Chemistry of heterocyclic ketene aminals: construction of imidazo(pyrido)[1,2-a]pyridines and imidazo(pyrido)[3,2,1-ij][1,8]naphthyridines via DABCO-catalyzed tandem annulations.
نویسندگان
چکیده
2-(2-Chloroaroyl)methyleneimidazolidines with four reactive sites show fascinating structural features and could be used as a new strategy for the synthesis of novel heterocycles. This paper presents our new findings in the reaction of 2-(2-chloroaroyl)methyleneimidazolidines with allenic esters affording functionalized imidazo(pyrido)[1,2-a]pyridines via DABCO-catalyzed tandem annulations. Of particular significance is the incorporation of an o-halo group into the aryl ring of 2-benzoylmethylene-imidazolidines to set up a convenient and general way for constructing unusual imidazo(pyrido)[3,2,1-ij][1,8]naphthyridines.
منابع مشابه
Four-component cascade heteroannulation of heterocyclic ketene aminals: synthesis of functionalized tetrahydroimidazo[1,2-a]pyridine derivatives.
An efficient and straightforward four-component synthetic protocol has been developed to synthesize imidazo[1,2-a]pyridines and imidazo[1,2,3-ij][1,8]naphthyridine derivatives incorporating medicinally privileged heterosystems from heterocyclic ketene aminals, aldehydes, diketene, and amines via cascade reactions, including diketene ring-opening, Knoevenagel condensation, aza-ene reaction, imin...
متن کاملA new rapid multicomponent domino heteroannulation of heterocyclic ketene aminals: solvent-free regioselective synthesis of functionalized benzo[g]imidazo[1,2-a]quinolinediones.
A highly efficient and straightforward three-component cascade reaction was developed to synthesize benzo[g]imidazo[1,2-a]quinolinedione derivatives from heterocyclic ketene aminals (HKAs), aldehydes, and 2-hydroxy-1,4-naphthoquinone (HNQ) via Et(3)N-catalyzed tandem [3 + 2 + 1] annulation under solvent-free conditions. The reactions were very mild, convenient and highly regioselective to form ...
متن کاملSYNTHESIS OF NOVEL HETEROCYCLIC SYSTEM 4H-IMIDAZO [ 2,l -b] PYRIDO [2,3-el [I, 3,4] THIADIGZIM
Diazotization of 3-amino-2-cMoro pyridine (3) in the presence of dithizone (5) gave dphenyl-2-phenylazo-4H-pyrid[o3 ,2-e] [1,3,4] thiadiazine (6). Reaction of 2- chloro-3-nitropyridine (2, G=H) with (5) dfordd 4-phenyl -2-phenylazo -4Hpyrido [2,3-el [1,3,4] thiadiazine (7). Reduction of the latter with H gas in the presence of Raney nickel gave the corresponding amino derivative (12). One ...
متن کامل6-Benzyl-3,4-dimethoxy-10-methylpyrido[2′,1′:2,3]imidazo[4,5-c]isoquinolin-5(6H)-one
Pyrido[2',1':2,3]imidazo[4,5-c]isoquinolin-5(6H)-ones such as the title compound, C(24)H(21)N(3)O(3), can be obtained in a few minutes in a microwave-assisted three-component reaction from 2-amino-pyridines, isocyanides and 2-carboxy-benz-aldehydes. In the title compound, the pyrido[2',1':2,3]imidazo[4,5-c]isoquinolin-5(6H)-one ring system is almost planar (mean deviation 0.068 Å). The dihedral...
متن کاملDual role of p-tosylchloride: copper-catalyzed sulfenylation and metal free methylthiolation of imidazo[1,2-a]pyridines.
Copper-catalyzed regioselective C-3 sulfenylation of imidazo[1,2-a]pyridines using p-tosylchloride as a benign source of sulfenylating agents has been developed. On the other hand, p-tosylchloride mediated thiomethylation of imidazo[1,2-a]pyridines with dimethylsulfoxide as a source of thiomethylation under metal-free conditions was also described.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- The Journal of organic chemistry
دوره 76 9 شماره
صفحات -
تاریخ انتشار 2011