ABSTRACT
The synthesis of pyrrolidin-5-one-2-carboxamides 6a-p has been developed via a one-pot Ugi reaction of allenic acids, primary amines, isocyanides, and aldehydes followed by regioselective cyclization of the resultant N-substituted-2-allenamides with KOt-Bu at room temperature. The cyclization reaction was carried out through a 5-exo-dig approach, which resulted in good yields and high atom-economy under transition-metal-free and mild reaction conditions.
ABSTRACT
In this study, an efficient multicomponent one-pot route is described for the DABCO-catalyzed synthesis of tetrazolo[1,5-a]pyrimidines. This synthesis strategy is based on the reaction of malononitrile and aldehydes with 5-aminotetrazole monohydrate using 1,4-diazabicyclo[2.2.2]octane (DABCO) in i-PrOH under reflux conditions. This protocol is a simple, green, and low-cost technique to prepare new compounds with potential medicinal properties.
Subject(s)
Piperazines/chemistry , Pyrimidines/chemistry , Pyrimidines/chemical synthesis , Tetrazoles/chemistry , Catalysis , Chemistry Techniques, SyntheticABSTRACT
The applications of [Formula: see text]-tetrabromobenzene-1,3-disulfonamide [TBBDA], poly(N-bromo-N-ethyl-benzene-1,3-disulfonamide) [PBBS], [Formula: see text]-tetrachlorobenzene-1,3-disulfonamide [TCBDA], and poly(N-chloro-N-ethyl-benzene-1,3-disulfonamide) [PCBS] as novel reagents for the preparation of spirocyclopropylbarbiturates from 2-arylidenemalononitriles and barbituric acids are described. In addition, an effective and simple domino procedure for the synthesis of 3-substituted-1,1,2,2-tetracyanocyclopropanes from carbonyl compounds and malononitrile in a one-pot manner is reported. These reactions involve Michael addition, halogenation, and intramolecular ring-closing (MHIRC) reaction sequences. We have developed an efficient procedure for the synthesis of spirocyclopropylbarbiturates and 3-substituted-1,1,2,2-tetracyanocyclopropanes using TBBDA, PBBS, TCBDA, and PCBS as new reagents.