Improved synthesis of substituted 6,7-dihydroxy-4-quinazolineamines: tandutinib, erlotinib and gefitinib

Direct methylthiolation of C-, S-, and P-nucleophiles with sodium S-methyl thiosulfate

A practical and efficient methylthiolation that employed the typical Bunte salt sodium S-methyl sulfothioate as the sulfur source was described. This reagent could react with a variety of compounds such as alkynes, 1,3-diketones, thiols, selenol and H-phosphine oxides, affording methylthiolated products in moderate to excellent yields. The advantages such as easy preparation, air- and moisture-stability and high tolerance of functional groups demonstrated the potential of this reagent to be widely applied in organic synthesis. Notably, the robustness of this reagent was demonstrated by the late-stage modification of drug molecules of erlotinib.

Globally Approved EGFR Inhibitors: Insights into Their Syntheses, Target Kinases, Biological Activities, Receptor Interactions, and Metabolism

Targeting the EGFR with small-molecule inhibitors is a confirmed valid strategy in cancer therapy. Since the FDA approval of the first EGFR-TKI, erlotinib, great efforts have been devoted to the discovery of new potent inhibitors. Until now, fourteen EGFR small-molecule inhibitors have been globally approved for the treatment of different types of cancers. Although these drugs showed high efficacy in cancer therapy, EGFR mutations have emerged as a big challenge for these drugs. In this review, we focus on the EGFR small-molecule inhibitors that have been approved for clinical uses in cancer therapy. These drugs are classified based on their chemical structures, target kinases, and pharmacological uses. The synthetic routes of these drugs are also discussed. The crystal structures of these drugs with their target kinases are also summarized and their bonding modes and interactions are visualized. Based on their binding interactions with the EGFR, these drugs are also classified into reversible and irreversible inhibitors. The cytotoxicity of these drugs against different types of cancer cell lines is also summarized. In addition, the proposed metabolic pathways and metabolites of the fourteen drugs are discussed, with a primary focus on the active and reactive metabolites. Taken together, this review highlights the syntheses, target kinases, crystal structures, binding interactions, cytotoxicity, and metabolism of the fourteen globally approved EGFR inhibitors. These data should greatly help in the design of new EGFR inhibitors.

Erlotinib

Erlotinib (OSI-774), marketed by Genentech as Tarceva®, is anticancer drug approved by US-FDA for the treatment of Non-Small Cell Lung Cancer (NSCLC) and Pancreatic Cancer. Erlotinib inhibited epidermal growth factor receptor (EGFR) that blocks tumor cell division, produces cell cycle arrest, and initiates programmed cell death in EGFR-overexpressing human tumor cells. This study presents a comprehensive profile of erlotinib, including detailed nomenclature, formula, elemental analysis, methods of preparation, physico-chemical characteristics, and methods of analysis (including spectroscopic, electrochemical, and chromatographic methods of analysis). Spectroscopic and spectrometric analyses include UV/vis spectroscopy, vibrational spectroscopy, nuclear magnetic resonance spectrometry ((1)H and (13)C NMR), and mass spectrometry. Chromatographic methods of analyses include thin layer chromatography, and high-performance liquid chromatography. Pharmacology of erlotinib including pharmacodynamics, mechanism of action, pharmacokinetics and drug-drug interactions were also presented. An appropriate table and figures were attached to each of the above mentioned sections along with total of 48 references.

Palladium catalyzed chloroethoxylation of aromatic and heteroaromatic chlorides: an orthogonal functionalization of a chloroethoxy linker

A novel disconnection based on cross-coupling chemistry was designed to access pharmaceutically relevant aryl-aminoethyl ethers. The developed palladium-catalyzed functionalization of aryl- and heteroaryl chlorides with a sodium tetrakis-(2-chloroethoxy) borate salt is orthogonal to the simple nucleophilic replacement of the chloro function of the ethylene linker. The transformation enables efficient 2-chloroethoxylation in the absence of an additional external base. Subsequent amine substitution of the alkyl halide affords 2-aminoethoxy arenes. The applicability of this method was demonstrated through the synthesis of various aryl- and heteroaryl-alkyl ethers, including the intermediates of marketed drug molecules.

Investigation of Heck coupling on 6-bromo[2,3-d]thienopyrimidines for construction of new EGFR inhibitor lead structures

With the aim of identifying new lead structures for EGFR inhibition, a study of palladium catalysed Heck coupling between (R)-6-bromo-N-(1-phenylethyl)thieno[2,3-d]pyrimidin-4-amine and various acrylates was performed.

Synthesis and evaluation of novel non-covalent binding quinazoline glycoside derivatives targeting the L858R and T790M variants of EGFR

A series of novel quinazoline glycoside derivatives were designed, synthesized, and evaluated for their inhibition activities against EGFR-WT, EGFR/L858R/T790M, and skin epidermoid carcinoma cell line (A431).

First Synthesis of Novel Aminophenyl Pyridinium-5-(hydroxybenzoyl)-hydrazonomethyl-2-oxothiazol-3-ide Derivatives and Evaluation of Their Anticancer Activities

The first total synthesis for large-scale production and anticancer activity of novel aminophenylpyridinium-5-(hydroxybenzoyl)hydrazonomethyl-2-oxothiazol-3-ide (PBHT) (1) and its derivatives are reported. The chemical structure of PBHT was unambiguously determined by utilization of the two-dimensional nuclear Overhauser effect (NOE) technique. The anticancer activity against human colon adenocarcinoma (HCT15) cells of all synthesized compounds was approximately four-fold greater than that of 5-fluorouracil, with IC50 values ranging from 10.1 to 14.2 µM. The three structural determinants of hydroxybenzoyl, hydrazinylidene, and pyridinium oxothiazole in the synthesized compounds could be indispensable for exhibiting anticancer activity.

Gefitinib

Gefitinib (Iressa®) is a selective inhibitor of epidermal growth factor, a growth factor that plays a pivotal role in the control of cell growth, apoptosis, and angiogenesis. Gefitinib is clinically used for the treatment of chemoresistant non-small cell lung cancer patients. Gefitinib is freely soluble in dimethylsulphoxide but slightly soluble in methanol and ethanol. Several methods of gefitinib synthesis are included in this review. UV spectroscopy of gefitinib showed a λmax of approximately 331nm, whereas IR spectroscopy principal peaks were observed at 3400cm(-1) (NH), 2956cm(-1) (CH2, CH, alkyl), 1625cm(-1) (CC, CN), 1500cm(-1) (HCCH, aryl), 1110cm(-1) (CO), 1028cm(-1) (CF). In addition, different analytical methods for determination of gefitinib are also described in this review. Pharmacokinetically, after oral administration, gefitinib is slowly absorbed with bioavailability of approximately 60% in human. Gefitinib is metabolized extensively in the liver into five metabolites by cytochrome P450s, primarily by CYP3A4 and to a lesser extent by CYP3A5 and CYP2D6. Gefitinib is eliminated mainly hepatically with total plasma clearance of 595mL/min after intravenous administration. Most of the adverse effects associated with gefitinib therapy are mild to moderate in severity and are usually reversible and manageable with appropriate intervention, such as diarrhea, dry skin, rash, nausea, and vomiting.

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

This review which is the second in this series summarises the most common synthetic routes as applied to the preparation of many modern pharmaceutical compounds categorised as containing a six-membered heterocyclic ring. The reported examples are based on the top retailing drug molecules combining synthetic information from both scientific journals and the wider patent literature. It is hoped that this compilation, in combination with the previously published review on five-membered rings, will form a comprehensive foundation and reference source for individuals interested in medicinal, synthetic and preparative chemistry.

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

This review which is the second in this series summarises the most common synthetic routes as applied to the preparation of many modern pharmaceutical compounds categorised as containing a six-membered heterocyclic ring. The reported examples are based on the top retailing drug molecules combining synthetic information from both scientific journals and the wider patent literature. It is hoped that this compilation, in combination with the previously published review on five-membered rings, will form a comprehensive foundation and reference source for individuals interested in medicinal, synthetic and preparative chemistry.

Design and synthesis of novel 4-benzothiazole amino quinazolines Dasatinib derivatives as potential anti-tumor agents

Three series of novel 4-benzothiazole amino quinazolines Dasatinib derivatives have been designed and synthesized. The entire target compounds were investigated for their in vitro cytotoxic activity by the MTT-based assay against 6 human cancer cell lines. Compared with the parental Dasatinib, most of the new compounds, especially 2, 4, 6-trimethylaniline series (3), demonstrated significant inhibitory activities against six cell lines. Furthermore, the target compounds were screened for Src and Abl kinase inhibitory activity. Among them, 1a, 1f and 3a-3f are more potential dual Src/Abl kinase inhibitors. Thus they may be promising lead compounds to be developed as an alternative for current Dasatinib therapy or for Imatinib-resistant patients, potentially via simultaneously blocking multiple RTK signaling pathways.

Disclosure of erlotinib as a multikinase inhibitor in pancreatic ductal adenocarcinoma

A placebo-controlled phase 3 trial demonstrated that the epidermal growth factor receptor (EGFR) inhibitor erlotinib in combination with gemcitabine was especially efficient in a pancreatic ductal adenocarcinoma (PDAC) subgroup of patients developing skin toxicity. However, EGFR expression was not predictive for response, and markers to characterize an erlotinib-responding PDAC group are currently missing. In this work, we observed high erlotinib IC50 values in a panel of human and murine PDAC cell lines. Using EGFR small interfering RNA, we detected that the erlotinib response was marginally influenced by EGFR. To find novel EGFR targets, we used an unbiased chemical proteomics approach for target identification and quality-controlled target affinity determination combined with quantitative mass spectrometry based on stable isotope labeling by amino acids in cell culture. In contrast to gefitinib, we observed a broad target profile of erlotinib in PDAC cells by quantitative proteomics. Six protein kinases bind to erlotinib with similar or higher affinity (K(d) = 0.09-0.358 µM) than the EGFR (K(d) 0.434 µM). We provide evidence that one of the novel erlotinib targets, ARG, contributes in part to the erlotinib response in a PDAC cell line. Our data show that erlotinib is a multikinase inhibitor, which can act independent of EGFR in PDAC. These findings may help to monitor future erlotinib trials in the clinic.

Design and synthesis of a series of novel bisquinazoline glycosides as epidermal growth factor receptor inhibitors

A new series of potential epidermal growth factor receptor inhibitors possessing bisquinazoline and saccharide moieties were designed and synthesized. The biological results demonstrated that the synthetic derivatives significantly inhibited epidermal growth factor receptor enzymatic activity in vitro. Of them, compound 14b showed the highest inhibitory rate toward epidermal growth factor receptor protein tyrosine kinase (81.36%) at a concentration of 1 μM. Further molecular simulation predicted that 14b offered its saccharide moieties hydrogen bonding to ATP-binding pocket.

Synergistic induction of apoptosis in brain cancer cells by targeted codelivery of siRNA and anticancer drugs

Multiple dysregulated pathways in tumors necessitate targeting multiple oncogenic elements by combining orthogonal therapeutic moieties like short-interfering RNAs (siRNA) and drug molecules in order to achieve a synergistic therapeutic effect. In this manuscript, we describe the synthesis of cyclodextrin-modified dendritic polyamines (DexAMs) and their application as a multicomponent delivery vehicle for translocating siRNA and anticancer drugs. The presence of β-cyclodextrins in our DexAMs facilitated complexation and intracellular uptake of hydrophobic anticancer drugs, suberoylanilide hydroxamic acid (SAHA) and erlotinib, whereas the cationic polyamine backbone allowed for electrostatic interaction with the negatively charged siRNA. The DexAM complexes were found to have minimal cytotoxicity over a wide range of concentrations and were found to efficiently deliver siRNA, thereby silencing the expression of targeted genes. As a proof of concept, we demonstrated that upon appropriate modification with targeting ligands, we were able to simultaneously deliver multiple payloads--siRNA against oncogenic receptor, EGFRvIII and anticancer drugs (SAHA or erlotinib)--efficiently and selectively to glioblastoma cells. Codelivery of siRNA-EGFRvIII and SAHA/erlotinib in glioblastoma cells was found to significantly inhibit cell proliferation and induce apoptosis, as compared to the individual treatments.

Design, synthesis, docking and antitumor activity of quinazolino [3, 4-a] thieno [3, 2-d] pyrimidin-8-one derivatives

Several novel quinazolino [3, 4-a] thieno [3, 2-d] pyrimidin-8-one derivatives were synthesized. All of the compounds were determined against MiaPaCa2 and DU145 cells in vitro, and the crystal structures of analog 8 and 20 in the active site of the EGFR complexes were presented. The entire compounds had been identified by 1HNMR, 13CNMR, IR, MS and EA.

Novel Preparation of gefitinib

A new synthesis of the anticancer drug gefitinib is described starting from methyl 3-hydroxy-4-methoxybenzoate. The sequence involves alkylation of the starting material, followed by nitration, reduction, cyclisation, chlorination and amination reactions. This new method has six steps, uses a much cheaper starting material and has higher yields than other methods. It is suitable for industrial production.

N-(4-Isopropoxyphenyl)acetamide

In the mol­ecule of the title compound, C₁₁H₁₅NO₂, the planar acetamide unit [maximum deviation of 0.0014 (6) Å] is oriented at a dihedral angle of 19.68 (4)° with respect to the aromatic ring. An intra­molecular C—H⋯O inter­action results in the formation of a six-membered ring. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into chains along the a axis

Methyl 2-amino-4-(3-chloropropoxy)-5-methoxybenzoate

The asymmetric unit of the title compound, C₁₂H₁₆ClNO₄, contains two crystallographically independent mol­ecules. The benzene rings of the two independent mol­ecules are oriented at a dihedral angle of 88.50 (3)°. Intra­molecular N—H⋯O hydrogen bonds involving the methoxybenzoate carbonyl group in each molecule result in the formation of two planar, six-membered rings, oriented at dihedral angles of 1.39 (3) and 0.68 (3)° with respect to the adjacent benzene rings. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into chains along the a axis.

Methyl 4-(3-chloropropoxy)-5-methoxy-2-nitrobenzoate

The asymmetric unit of the title compound, C₁₂H₁₄ClNO₆, contains two crystallographically independent mol­ecules, in which the benzene rings are oriented at a dihedral angle of 9.12 (3)°. In the crystal structure, weak inter­molecular C—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional network.

Methyl 5-methoxy-2-nitro-4-[3-(piperidin-1-yl)propoxy]benzoate

In the mol­ecule of the title compound, C₁₇H₂₄N₂O₆, the dihedral angle between the four coplanar atoms of the piperidine ring and the benzene ring is 39.2 (1)°.

Methyl 4-but-oxy-3-methoxy-benzoate

The title compound, C(13)H(18)O(4), is an inter-mediate product in the synthesis of quinazoline derivatives. Crystal structure analysis shows that the benzene-butoxy C(ar)-O-C-C torsion angle is 175.3 (2)° and that the benzene-methoxycarbonyl C(ar)-C-O-C torsion angle is 175.2 (2)°. Torsion angles close to 180° indicate that the molecule is almost planar.

Synthesis of gefitinib from methyl 3-hydroxy-4-methoxy-benzoate

This paper reports a novel synthesis of gefitinib starting from methyl 3-hydroxy-4-methoxybenzoate. The process starts with alkylation of the starting material, followed by nitration, reduction, cyclization, chlorination and two successive amination reactions. The intermediates and target molecule were characterized by 1H-NMR, 13C-NMR, MS and the purities of all these compounds were determined by HPLC. This novel synthetic route produced overall yields as high as 37.4%.