Addition of Organolithium and Grignard Reagents to Pyrimidine-2(1H)-thione: Easy Access to 4-Substituted 3,4-Dihydropyrimidine-2(1H)-thiones

Synthesis of 3,4-Dihydropyrimidin(thio)one Containing Scaffold: Biginelli-like Reactions

The interest in 3,4-dihydropyrimidine-2(1H)-(thio)ones is increasing every day, mainly due to their paramount biological relevance. The Biginelli reaction is the classical approach to reaching these scaffolds, although the product diversity suffers from some limitations. In order to overcome these restrictions, two main approaches have been devised. The first one involves the modification of the conventional components of the Biginelli reaction and the second one refers to the postmodification of the Biginelli products. Both strategies have been extensively revised in this manuscript. Regarding the first one, initially, the modification of one of the components was covered. Although examples of modifications of the three of them were described, by far the modification of the keto ester counterpart was the most popular approach, and a wide variety of different enolizable carbonylic compounds were used; moreover, changes in two or the three components were also described, broadening the substitution of the final dihydropyrimidines. Together with these modifications, the use of Biginelli adducts as a starting point for further modification was also a very useful strategy to decorate the final heterocyclic structure.

Oxidative Dehydrosulfurative Cross-Coupling of 3,4-Dihydropyrimidine-2-thiones with Alkynes for Access to 2-Alkynylpyrimidines

A reaction method is described for the one-step synthesis of 2-alkynylpyrimidines from 3,4-dihydropyrimidin-1H-2-thiones (DHPMs) via dehydrosulfurative Sonogashira cross-coupling with concomitant oxidative dehydrogenation using a Pd/Cu catalytic system. Together with the ready availability of DHPMs possessing various substituents at the C4-C6 positions, this transformation offers rapid and general access to diverse 2-alkynylpyrimidine derivatives.

Comparative evaluation of new dihydropyrimidine and dihydropyridine derivatives perturbing mitotic spindle formation

AIM

The mitotic spindle plays a key role in cell division which makes it an important target in cancer therapy. In the present study the antiproliferative activity of 4-benzyl-5-phenyl-3,4-dihydropyrimidine-2(1H)-thione (1) and its pyridine bioisoster (2) were evaluated and compared with monastrol (MON), the first known cell-permeable small molecule which disrupts bipolar spindle formation by inhibiting Eg5-kinesin activity.

RESULTS

Our data revealed that compound 2 showed higher antiproliferative activity than MON against MCF7 and A375 cell lines and comparable reversible cell cycle inhibition in G2/M phase. However, compound 2 produced distinct phenotype from monoastral spindles, and did not affect Eg5 ATPase activity.

CONCLUSION

The activity of compound 2 may suggest its new promising anticancer mechanism (different than MON), targeting other component required for spindle bipolarity.

Regioselective synthesis of novel 4,5-diaryl functionalized 3,4-dihydropyrimidine-2(1H)-thiones via a non-Biginelli-type approach and evaluation of their in vitro anticancer activity

An easy and novel approach to synthesize 4,5-diaryl functionalized 3,4-dihydropyrimidine-2(1H)-thiones via addition of aryllithiums to 5-aryl substituted pyrimidine-2(1H)-thiones, which could be regarded as a method complementary to the most widely used Biginelli-type synthesis, is described. In the reaction of aryllithiums with N-(Me)Bn substituted pyrimidine-2(1H)-thiones a high degree of regioselectivity of addition, leading to 4-aryl adducts, was achieved. Selected compounds tested for their in vitro anticancer activity against four human cancer cell lines showed the greatest activity against breast cancer (MCF7). 1-Benzyl-4-(3-hydroxyphenyl)-5-phenyl substituted 3,4-dihydropyrimidine-2(1H)-thione (10g) exhibiting 10-fold more potent activity than the best known monastrol (MON) stands as a promising candidate for further scaffold and asymmetric synthesis.