Synthesis of [(3S,5R)-3-Hydroxy-5-methylpiperidin-1-yl](2-methylpyridin-3-yl)methanone

Russian Journal of Organic Chemistry - There remain challenges for effectively synthesizing heterocycles containing both piperidine and pyridine rings, mainly due to the inefficient synthetic...     

2,5-二甲氧基-4-[(1E)-2-(1H-苯并咪唑-2-基)乙烯基]苯甲醛的合成

以2-甲基苯并咪唑(1)和2,5-二甲氧基-1,4-对苯二甲醛(3)为原料,经缩合反应合成了新化合物——2,5-二甲氧基-4-[(1E) -2-( 1H-苯并咪唑-2-基)乙烯基]苯甲醛(4),其结构经1H NMR,IR和ESI-MS表征.较佳缩合反应条件为:1 11 mol,n(1)∶n(3)=1.1∶1.0,回流反应6h,收率75.2％.     

Straightforward Synthesis of 2-(1H-Pyrazol-4-yl)-1H-benzimidazoles

Russian Journal of Organic Chemistry - One-pot condensation of pyrazole-4-carbaldehydes with o-phenylenediamine in the presence of chloro(trimethyl)silane (pyridine, 90°C, ambient air)...     

Synthesis of Quinolone Analogues: 7-[(2S,4R)-2-Aminomethyl-4- hydroxypyrrolidin-1-yl] Quinolones

Quinolone antibacterial agents have emerged as one of the dominant classes chemotherapeutic drugs for the treatment of various bacterial infections1. We have focused our attention on the modification of the C-7 basic group of the quinolone which has been most varied. In 1987, Uno et al.2 reported that 3-hydroxypyrrolidine quinolones showed more active antibacterial activities than Norfloxacin in vivo. In 1998, Fujita et al.3 reported that 2-aminomethylpyrrolidine quinolones have the same …     

Highly enantioselective addition of dimethylzinc to arylaldehydes catalyzed by (2S)-1-ferrocenyl-methylaziridin-2-yl(diphenyl)methanol

Asymmetric addition of dimethylzinc to a wide variety of aromatic aldehydes is described in the presence of a catalytic amount of chiral β-amino alcohol [(2S)-1-ferrocenyl- methylaziridin-2-yl(diphenyl)methanol], and a reaction enantioselectivity of up to 97.5% ee was achieved in this transformation in the absence of additional metals such as Ti or Ni. The results showed that this particular addition reaction, characterized by the lower reactivity of dimethylzinc with aldehydes, was more sensitive to structural variations in substrate aldehydes than the corresponding diethylzinc addition. A possible transition state for the catalytic asymmetric addition has been proposed on the basis of previous studies.     

Synthesis of N-methyl-N-[(1S)-1-[(3R)-pyrrolidin-3-yl]ethyl]amine

N-Methyl-N-[(1S)-1-[(3R)-pyrrolidin-3-yl]ethyl]amine (1)(1) is a key intermediate in the preparation of premafloxacin (2), which was under development as an antibiotic for use against pathogens of veterinary importance. This paper describes the development of a practical, efficient, and stereoselective process for the preparation of 1 from isobutyl (3S)-3-[methyl[(1S)-1-phenylethyl]amino]butanoate (5c). The key steps in the synthetic sequence are an asymmetric Michael addition, which yields 5c, and a stereoselective alkylation, which yields (3S,4S)-3-allyl-1,4-dimethylazetidin-2-one (17).     

Recyclization of 2-(3,6-diaryl-2,5-dihydropyridazin-4-yl)-1H-benzimidazoles to 2-[(3,5-diarylpyrazol-4-yl)methyl]-1H-benzimidazoles

2-(3,6-Diaryl-2,5-dihydropyridazin-4-yl)-1H-benzimidazoles undergo a previously unknown type of recyclization of the pyridazine ring to a pyrazole to give 2-[(3,5-diarylpyrazol-4-yl)methyl]-1H-benzimidazoles. It is suggested that the mechanism of this conversion, which includes formation of a secondary enhydrazine group in the diazine ring and its subsequent contraction, occurs after the intramolecular formation and opening of a cyclopropane ring. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 853–861, June, 2008.