ... 

The corresponding saturated dialkylamino ketones (Mannich bases) have also been used to provide 5,6-dihydro derivatives, which are oxidized in air to aromatic pyrido[2,3-[Pg.229]

Enamino ketones can protonate not only on nitrogen or carbon but also on oxygen to give 12,13, and 14, respectively. Enamino ketones form stable perchlorates, chlorides, bromides, and iodides, and examination of their infrared (21,22), ultraviolet (23), and nuclear magnetic resonance (24,25) spectra show these salts to be O protonated. The salts of 4-dialkylamino-... 

The cyclization of 1,3,5-triketones to pyrones will not be discussed here, although this is a related reaction, because pyrones are not true pyrylium salts. Mention will be made, however, of the formation of 2,6-diphenyl-4-pyrone from 1,3-dibenzoylallene this ketone adds secondary amines leading to 3-dialkylamino-l,5-diphenyl-4-penten-l,5-diones, which arc cyclized by hydrogen chloride in acetic acid to 2,6-diphenyl-4-dialkylaminopyrylium chlorides (R = Me and/or Ph) (see Scheme. 5). 

Thus, ynaminoketones with 1,2-diaminobenzene form benzodiazepines with retention of the dialkylamino group. The reaction occurs as a nucleophilic addition in the absence of catalysts. With Q, /3-acetylenic ketones 1,2-diaminobenzene reacts in the same manner, but under proton-catalyzed conditions (72LA24). At the same time, ynamines and enynamines furnish with 1,2-diaminobenzene substituted benzimidazoles as aresultof double attack at the acetylene bond(83ZOR926 84ZOR1648). 

Certain ketoximes can be converted to nitriles by the action of proton or Lewis acids. Among these are oximes of a-diketones (illustrated above), a-keto acids, a-dialkylamino ketones, a-hydroxy ketones, p-keto ethers, and similar compounds. These are fragmentation reactions, analogous to 17-25 and 17-26. For example, ot-dialkylamino ketoximes also give amines and aldehydes or ketones besides nitriles. 

Scheme 9.18 Ru-catalysed reductions of ketones with (r 6-arene)-Af-perfluorosulfonyl-1,2-diamine and Af-(Af,Af-dialkylamino)sulfamoyl-l,2-diamine ligands.

The general method for the preparation of diphenylpyrazolines is shown in Scheme 11.8, in which X is a suitable leaving group, usually chloro but sometimes dialkylamino. This reaction normally proceeds readily, although pH control may be important. Preparation of the substituted ketone and hydrazine intermediates needed for the synthesis may involve lengthy and complicated sequences. Further reactions are often required to modify the substitution in ring B after formation of the pyrazoline ring. The preparation of compound 11.26 shown in Scheme 11.9 illustrates one of the simpler instances. 

A useful method for obtaining indazoles in high yields involves treatment of ortho-azido phenyl ketones or aldehydes with hydrazine hydrate. When this reaction was applied to 3-azido-2-formylselenophene, selenolo[3,2-c] pyrazole (111) was obtained in low yield. The yield could not be improved when the amino derivative was prepared as an intermediate142 (Scheme 13). 2-Dialkylamino-5-formylselenophenes react with diazonium salts under deformylation conditions to give azo dyes (Eq. 39).143 Another nitrogen-containing derivative of selenophene is compound U2.144 ... 

Individual aspects of nitrile oxide cycloaddition reactions were the subjects of some reviews (161 — 164). These aspects are as follows preparation of 5-hetero-substituted 4-methylene-4,5-dihydroisoxazoles by nitrile oxide cycloadditions to properly chosen dipolarophiles and reactivity of these isoxazolines (161), 1,3-dipolar cycloaddition reactions of isothiazol-3(2//)-one 1,1-dioxides, 3-alkoxy- and 3-(dialkylamino)isothiazole 1,1-dioxides with nitrile oxides (162), preparation of 4,5-dihydroisoxazoles via cycloaddition reactions of nitrile oxides with alkenes and subsequent conversion to a, 3-unsaturated ketones (163), and [2 + 3] cycloaddition reactions of nitroalkenes with aromatic nitrile oxides (164). 

The reactions of a-bromoalkyl nitrones (298) with secondary amines lead initially to a-dialkylamino derivatives (432), which on heating, give aldehydes and ketones (75a,b) in high yield (Scheme 2.205) (540). 

If a C=C bond is formally substituted for C=N, the reaction could proceed analogously however, it would require accessible aminoacety-lenes. Reagents of this type exist (e.g., N,N-diethylpropin-l-amine 79), and react with a,/l-unsaturated ketones 26 without a catalyst in inert solvents (73JHC165). This is a convenient approach toward 2-N,N-dialkylamino-4H-pyrans 80 and 81, which are formed, probably, via the hetero-Dieh-Alder reaction (Scheme 22). 

Die Anwendung dieser Methode auf cyclische a-Methylen-ketone mit dem Grundgeriist von Diterpen-alkaloiden liefert die entsprechenden a-(Dialkylamino-methyl)-ketone in guten Ausbeuten1. 

Reaction of tris(dialkylamino)boranes with ketones to give enamines [163]. 

Quite unique is the formation of a-A,A-dialkylamino ketones from aldehydes and dialkylamines (Eq. (62) Table 4, No. 50)... 

TEBA).248 This reaction could not be applied to aliphatic nitriles, but an indirect method for achieving this conversion is given in 9-57. ot-Dialkylamino nitriles can be converted to ketones R2C(NMe2)CN —> R2C=0] by hydrolysis with CuS04 in aqueous methanol24 or by autoxidation in the presence of r-BuOK.250... 

Diacetyl-D-erythronolactone, 112 Dialkylaminoallenes, 432 a-Dialkylamino ketones, 299 Dialkylboranes, 261, 262... 

Alkyltrisidialkylamino)titanium derivatives, R Ti(NR2)3. ) These reagents are readily available by reaction of halotris(dialkylamino)titanium with organolithium or -magnesium compounds. The reagents, prepared in situ in ether, react with nonenolizable aldehydes to give tertiary amines (1), possibly via an iminium salt (equation I). With enolizable aldehydes and ketones, the reaction results in enamines after nonaqueous workup. 

Polyphenylsilane, (PhSiH) , can be derivatized by free-radical hydrosilylation in the presence of a radical initiator. Alkenes, ketones and aldehydes react readily, to replace up to 93% of the Si-H bonds. This route can be employed to make polysilanes with hydrophilic groups, such as hydroxy, amino and carboxylic acid functions.43 Dialkylamino substituted polysilanes, made by the anionic polymerization of masked disilenes (see equation (17)), when treated with acetyl chloride give chloro-substituted poly silanes. The chlorine can then be displaced by other nucleophiles.27... 

As shown in the previous section, N-alkyl nitroanilines 23 are obtained in the reaction of pyridone 1 with ketones 22 in the presence of amines. In this case, amines are introduced as the dialkylamino substituents. On the contrary, different reactivity is observed when ammonia is used instead of amines. The TCRT reaction proceeds to afford 2,3-dialkyl-5-nitropyridines 24 upon treatment of pyridone 1 with ketones 22 in the presence of ammonia (Table 2) [42,43]. The C4 - C5 - C6 unit is derived from pyridone 1, the C2 - C3 unit is derived from ketone, and the ring nitrogen (Nl) is from ammonia, namely the new ring consists of three components. As electrophilic nitration of pyridines is quite difficult, the present TCRT will be an alternative method for preparation of nitropyridine derivatives. 

Among C(R)-substituted ferrocenes, various derivatives, containing cyano, amino, dialkylamino, amino(dialkylamino)methyl, azide, aldehyde, ketone, rhodanide, and... 

Lithium enolates of phenyl esters (28) react with aldehydes or ketones to give O-lithiated phenyl 3-hydroxyalkanoates (29) which undergo spontaneous intramolecular cyclization to P-lactones (30) (95JOC758), Also, lithium enolates are used in the synthesis of 3-[l-(dialkylamino)alkyl]()-lactoncs (94JOC7994), which are precursors for a-oxo-P-lactones. 

J. H. Brewster, E. L. Eliel, Carbon-Carbon Alkylations with Amines and Ammonium Salts , Org. React. 1953, 7, 99-197 [covers Michael Additions Starting from /3-(Dialkylamino) ketones, -esters or Nitriles],... 

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