Efficient synthesis and biological evaluation of 1,2,9-trisubstituted 1,9-dihydro-6H-purin-6-ones

Synthesis and anticancer activity of ethyl 5-amino-1-N-substituted-imidazole-4-carboxylate building blocks

A series of 5-amino-1-N-substituted-imidazole-4-carboxylate building blocks was synthesized and assayed for their antiproliferative potential against human cancer cell lines, including HeLa (cervical), HT-29, HCT-15 (colon), A549 (lung), and MDA-MB-231 (breast) cells. The preliminary screening results revealed that several derivatives containing alkyl chains at the N-1 position of the imidazole core demonstrate a certain inhibitory effect on growth and proliferation. A significant effect was observed following ethyl 5-amino-1-dodecyl-1H-imidazole-4-carboxylate (5e) treatment for 72 h. The IC₅₀ value for HeLa cells was 0.737 ± 0.05 μM, whereas that for HT-29 cells was 1.194 ± 0.02 μM. Further investigations revealed that 5e significantly inhibited tumor cell colony formation and migration, and it exhibited antiadhesive effects on HeLa cells as well as antitubulin activity along with the induction of early apoptosis of HeLa and HT-29 cells. In addition, derivative 5e significantly reduced the cell mitochondrial membrane potential in a dose-dependent manner and induced early apoptosis of HeLa and HT-29 cells, indicating that 5e may serve as a lead compound for further drug discovery and development.

Sequential three-component synthesis of 1,4-bis[6,9-dihydro-6-oxo-9-phenyl-1H-purin-2-yl]piperazines

A simple one-pot efficient method for the synthesis of 1,4-bis[6,9-dihydro-6-oxo-9-phenyl-1 H-purin-2-yl]piperazines by a domino three-component process involves an aza-Wittig reaction/heterocyclisation in the presence of sodium ethoxide as catalyst. Ethyl 1-phenyl-5-[(triphenylphosphoranylidene)amino]-1H-imidazole-4-carboxylate reacted with aromatic isocyanate to give carbodiimide intermediates, followed by addition of piperazines to give the corresponding guanidine intermediates. The guanidine intermediates were cyclised in the presence of a catalytic amount of sodium ethoxide to give 1,4-bis(6,9-dihydro-6-oxo-9-phenyl-1 H-purin-2-yl)piperazine derivatives in good yields.

7-Benzyl-3-(4-fluoro-phen-yl)-2-propyl-amino-5,6,7,8-tetra-hydro-pyrido[4',3':4,5]thieno[2,3-d]pyrimidin-4(3H)-one

In the title compound, C₂₅H₂₅FN₄OS, the thienopyrimidine fused-ring system is close to planar (r.m.s. deviation = 0.0089 Å), with a maximum deviation of 0.0261 (17) Å for the N atom adjacent to the benzene ring. This thienopyrimidine fused-ring system forms dihedral angles of 64.73 (3) and 81.56 (5)° with the adjacent benzyl and fluoro­phenyl rings, respectively. Inter­molecular N—H⋯F and C—H⋯F hydrogen bonding, as well as C—F⋯π inter­actions [F⋯centroid = 3.449 (3) Å; C—F⋯centroid = 91.87 (15)°], help to stabilize the crystal structure.

7-Benzyl-3-(4-chloro-phen-yl)-2-isobutyl-amino-5,6,7,8-tetra-hydro-pyrido[4',3':4,5]thieno[2,3-d]pyrimidin-4(3H)-one

In the title compound, C(26)H(27)ClN(4)OS, the thienopyrimidine fused-ring system is close to coplanar (r.m.s. deviation = 0.0089 Å), with a maximum deviation of 0.0283 (17) Å for the N atom adjacent to the benzene ring. This ring system forms dihedral angles of 83.51 (3) and 88.20 (5)° with the adjacent benzyl and phenyl rings, respectively. In the crystal, N-H⋯Cl inter-actions and C-H⋯O hydrogen bonds are observed.

6-Benzyl-2-[(triphenyl-λ-phosphanyl-idene)amino]-4,5,6,7-tetra-hydro-thieno[2,3-c]pyridine-3-carbonitrile

In the title compound, C(33)H(28)N(3)PS, the P atom has a distorted tetra-hedral PNC(3) environment, formed by the N atom and three aryl rings. No inter-molecular hydrogen-bonding inter-actions or π-π stacking inter-actions are present in the crystal structure.

7-Benzyl-3-(4-fluoro-phen-yl)-2-(pyrrol-idin-1-yl)-5,6,7,8-tetra-hydro-pyrido[4',3':4,5]thieno[2,3-d]pyrimidin-4(3H)-one

In the title compound, C₂₆H₂₅FN₄OS, the thienopyrimidine fused-ring system is close to planar (r.m.s. deviation = 0.066 Å), with a maximum deviation of 0.1243 (17) Å for the N atom adjacent to the carbonyl group. This ring system forms dihedral angles of 67.5 (1) and 88.9 (1) ° with the adjacent six-membered rings. Inter­molecular C—H⋯O hydrogen bonding and C—H⋯π inter­actions help to stabilize the crystal structure.

7-Benzyl-2-[(cyclo-propyl-meth-yl)amino]-3-phenyl-5,6,7,8-tetra-hydro-pyrido[4',3':4,5]thieno[2,3-d]pyrimidin-4(3H)-one

There are two independent mol-ecules in the asymmetric unit of the title compound, C(26)H(26)N(4)OS. In each mol-ecule, the thienopyrimidine fused-ring system is essentially planar with a maximum deviation of 0.0409 (18) for the N atom. In one mol-ecule, this ring system forms diherdral angles of 84.8 (1) and 67.6 (1)° with the adjacent phenyl and benzyl rings, respectively, while the corresponding angles in the other mol-ecule are 77.9 (1) and 66.5 (1)°.

Unexpected synthesis of indolo[1,2-c]quinazolines by a sequential Ugi 4CC-Staudinger-aza-Wittig-nucleophilic addition reaction

A new sequential Ugi-Staudinger-aza-Wittig-nucleophilic addition reaction was developed to construct indolo[1,2-c]quinazoline derivatives, starting from the easily accessible 2-azidobenzaldehyde, carboxylic acid, 2-acylaniline and isocyanide. It is noteworthy that this is the first report of the cyclization of the Ugi adduct to give a dihydroindole ring system with two quaternary carbon centers, via the nucleophilic addition reaction of the methine group to the carbonyl group.

Efficient synthesis and biological evaluation of some 2,4-diamino-furo[2,3-d]pyrimidine derivatives

The carbodiimides 2, obtained from aza-Wittig reactions of iminophosphorane 1 with aromatic isocyanates, reacted with ammonia to give ethyl 3,4-dihydro-6-methyl-4-oxo-2-arylamino-furo[2,3-d]pyrimidine-5-carboxylate 3. Further reaction of 3 with POCl(3) and various amines generated ethyl 4-alkylamino-2-arylamino-6-methyl-furo[2,3-d]pyrimidine-5-carboxylate 5 in good yields. Their structures were confirmed by (1)H NMR, EI-Ms, IR and elemental analysis. Compound 5b was further analyzed by single crystal X-ray diffraction. Compound 5 exhibited cytotoxicity against two lung cancer cell lines. For example, compound 5a showed the best inhibition activities against A459 with IC(50) 0.8μM.

Rapid and efficient synthesis of 4(3H)-quinazolinones under ultrasonic irradiation using silica-supported Preyssler nanoparticles

A new synthesis of 4(3H)-quinazolinone from the reaction of 2-amino-benzamide, and acylchlorides in the presence of catalytic amounts of silica-supported Preyssler nano particles as green, reusable and efficient catalyst under ultra sonic irradiation is reported.