Ring closure reactionsRing closure reactions O 0130 N-Bridgehead Heterocyclic Compounds Thenoly-Substituted. Part 2. Azaindolizines. -Quaternary salts of diazines, such as (I) and (IV) react with activated acetylenic compounds (II) in the presence of an epoxide to give the corresponding anellated products (III) and (V), respectively. -(GEORGESCU, E. I.; GEORGESCU, F.; ROIBU, C.; IUHAS, P. C.; DRAGHICI, C. C.; CAPROIU, M. T.; Rev. Roum. Chim. 47 (2002) 8-9, 885-891; S.C. OLTCHIM Res. Cent., RO-1000 Ramnicu-Valcea, Rom.; Eng.) -M. Paetzel 36-038
By the reaction of quinazoline with ω-bromo-2-acethylthiophene in methanol followed by treatment of the intermediate mixture of quaternary salts with unsymmetrical activated alkynes in propenoxide, 3-(2-thienoyl)pyrrolo[1,2-c]quinazoline derivatives were obtained. 3-(2-Thienoyl)-pyrrolo[1,2-c]quinazolines were also obtained by an alternative one-pot procedure directly from quinazoline, ω-bromo-2-acetylthiophene and unsymmetrical activated alkynes in propenoxide, by one-pot, multi-step sequences of reactions. Heating the same mixture of quinazolinium salts in the presence of the strong base 1-(2-thienoyl)-2-(2-thienyl)pyrrolo[1,2-c]quinazoline, an interesting inactivation product of the intermediate quinazolinium-3-thienoylmethylide was obtained.
N-Bridgehead Heterocyclic Compounds Thenoyl-Substituted. Part 1. Indolizines and Benzoindolizines. -The quaternization of pyridines (I) with bromoacetylthiophene (II) affords N-methylthenoyl quaternary salts (III), which undergo 1,3-dipolar cycloaddition reactions with activated acetylenic compounds in the presence of an epoxide, as acid acceptor and reaction solvent, furnishing novel thenoyl-substituted indolizines [cf. (V), (VI)]. -(GEORGESCU, EMILIAN I.; GEORGESCU, FLORENTINA; ROIBU, CON-STANTIN; DRAGHICI, CONSTANTIN C.; CAPROIU, MIRON T.; Rev.
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