Search

Twenty-five diverse pyrazolo [3,4-d]-4,5-dihydropyrimidines were synthesized in 73-91 % yield through TMS-promoted [5+1] heterocyclization of aldehydes with pyrazolylamidines. [ABSTRACT FROM AUTHOR]

Thirteen 5-hetarylarninopyrazoles were synthesized in 62--93% yield through the arylation of 1-isopropyl- and l-phenyi-5-aminopyrazoles with electrophihc hetarylhalides under optimized conditions. Condensation of 5-hetarylaminopyrazoIes with carbonyl compounds facilitated by AcOH or Me3SiCl furnished 23 pyrazolo[3,4-d]dihydropyrimidines in 69--86% yield. The target compounds were isolated through simple crystallization. The scope and limitation of the method are discussed. [ABSTRACT FROM AUTHOR]

Abstract: New efficient one-pot methodology for the preparative synthesis of β-imidazolylpropionamides was elaborated. It is based on the addition of imidazole to the activated double bond of the intermediate acrylimidazolide in the reaction between diverse acrylic acids and different amines promoted by CDI. A set of structurally and functionally diverse β-imidazolylpropionamides was obtained in high preparative yields. [Copyright &y& Elsevier]

1‐Azaspiro[3.3]heptanes were synthesized, characterized, and validated biologically as bioisosteres of piperidine. The key synthesis step was thermal [2+2] cycloaddition between endocyclic alkenes and the Graf isocyanate, ClO2S−NCO, to give spirocyclic β‐lactams. Reduction of the β‐lactam ring with alane produced 1‐azaspiro[3.3]heptanes. Incorporation of this core into the anesthetic drug bupivacaine instead of the piperidine fragment resulted in a new patent‐free analogue with high activity. [ABSTRACT FROM AUTHOR]

1‐Azaspiro[3.3]heptanes were synthesized, characterized, and validated biologically as bioisosteres of piperidine. The key synthesis step was thermal [2+2] cycloaddition between endocyclic alkenes and the Graf isocyanate, ClO2S−NCO, to give spirocyclic β‐lactams. Reduction of the β‐lactam ring with alane produced 1‐azaspiro[3.3]heptanes. Incorporation of this core into the anesthetic drug bupivacaine instead of the piperidine fragment resulted in a new patent‐free analogue with high activity. [ABSTRACT FROM AUTHOR]

Highlights: [•] First substituted pyrazolo[3,4-d]-4,5-dihydropyrimidin-6-ones are reported. [•] The compounds are prepared by a new two-step procedure from commercial chemicals. [•] Up to four different groups are introduced into the title scaffold (19 examples). [•] Both, intermediates and the title species are easily purified by crystallization. [•] The reported method is suitable for the parallel synthesis of the title structures. [ABSTRACT FROM AUTHOR]

Chemical formulas explaining the synthesis of pyrazole [3,4-d]-4,5-dihydropyrimidin-6-ones are presented.

More than twenty pyrazolodihydropyrimidine derivatives are prepared through condensation of secondary amidines with aromatic aldehydes in the presence of TmsCl as activator for the CO-group and water scavenger. [ABSTRACT FROM AUTHOR]

One-pot variation of Castagnoli condensation, that is, reaction of cyclic anhydrides, amines, and aldehydes, has been developed as a combinatorial approach to 1,2-disubstituted 5-oxopyrrolidine- and 6-oxopiperidine-3-carboxylic acids, as well as their benzo-analogues. Utility of the method to multigram preparation of building blocks and synthetic intermediates was also demonstrated. The final products are obtained in high yields and diastereoselectivity. The method fits well in the concept of lead-oriented synthesis; in particular, it can be used for the design of lead-like compound libraries, even if the strictest cut-offs are applied to the physicochemical properties of their members. [ABSTRACT FROM AUTHOR]

One-pot parallel synthesis of unsymmetrical aliphatic ureas was achieved with bis(2,2,2-trifluoroethyl) carbonate. The procedure worked well for both the monosubstituted and functionalized alkyl amines and required no special conditions (temperature control, order, or rate of addition). A library of 96 diverse ureas was easily synthesized. [ABSTRACT FROM AUTHOR]