Piperazinone derivative

In a similar way, piperazinone derivatives can be prepared by either addition of the formed amine to a carboxylate moiety or by an intramolecular alkylation with a chloromethyl group present in the substrate [485]. 

The synthesis of bicyclic y-lactam-piperazinone derivatives has been reported by Hulme et al. [8b] as an extension of the UDC strategy. Alternatively, the formation of y-lactams by reacting y-keto acids, amines, and isocyanides [89] has been ex-... 

Reaction of 4-A-benzyl piperazinone derivatives with Lawesson s reagent resulted in isomerization (Scheme 80). ... 

Figure 4.5 Rate constants for the cleavage kd, 393 K, open symbols) and the reformation ka 373 K, closed S5mbols) of various piperazinone derived alkoxyamines in a semilogarithmic plot vs. the steric substituent constant...

Scheme 47 Piperazinone ring by /V-a-methoxylation of a proline derivative.

The preparation of derivatives of this ring system has also been achieved by reaction of substituted piperazines with urea. Reaction of the starting piperazinone (284) with urea under fusion conditions gives the desired ring system (285) (66CPB194). 

The use of diamine derivatives in the three-component process leads to peptidomimetic heterocycles, such as 2-oxopiperazines (piperazinones) [58], benzopiperazi-nones [58] and benzodiazepines. In fact, the 2-oxopiperazines 89 can be obtained directly in one step via the reaction of a diamine 85 with glyoxylic acid 86 and a boronic acid 87 (Scheme 7.12) [58]. Presumably, the intermediate amino acids 88 can undergo a subsequent boronic acid-catalyzed lactamization [29] to afford 89. A two-step approach was used for the synthesis of benzopiperazinones (e.g. 96) [58]. 

Boger DL, Goldberg J, Satoh S, Ambroise Y, Cohen SB, Vogt PK, Non-amide based combinatorial libraries derived from N-Boc iminodiacetic acid Solution-phase synthesis of piperazinone libraries with activity against LEF-l//l-catenin-mediated transcription, Helv. Chim. Acta, 83 1825-1845, 2000. 

The properties of hindered diazacycloalkanones were evaluated as light stabilizers and antioxidants for polypropylene. A totally hindered piperazinone was found to be excellent light stabilizer with many other desirable properties as a polymer additive. Partially hindered decahydroquinoxalinone derivatives were found to be surprisingly good antioxidants. The relationship between structure parameters and activity was investigated. 

Takeda have recently described [93] the piperazinone TAK-029 (49), which was derived from the weak lead (50) (IC50 1 lOOnM), which was itself... 

Up to my knowledge, only commercial HALSs that are not based on TAA derivatives are the piperazinone types (e.g., LMW-HALS-2). Their synthesis is more complicated (see Scheme 17.10). 

Nitrogen containing heterocycles can he reduced by NaBH3CN under acidic conditions. Two recent examples involved the stereoselective reduction of pyrazines to piperazines (eq 43) and pyrazinones to piperazinones (eq 44). The effectiveness of the ongoing use of sodium cyanoborohydride in reduction of cyclic imine derivatives was demonstrated by these reactions. In both cases only a single diastereomer of product was detected and isolated. 

In addition to the above, a number of other heterocyclic compounds, for example, 2-aroylbenzofurans, 1,3-benzoxathioles, dihydropyrans, 1,4-benzoxazines, hydantoin derivatives, piperazine-2,5-diones, thioethenes, 1-arylbenzimidazoles, benzofuran-1-oxides, piperazinones, thiazoles, 5-thiacyclohexanecarboxaldehyde, pyrroles, triazines, fused napthoquinone derivatives and P-lactams have been synthesised using PTC technique." ... 

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