Design, synthesis and antihistaminic (H(1)) activity of some condensed 3-aminopyrimidin-4(3H)-ones

New Inhibition Detection Method to Evaluate the Human Salivary Alphaamylase Activity of Some Drugs, Molecular Docking, and SAR Studies

BACKGROUND

For the first time, the investigation of six anti-inflammatory drugs and six antihistaminic drugs for inhibitory activities against alpha-amylase has been evaluated using a new inhibition detection method in order to find new treatments for some diseases caused by α-amylase.

OBJECTIVE

The first part of this work was devoted to the evaluation of the inhibition activity of these drugs on salivary α-amylase in vitro. Then to study the nature of interactions and structure-activity relationship, using the Autodockvina program for molecular docking.

MATERIALS AND METHODS

The evaluation of the inhibitory activity of our drugs is achieved using a new method that has proved its sensitivity, quickness, and effectiveness.

RESULTS

The results of this study show that betamethasone and loratadine are potent α-amylase inhibitors with IC50 values 0.7mg/ml and 1.03 mg/ml, respectively compared to acarbose with IC50=5.6 μg/ml.

CONCLUSION

The results showed that the loratadine and the betamethasone have a strong potential to inhibit the alpha-amylase.

An efficient synthesis of 3-alkyl-2-diversity-substituted benzofuro[3,2-d]pyrimidin-4(3H)-one derivatives

Benzofuro[3,2- d]pyrimidine derivatives are prepared using aza-Wittig reactions of iminophosphoranes with n-butyl isocyanate at 40–50 °C to give carbodiimide intermediates, which are reacted with nitrogen-oxygen-containing nucleophiles to give 3-alkyl-2-amino (aryloxy/alkoxy)-benzofuro[3,2- d]pyrimidin-4(3 H)-ones in satisfactory yields in the presence of a catalytic amount of sodium ethoxide or K2CO3. The iminophosphorane also reacts directly with excess carbon disulfide, followed by n-propylamine; further reaction with alkyl halides or halogenated aliphatic esters in the presence of anhydrous K2CO3 produces the corresponding 2-alkylthio-3-n-propyl-benzofuro[3,2- d]pyrimidin-4(3 H)-ones in good yields. Their structures of the products are confirmed by 1H NMR, 13C NMR, mass spectrometry, infrared and elemental analysis.

Identification of thienopyridine carboxamides as selective binders of HIV-1 trans Activation Response (TAR) and Rev Response Element (RRE) RNAs

Small organic molecules that can selectively bind to RNA with specificity are relatively rare. Here we report the synthesis, biochemical and structural studies of thienopyridine carboxamide derivatives with the capacity of selectively recognizing and binding with HIV-1 TAR and RRE RNAs that are essential elements for viral replication.

Synthesis and Pharmacological Activities of Pyrano[2,3-d]pyrimidine and Pyrano[2,3-d]pyrimidine-5-one Derivatives as New Fused Heterocyclic Systems

Various fused oxazine such as 4-(4-methoxyphenyl)-3,7-dimethyl-1,4-dihydro-5H-pyrazolo [4′,3′:5,6]pyrano[2,3-d][1,3]oxazin-5-one2has been prepared and utilized as a starting material for novel pyrazolopyranopyrimidinones3,5,6, and7a–cand pyrazolopyranopyrimidines4,9,10, and11which are expected to possess considerable chemical and pharmacological activities. The structures of the new compounds have been elucidated by spectroscopic data and elemental analysis. The antioxidant and anticancer activities of synthesized products have been evaluated.

Regioselectively Controlled Synthesis of N-Substituted (Trifluoromethyl)pyrimidin-2(1H)-ones

A simple and regioselectively controlled method for the preparation of both 1,4- and 1,6-regioisomers of 1-substituted 4(6)-trifluoromethyl-pyrimidin-2(1H)-ones is described. Both regioisomers were synthesized from the cyclocondensation reaction of 4-substituted 1,1,1-trifluoro-4-methoxybut-3-en-2-ones: with nonsymmetric ureas for the 1-substituted 4-(trifluoromethyl)pyrimidin-2(1H)-ones (1,4-isomer) and with nonsymmetric 1-substituted 2-methylisothiourea sulfates for the synthesis of 1-substituted 6-(trifluoromethyl)pyrimidin-2(1H)-ones (1,6-isomer). Each method furnished only the respective isomer in very good yields. The structure of the products was assigned based on the (1)H and (13)C NMR as well as 2D HMBC spectral analysis.

Facile synthesis and herbicidal evaluation of 4H-3,1-benzoxazin-4-ones and 3H-quinazolin-4-ones with 2-phenoxymethyl substituents

Series of 4H-3,1-benzoxazin-4-ones and 3H-quinazolin-4-ones with phenoxy-methyl substituents were rationally designed and easily synthesized via one-pot N-acylation/ring closure reactions of anthranilic acids with 2-phenoxyacetyl chlorides to yield the 4H-3,1-benzoxazin-4-ones, and subsequently substituted with amino derivatives to obtain the 3H-quinazolin-4-ones. The herbicidal evaluation was performed on the model plants barnyard grass (a monocotyledon) and rape (a dicotyledon), and most of the title compounds displayed high levels of phytotoxicity. The active substructure and inhibitory phenotype analysis indicated that these compounds could be attributed to the class of plant hormone inhibitors. A docking study of several representative compounds with the hormone receptor TIR1 revealed an appreciable conformational match in the active site, implicating these compounds are potential lead hits targeting this receptor.

Synthesis and anticonvulsant activity of some quinazolin-4-(3H)-one derivatives

A number of 3-substituted-2-(substituted-phenoxymethyl) quinazolin-4(3H)-one derivatives have been synthesized. Their structures have been elucidated on the basis of elemental analyses and spectroscopic studies (IR, ¹H-NMR, MS). A preliminary evaluation of the anticonvulsant properties of the prepared compounds has indicated that some of them exhibit moderate to significant activity, compared to a diazepam standard.

A facile synthesis and fungicidal activities of 2-(alkylamino)-5,6-dimethylthieno[2,3-d]pyrimidin-4(3H)-ones

The aza-Wittig reactions of iminophosphorane 3 with aromatic isocyanates generated carbodiimides 4, which were reacted with alkylamines under mild conditions to give a series of 2-(alkylamino)-5,6-dimethylthieno[2,3-d]pyrimidin-4(3H)-ones 6 and 8 in satisfactory yield. Their structures were confirmed by ¹H NMR, EI-MS, IR and elementary analysis, and compound 8c was further analyzed by single-crystal X-ray diffraction. The preliminary bioassays indicated that these compounds showed excellent fungicidal activities against six kinds of fungi.

The Dimroth Rearrangement: Synthesis and Interconversion of Isomeric Triazolothienopyrimidines

Triazolo-thieno[3,2- e]pyrimidines obtained by cyclisation of 4-hydrazino-2-(methylthio)thieno[2,3- d]pyrimidine with formic acid, acetic acid, cyanogen bromide and carbon disulfide, and by oxidation of the derived aldehyde hydrazones, are found to be the triazolo[4,3- c] isomers. These [4,3- c] compounds resist isomerisation in acid, but they undergo Dimroth rearrangement to the [1,5- c] isomers under basic conditions. The crystal structure of one such rearranged product, 5-methoxy-8,9,10,11-tetrahydro[1]benzothieno[3,2- e][1,2,4]triazolo[1,5- c]pyrimidine (13b) was confirmed by X-ray analysis.

Synthesis of Thieno[2,3-d]pyrimidin-2-ylmethanamine Combinatorial Library with Four Diversity Points

The parallel solution-phase synthesis of more than 230 substituted thieno[2,3-d]pyrimidin-2-ylmethanamines has been accomplished. This strategy is based on the cyclization of 2-aminothiophen-3-carboxylates with chloroacetonitrile to construct the thieno[2,3-d]pyrimidine core with two diversity points. Derivatization of the active chlorine and functionalization of C-4 position of the pyrimidine ring allow the introduction of other diversity points. The products containing ester groups at the 6-position of the thieno[2,3-d]pyrimidine were used in amide synthesis. Simple manual techniques for parallel reactions, coupled with simple purification procedures, gave highly pure final products. The scope and limitations of the approach are discussed.

Application of Bis(iminophosphorane) in Heterocyclic Synthesis: New Entries to Symmetrically or Unsymmetrically Substituted Thieno[2,3-d:5,4-d‘]dipyrimidine-4,5(3H,6H)-diones

The bis(carbodiimides) 4, obtained from bis-aza-Wittig reactions of bis(iminophosphorane) 3 with 2 equiv of aromatic isocyanates, were reacted with secondary amine to give symmetrically substituted 2,7-diaminothieno[2,3-d:5,4-d']dipyrimidine-4,5(3H,6H)-dione 6 in the presence of a catalytic amount of EtO(-)Na(+). Reactions of 4 with phenols or ROH in the presence of a catalytic amount of potassium carbonate or RO(-)Na(+) gave symmetrically substituted 2,7-diaryl(alkyl)oxythieno[2,3-d:5,4-d']dipyrimidine-4,5(3H,6H)-diones 6 in satisfactory yields. However, iminophosphoranes 9 were obtained via reaction of bis(iminophosphorane) 3 with 1 equiv of aromatic isocyanate and subsequent reaction with an amine in the presence of a catalytic amount of EtO(-)Na(+). Further reaction of iminophosphoranes 9 with aromatic isocyanates and various nucleophile generated unsymmetrically substituted thieno[2,3-d:5,4-d']dipyrimidine-4,5(3H,6H)-diones 12 in good yields.