Quinazolines annelated at the N(3)-C(4) bond: Synthesis and biological activity

This review covers article and patent data obtained mostly within the period 2013-2023 on the synthesis and biological activity of quinazolines [c]-annelated by five- and six-membered heterocycles. Pyrazolo-, benzimidazo-, triazolo- and pyrimido- [c]quinazoline systems have shown multiple potential activities against numerous targets. We highlight that most research efforts are directed to design of anticancer and antibacterial agents of azolo[c]quinazoline nature. This review emphases both on the medicinal chemistry aspects of pyrrolo[c]-, azolo[c]- and azino[c]quinazolines and comprehensive synthetic strategies of quinazolines annelated at N(3)-C(4) bond in the perspective of drug development and discovery.

Discovery of gefitinib-1,2,3-triazole derivatives against lung cancer via inducing apoptosis and inhibiting the colony formation

A series of 20 novel gefitinib derivatives incorporating the 1,2,3-triazole moiety were designed and synthesized. The synthesized compounds were evaluated for their potential anticancer activity against EGFR wild-type human non-small cell lung cancer cells (NCI-H1299, A549) and human lung adenocarcinoma cells (NCI-H1437) as non-small cell lung cancer. In comparison to gefitinib, Initial biological assessments revealed that several compounds exhibited potent anti-proliferative activity against these cancer cell lines. Notably, compounds 7a and 7j demonstrated the most pronounced effects, with an IC50 value of 3.94 ± 0.17 µmol L-1 (NCI-H1299), 3.16 ± 0.11 µmol L-1 (A549), and 1.83 ± 0.13 µmol L-1 (NCI-H1437) for 7a, and an IC50 value of 3.84 ± 0.22 µmol L-1 (NCI-H1299), 3.86 ± 0.38 µmol L-1 (A549), and 1.69 ± 0.25 µmol L-1 (NCI-H1437) for 7j. These two compounds could inhibit the colony formation and migration ability of H1299 cells, and induce apoptosis in H1299 cells. Acute toxicity experiments on mice demonstrated that compound 7a exhibited low toxicity in mice. Based on these results, it is proposed that 7a and 7j could potentially be developed as novel drugs for the treatment of lung cancer.

Synthesis and In Vitro Antitumor Activity Evaluation of Gefitinib-1,2,3-Triazole Derivatives

In this study, 14 structurally novel gefitinib-1,2,3-triazole derivatives were synthesized using a click chemistry approach and characterized by 1H NMR, 13C NMR and high-resolution mass spectrometry (HRMS). Preliminary cell counting kit-8 results showed that most of the compounds exhibit excellent antitumor activity against epidermal growth factor receptor wild-type lung cancer cells NCI-H1299, A549 and NCI-H1437. Among them, 4b and 4c showed the most prominent inhibitory effects. The half maximal inhibitory concentration (IC50) values of 4b were 4.42 ± 0.24 μM (NCI-H1299), 3.94 ± 0.01 μM (A549) and 1.56 ± 0.06 μM (NCI-1437). The IC50 values of 4c were 4.60 ± 0.18 µM (NCI-H1299), 4.00 ± 0.08 μM (A549) and 3.51 ± 0.05 μM (NCI-H1437). Furthermore, our results showed that 4b and 4c could effectively inhibit proliferation, colony formation and cell migration in a concentration-dependent manner, as well as induce apoptosis in H1299 cells. In addition, 4b and 4c exerted its anti-tumor effects by inducing cell apoptosis, upregulating the expression of cleaved-caspase 3 and cleaved-PARP and downregulating the protein levels of Bcl-2. Based on these results, it is suggested that 4b and 4c be developed as potential new drugs for lung cancer treatment.

Time-resolved spectroscopic and computational study of the initial events in doxazosin photochemistry

Doxazosin is a quinazoline derivative widely used in medicine as a drug. In this study, a combined experimental and computational approach based on the time-dependent density functional theory was used to elucidate the primary events following the photoexcitation of DOX upon interaction with light. The photophysical properties and photochemical reactivity of DOX were investigated by steady-state and time-resolved absorption and fluorescence spectroscopy. DOX in H2O in S0 is present in two prototropic forms, with the protonated form dominating (∼91 %, pKa = 6.75). The computations indicated that the most basic quinazoline nitrogen is at the position 1. Upon excitation, DOX deprotonates in the singlet excited state (pKa* = 1.31), and the decay times from the singlet excited state of 5 ns and 13 ns are attributed to the non-protonated and protonated forms of DOX, respectively. The quantum yield of fluorescence in H2O is 0.51 and 0.64 in basic media. The quantum yield of intersystem crossing along with triplet-triplet molar absorption coefficient at 520 nm and the lifetime of the triplet excited state were obtained by LFP, ΦISC = 0.17, ε520 = 11600 ± 100 M-1 cm-1 and τ = 11 μs, respectively. Furthermore, LFP enabled detection of DOX radical formed by the photoinduced intramolecular electron transfer from the benzodioxane-carbamoyl to the protonated aminoquinazoline. Computations were used to back up the assignments of the detected transients and to construct an energy diagram with all plausible photophysical and photochemical pathways. These results elucidated the mechanisms of DOX photochemistry leading to DOX photodegradation which is relevant to environmental studies. They also provided insights into the potential use of such a quinazoline derivative in other applications such as push-pull chromophores or fluorescent probes.

Synthesis and Structure-Photophysics Evaluation of 2-N-Amino-quinazolines: Small Molecule Fluorophores for Solution and Solid State

2-N-aminoquinazolines were prepared by consecutive S_N Ar functionalization. X-ray structures display the nitrogen lone pair of the 2-N-morpholino group in conjugation with the electron deficient quinazoline core and thus representing electronic push-pull systems. 2-N-aminoquinazolines show a positive solvatochromism and are fluorescent in solution and in solid state with quantum yields up to 0.73. Increase in electron donor strength of the 2-amino substituent causes a red-shift of the intramolecular charge transfer (ICT) band (300-400 nm); whereas the photoluminescence emission maxima (350-450 nm) is also red-shifted significantly along with an enhancement in photoluminescence efficiency. HOMO-LUMO energies were estimated by a combination of electrochemical and photophysical methods and correlate well to those obtained by computational methods. ICT properties are theoretically attributed to an excitation to Rydberg-MO in SAC-CI method, which can be interpreted as n-π* excitation. 7-Amino-2-N-morpholino-4-methoxyquinazoline responds to acidic conditions with significant increases in photoluminescence intensity revealing a new turn-on/off fluorescence probe.

Molecular Targeting of Epidermal Growth Factor Receptor (EGFR) and Vascular Endothelial Growth Factor Receptor (VEGFR)

Epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor (VEGFR) are two extensively studied membrane-bound receptor tyrosine kinase proteins that are frequently overexpressed in many cancers. As a result, these receptor families constitute attractive targets for imaging and therapeutic applications in the detection and treatment of cancer. This review explores the dynamic structure and structure-function relationships of these two growth factor receptors and their significance as it relates to theranostics of cancer, followed by some of the common inhibition modalities frequently employed to target EGFR and VEGFR, such as tyrosine kinase inhibitors (TKIs), antibodies, nanobodies, and peptides. A summary of the recent advances in molecular imaging techniques, including positron emission tomography (PET), single-photon emission computerized tomography (SPECT), computed tomography (CT), magnetic resonance imaging (MRI), and optical imaging (OI), and in particular, near-IR fluorescence imaging using tetrapyrrolic-based fluorophores, concludes this review.