1- Amino-3-pentanone

There also exists an acidregioselective condensation of the aldol type, namely the Mannich reaction (B. Reichert, 1959 H. Hellmann, 1960 see also p. 291f.). The condensation of secondary amines with aldehydes yields Immonium salts, which react with ketones to give 3-amino ketones (=Mannich bases). Ketones with two enolizable CHj-groupings may form 1,5-diamino-3-pentanones, but monosubstitution products can always be obtained in high yield. Unsymmetrical ketones react preferentially at the most highly substituted carbon atom. Sterical hindrance can reverse this regioselectivity. Thermal elimination of amines leads to the a,)3-unsaturated ketone. Another efficient pathway to vinyl ketones starts with the addition of terminal alkynes to immonium salts. On mercury(ll) catalyzed hydration the product is converted to the Mannich base (H. Smith, 1964). 

Primary amines form Schiff bases, (CH3 )2C=NR. Ammonia induces an aldol condensation followed by 1,4-addition of ammonia to produce diacetone amine (from mesityl oxide), 4-amino-4-methyl-2-pentanone [625-04-7] (CH2)2C(NH2)CH2COCH2, and triacetone amine (from phorone),... 

Reaction of the chiral (45,5R)-oxazolidine 9. obtained from 3-pentanone and (-)-2-amino-l-phenylpropanol, with aldehydes gives predominantly a H -aldol adducts of high enantiomeric purity. The corresponding spn-adducts, formed in low enantiomeric excess, are isolated from the diaslereomeric mixture by chromatography 5. 

At this temperature 4-(dimethylamino)-3,3-dimethyl-2-butanone, which is formed initially, isomerizes to l-(dimethyl-amino)-4-methyl-3-pentanone. 

The less highly substituted Mannich bases can also be prepared directly from ketones and dimethyl(methylene)ammonium trifluoroacetate by the procedure reported here, which takes advantage of the isomerization of Mannich bases in trifluoroacetic acid. (In acetic acid the Mannich bases undergo elimination of dimethylamine to give a-methylene ketones.) This method is rapid and affords products having an isomeric purity of at least 90% without difficult separations. The 49-57% yield of l-(di-methylamino)-4-methyl-3-pentanone obtained with this procedure compares favorably with the overall yields of amino ketones prepared by the indirect routes mentioned previously. 

This method, an adaptation of a previously described procedure,2- 8-4 has been used with a variety of amino acids and anhydrides to give the following products 1-phenyl-1-propionamidO-2-butanone (75%) 6 acetamidoacetylacetone (60%) 6 N-methyl-acetamidoacetone 6 l-phenyl-2-acetamido-3-butanone (79%) 7 l-phenyl-2-propionamido-3-pentanone (41%) 7 l-phenyl-2-butyr-amido-3-hexanone (27%) 7 a-benzamidopropiophenone (42%) 7 a-benzamido-/3-phenylpropiophenone (44%) 7 1 -phenyl-1 -aceta-midoacetone (72-90%) 8-91-phenyl-1-benzamidoacetone (65%) 8 l-phenyl-2-benzamido-3-butanone (78%) 8 3-benzamido-2-buta-none (65-88%) 8 and 3-acetamido-5-methyl-2-hexanone (73%).10... 

Trimethyl(prop-l-en-2-yloxy)silane afforded (3-amino ketone 24u in good yield (Table 5, entry 10). Silyl enol ethers derived from 3-pentanone and cyclopentanone smoothly afforded (3-amino ketones 24v and 24w, respectively (Table 5, entries 11 and 12). Tetrasubstituted silyl enol ethers readily produced the expected products 24x and 24g (Table 5, entries 13 and 14). 

The construction of a quaternary a-stereocenters was demonstrated in the 117-catalyzed Mannich addition [72] of methylcyclo-pentanone-2-carboxylate to N-Boc-protected aromatic aldimines and furnished the adducts 1-3 in 70-97% yield, with good ee values (85-87%) and diastereoselectivities (Scheme 6.115). The authors exemplified the synthetic utility of the protocol by a simple racemization-free decarboxylation of the Mannich adduct of N-Boc benzaldimine and dimethyl malonate to obtain the respective N-Boc-protected p-amino ester (68% yield/89%... 

Nitromcthyl-2-penten2 860 mg (10 mmol) 3-Pentanon, 2,44 g (40 mmol) Nitro-methan, 1 -3 mmol Amin-Katalysator (Piporidin/Amino-eyclohexan/1,2-Bis-[dimethylamino]-ethan/l,2-Diamino-cthan) und 25 ml Benzol werden 21 h zum RtickfluB erhitzt. Es wird destillativ aufgearbeitet Sdp. 81 °/l 7 Torr (2,3 kPa) Ausbeute ... 

Unter Aufnahme von molekularem Stickstoff und Bildung von Amino-Gruppen aus die-sem Stickstoff verlauft die Umsetzung von in situ erzeugtem Titanocen mit sauerstoff-freiem Stickstoff und (danach) z. B. 3-Pentanon nach der Hydrolyse erhalt man ein 2 1-Gemisch von 3-Amino-pentan und Bis-[]-ethyl-propyl]-amin in 25-50%iger Ausbeute (bez. auf aufgenommenen Stickstoff)2 ... 

The procedure reported here provides a convenient method for the a-hydroxylation of ketones which form enolates under the reaction conditions. The reaction has been applied successfully to a series of para-substituted acetophenones, 1-phenyl-1-propanone, 3-pentanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclododecanone, 2-methyl cyclohexanone, 2-norbornanone and benzalacetone. In the case of a steroidal example it was shown that a carbon-carbon double bond and a secondary hydroxyl group are not oxidized. A primary amino function, as in the case of p-aminoacetophenone, is not affected.5 Similarly, a tertiary amino ketone such as tropinone undergoes the a-hydroxy at ion reaction.5... 

ANTIBIOTICS - BETA-LACTAMS - MONOBACTAMS] (Vol 3) 4-Amino-4-methyl-2-pentanone [625-04-7]... 

Cl2N4O2C 3H30, 3-Pentanone, 2-[[3-[[2-(hydroxy imino)-1, l -dimethyl propyl] amino]propyl]amino]-, oxime, dihydrochloride, [104484-57-3], 31 273... 

Enolizable ketones were converted directly into their a-hydroxy dimethyl acetals upon reaction with DIB and methanolic potassium hydroxide at room temperature. If, during work up, there was acid treatment, then a-hydroxyketones were directly obtained. Numerous examples are known for such transformation, e.g. with 3-pentanone, acetophenones, 2,6-diacetylpyridine [16], tropan-3-one [17], -amino-ketones of great structural variety [18], etc. even a free radical reacted successfully in this way [19]. This conversion for an acetyl-oxazole served for the preparation of pyrimidine derivatives. 

C23H30Oy, 23637-79-8) sec Gestrinone cis-l-ethyl-l-(2-hydroxy-2-ethoxycarhonylethyl)-l,23,4,6,7,12,12b-octahydroindolo 23-o]quinolizine (C22Hk,N20, 43184-10-7) see Vinburnine 5- ethyI(2-hydroxyethyl)amino]-2-pentanone (C,2Hh,N02 74509-79-8) see Hydroxychloroquine 7-ethyl-3-(2-hydroxyethyl)indole (Ci2H,5NO 41340-36-7) see Etodolac... 

Tetramethyl-3-piperideine (35) may be prepared from mesityl oxide via diacetoneamine (4-amino-4-methyl-2-pentanone) and reaction with acetaldehyde to give 2,2,6-trimethyl-4-piperidone, which is then treated with methylmagnesium iodide and dehydrated.28... 

Aliphatic and aryl aliphatic amino ketones are made by the amination of the halogenated carbonyl compounds, - e.g., dimethylaminoacetone (74%), l-diethylamino-2-pentanone (79%), and a-methylaminopropio-phenone (57%). It is noteworthy that this system may undergo a rearrangement, viz., ArCOCH,Br+ (C,H,),NH— ArCHjCON(C,H5)a (45%). The reaction of a-halo ketones with arylamines is even more complex. Examples of the formation of a-aminoaldehydes by this method are few. However, the same results may be achieved by the amination of the halo acetals with subsequent hydrolysis. "... 

This reaction is analogous to the preparation of bis(4-imino-2-pentanonato)copper(II) [bis(4-amino-3-penten-2-onato)copper(II)] described by Holtzclaw, Collman, and Alire, and it consists in mixing an ethanolic solution of the -keto imine ( -imino ketone) with an ammoniacal metal salt solution. Advantages of this technique are the simplicity of preparation and the fact that acetylacetone imide (4-imino-2-pentanone) can be purchased. The product is useful as a starting material in ligand-exchange reactions. 

C6H13CI 2-chloro-4-methylpentane 25346-32-1 386.15 32.975 1,2 8764 C6H13NO 4-amino-4-methyl-2-pentanone 625-04-7 467.43 40.764 ... 

REGIOSELECTIVE MANNICH CONDENSATION WITH DIMETHYL(METHYLENE)AMMONIUM TRIFLUOROACETATE 1-DIMETHYL AMINO-4-METHYL-3-PENTANONE... 

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