Asymmetric 1,3-Dipolar Cycloaddition Reactions

Chem. Pharm. Bull.(オピニオン)

Recent developments in the chemistry of enaminones

Synthesis of heterocycles from alkyl 3-(dimethylamino)propenoates and related enaminones.

Compounds, pharmaceuticals, kits and methods are provided for use with DPP-IV and other S9 proteases that comprise a compound comprising: 
wherein M is N or CR 4 ; Q 1 and Q 2 are each independently selected from the group consisting of CO, SO, SO 2 , and C═NR 9 ; and each L, X, R 1 , R 2 , and R 3 are as defined herein.

Dipeptidyl peptidase inhibitors

Functionalized Enamines in the Synthesis of Some Heterocyclic Compounds

Thermal transformations of 3-azido-4H-quinolizin-4-ones 4a,b and 3-azido-4H-azino[1,2–x]pyrimidin-4-ones 4c,d, available from the corresponding heteroarylamines 2a–d, were studied. The reaction products were mostly dependent on the solvent. Thus, heating of 3-azido-1-cyano-4H-quinolizin-4-one (4a) in toluene afforded 2-(pyridin-2-yl)fumaronitrile 5a, whereas 3-amino-1-cyano-4H-quinolizin-4-one (8) was obtained on treatment of 4a in a mixture of toluene and trifluoroacetic anhydride. However, heating of 4a in acetic anhydride and in acetic acid resulted in a ring contraction to produce 3-(diacetylamino)indolizine-1-carbonitrile 6a and 3-(acetylamino)indolizine-1-carbonitrile 7a, respectively. Similarly, ring contractions took place on heating ethyl 3-azido-4-oxo-4H-quinolizin-1-carboxylate 4b and 3-azido-4H-azino[1,2–x]pyrimidin-4-ones 4c,d in acetic anhydride or acetic acid to produce the N-acetylated 3-aminoindolizine derivatives 6b, 7b and 3-aminoimidazo[1,2–x]azine derivatives 6c,d in 30–89% yields. The structures of compounds 5–8 were determined by NMR spectroscopy and X-ray diffraction.

Ring Contractions of 3-Azido-4H-quinolizin-4-ones and 3-Azido-4H-azino[1,2-x]pyrimidin-4-ones : a Novel Approach to 3-Aminoindolizines and their Aza Analogues

A simple stereoselective one pot conversion of compounds with a dimethylaminomethylene group into enol esters

Eleven (S)-1,6-dialkylpiperazine-2,5-diones and five (3S,6S)-1,3,6-trialkylpiperazine-2,5-diones were prepared in three steps from the corresponding (S)-α-amino acid esters comprising of reductive N-alkylation, N-acylation and cyclisation. The synthesis of (S)-1,6-dialkylpiperazine-2,5-diones has a broad scope allowing preparation of diketopiperazines with primary and secondary alkyl groups at N(1), while the synthesis of (3S,6S)-1,3,6-trialkylpiperazine-2,5-diones is limited to compounds with primary alkyl groups at N(1). Reductive alkylation of amino acid ester hydrochlorides by catalytic hydrogenation in the presence of a carbonyl compound proved to be a simple, efficient and general method for the preparation of stable (storable) α-alkylamino acid ester hydrochlorides. The structures of the novel compounds were determined by NMR and X-ray diffraction.

Branko Stanovnik

Papers

Functionalized Enamines in the Synthesis of Some Heterocyclic Compounds

Ring Contractions of 3-Azido-4H-quinolizin-4-ones and 3-Azido-4H-azino[1,2-x]pyrimidin-4-ones : a Novel Approach to 3-Aminoindolizines and their Aza Analogues

A simple stereoselective one pot conversion of compounds with a dimethylaminomethylene group into enol esters

Synthesis and structure of novel (S)-1,6-dialkylpiperazine-2,5-diones and (3S,6S)-1,3,6-trialkylpiperazine-2,5-diones

The synthesis and transformations of some 3-thiocarbamoylthiazolidines†