ChemInform Abstract: Mild and Direct Access to 7‐Substituted‐4‐trifluoromethylpyrimido[1,2‐b]pyridazin‐2‐one Systems.

Abstract

Mild and Direct Access to 7-Substituted-4-trifluoromethylpyrimido[1,2-b]pyridazin-2-one Systems. -Aniline and diisopropylamine are found to be unreactive in the transformation with (VI). The reaction of (I) to (VIIIa) or (Xb) or (XIIa), resp., is also performed following a one-pot procedure giving virtually equal yields of products. -(PETRIGNET, J.; THIERY, E.; SILPA, L.; ABARBRI*, M.; Synthesis 46 (2014) 7, 947-954, http://dx.doi.org/10.1055/s-0033-1340664 ; Lab. Infect. Sante Publique, Fac. Sci. Tech., Univ. Francois-Rabelais, F-37200 Tours, Fr.; Eng.) -F. Schill 38-175

Simple and Expedient Access to Novel Fluorinated Thiazolo- and Oxazolo[3,2-a]pyrimidin-7-one Derivatives and Their Functionalization via Palladium-Catalyzed Reactions

“…Continuing our interest in the development of efficient methods for the synthesis of new fluorinated heterocyclic compounds with possible biological properties [41][42][43][44][45][46][47], we Classically, Thiazolo and oxazolo[3,2-a]pyrimidin-7-one derivatives have been synthesized by reactions of the corresponding 2-aminoazoles with a symmetric alkyne such as dialkyl acetylenedicarboxylates [28][29][30][31][32][33][34][35][36] (Figure 2a), or an asymmetric alkyne such as ethyl propiolate derivatives [37][38][39][40] (Figure 2b). However, despite their relevance, these procedures have several drawbacks such as a lack of generality, poor regioselectivity, the use of expensive reagents or less available reagents, as well as unsatisfactory yields.…”

“…Continuing our interest in the development of efficient methods for the synthesis of new fluorinated heterocyclic compounds with possible biological properties [41][42][43][44][45][46][47], we Despite the numerous approaches described in the literature for the synthesis of nonfluorinated thiazolo-or oxazolo[3,2-a]pyrimidin-7-one derivatives, the incorporation of fluorinated groups into these scaffolds has never been reported to date. Thus, the development of a simple and efficient method using readily available starting materials to access new fluorinated thiazolo-and oxazolo[3,2-a]pyrimidin-7-one derivatives is highly desired.…”

“…Continuing our interest in the development of efficient methods for the synthesis of new fluorinated heterocyclic compounds with possible biological properties [41][42][43][44][45][46][47], we report here a simple and regioselective synthesis of a novel series of fluorinated thiazolo and oxazolo[3,2-a]pyrimidin-7-one derivatives, by [3+3] cyclocondensation of 2-aminothiazoles or 2-amino-oxazoles with fluorinated alkynoates (Figure 2c). This simple synthetic strategy, which relies on the use of easily prepared fluorinated alkynoates [48] and of commercially available 2-aminothiazoles and oxazoles, represents a highly efficient one-step route and regioselective access to fluorinated thiazolo-and oxazolo[3,2-a]pyrimidin-7-ones.…”

Efficient Access to 3,5-Disubstituted 7-(Trifluoromethyl)pyrazolo[1,5-a]pyrimidines Involving SNAr and Suzuki Cross-Coupling Reactions

“…Recently, we described the condensation of 5-substituted 3-aminopyrazoles with ethyl 4,4,4-trifluoro-2-butynoate, affording regioselectively the 2-substituted 7-(trifluoromethyl)pyrazolo [1,5-a]pyrimidin-5-ones in fair to good yields [37]. Continuing our research directed towards the development of new heterocyclic compounds containing the fluorine atoms [38][39][40][41], we report herein an efficient approach for synthesizing 3,5-disubstituted 7-(trifluoromethyl)pyrazolo [1,5-a]pyrimidines in good yields through S N Ar and Suzuki-Miyaura cross-coupling reactions, using 3-bromo-7-(trifluoromethyl)pyrazolo [1,5-a]pyrimidin-5-one as a starting material.…”