Synthesis and antimicrobial activities of a novel series of heterocyclic α-aminophosphonates.

Two series of novel α-aminophosphonates having heterocyclic moieties were synthesized in high yields. The structures of the newly synthesized compounds were confirmed by their elemental analyses, IR, (1)H NMR and MS spectral data. These compounds were screened for their antibacterial activities against Escherichia coli (NCIM2065) as a Gram-negative bacterium, Bacillus subtilis (PC1219) and Staphylococcus aureus (ATCC25292) as Gram-positive bacteria, and Candida albicans and Saccharomyces cerevisiae as fungi. The minimum inhibitory concentrations (MICs) of the synthesized compounds show high antibacterial and antifungal activities at low concentrations (10-1000 µg/mL). Furthermore, their lethal doses indicated that such compounds are safe for use as antimicrobial agents.

Synthesis, antimicrobial and anticancer activities of a novel series of diphenyl 1-(pyridin-3-yl)ethylphosphonates.

A novel series of diphenyl 1-(arylamino)-1-(pyridin-3-yl)ethylphosphonates 1-5 was obtained in high yields from reactions of 3-acetyl pyridine with aromatic amines and triphenylphosphite in the presence of lithium perchlorate as a catalyst. The structures of the synthesized compounds were confirmed by IR, (1)H NMR spectral data and microanalyses. Compounds 1-5 showed high antimicrobial activities against Escherichia coli (NCIM2065) as a Gram-negative bacterium, Bacillus subtilis (PC1219) and Staphylococcus aureus (ATCC25292) as Gram-positive bacteria and Candidaalbicans and Saccharomyces cerevisiae as fungi, at low concentrations (10-100 µg/mL). Also, the synthesized compounds showed significant cytotoxicity anticancer activities against liver carcinoma cell line (HepG2) and human breast adenocarcinoma cell line (MCF7). The lethal dose of the synthesized compounds was also determined and indicated that most compounds are safe to use.

Studies on antiretroviral drug concentrations in breast milk: validation of a liquid chromatography-tandem mass spectrometric method for the determination of 7 anti-human immunodeficiency virus medications.

Studying the pharmacokinetics of antiretroviral drugs in breast milk has important implications for the health of both the mother and the infant, particularly in resource-poor countries. Breast milk is a highly complex biological matrix, yet it is necessary to develop and validate methods in this matrix, which simultaneously measure multiple analytes, as women may be taking any number of drug combinations to combat human immunodeficiency virus infection. Here, we report a novel extraction method coupled to high-performance liquid chromatography and tandem mass spectrometry for the accurate, precise, and specific measurement of 7 antiretroviral drugs currently prescribed to infected mothers. Using 200 microL of human breast milk, simultaneous quantification of lamivudine (3TC), stavudine (d4T), zidovudine (ZDV), nevirapine (NVP), nelfinavir (NFV), ritonavir, and lopinavir was validated over the range of 10-10,000 ng/mL. Intraday accuracy and precision for all analytes were 99.3% and 5.0 %, respectively. Interday accuracy and precision were 99.4 % and 7.8%, respectively. Cross-assay validation with UV detection was performed using clinical breast milk samples, and the results of the 2 assays were in good agreement (P = 0.0001, r = 0.97). Breast milk to plasma concentration ratios for the different antiretroviral drugs were determined as follows: 3TC = 2.96, d4T = 1.73, ZDV = 1.17, NVP = 0.82, and NFV = 0.21.

Inhibition of mammalian aspartate transcarbamylase by quinazolinone derivatives.

Quinazolinone derivatives have been studied as both in vitro and in vivo inhibitors of aspartate transcarbamylase (ATCase). In vitro treatment of mammalian ATCase with four compounds revealed that they inhibited enzyme activity and that 2-phenyl-1,3-4(H)benzothiazin-4-thione was the most potent one. This compound acts as a noncompetitive inhibitor towards both aspartate and carbamoyl phosphate. The values of the inhibition constant (K(i)) indicate that this compound exerts a potent inhibitory effect upon ATCase activity. Moreover, in vivo treatment with different doses of these derivatives showed also an inhibitory effect upon ATCase, the relative activity being decreased by 40%-58% with a 1 mg dose. These data support the inhibition of ATCase by quinazolinone derivatives as a new type of inhibitor for the enzyme.

Development of a highly efficient extraction technique and specific multiplex assay for measuring antiretroviral drug concentrations in breast milk.

Understanding the pharmacology of drugs in breast milk is important for the health of both mother and baby. Current methods to measure drug concentrations in breast milk are not easily validated for precision or accuracy, primarily because of suboptimal sample clean-up. We report here an optimized clean-up method to remove both proteins and fat from milk, thereby enhancing the extraction efficiency of antiretroviral drugs. Recoveries were consistently above 91% for all drugs, demonstrating that this method successfully and reliably released drugs from fat globules. With use of 200 muL of human breast milk, an high-performance liquid chromatography/ultraviolet method for simultaneously detecting lamivudine, stavudine, zidovudine, and nevirapine was validated over the range of 20 to 20,000 ng/mL. Intra- and interday precision (average percent relative standard deviation) and accuracy (average percent deviation from nominal) was less than 3.6% and 7.5%, respectively. Intra- and interday accuracy (average percent deviation from nominal) was less than 0.25% and 1.3%, respectively. This novel method efficiently, reliably, and accurately measured antiretroviral drugs in breast milk and can be applied to any matrix containing fat and protein.

Lithiation of 3-(Acylamino)-2-unsubstituted-, 3-(Acylamino)-2-ethyl-, and 3-(Acylamino)-2-propyl-4(3H)-quinazolinones: Convenient Syntheses of More Complex Quinazolinones(1).

3-(Pivaloylamino)- and 3-(acetylamino)-4(3H)-quinazolinones react with alkyllithium reagents to give 1,2-addition products in very good yields. Lithiation takes place with LDA and is regioselective at position 2. The lithium reagents thus obtained react with a variety of electrophiles to give the corresponding substituted derivatives in very good yields. Reactions of the lithium reagents with iodine give oxidatively dimerized cyclic structures. 3-(Pivaloylamino)- and 3-(acetylamino)-2-ethyl-4(3H)-quinazolinones and 3-(pivaloylamino)- and 3-(acetylamino)-2-propyl-4(3H)-quinazolinones are lithiated at the benzylic position with LDA. The lithium reagents so produced also react with a variety of electrophiles to give the corresponding 2-substituted-4(3H)-quinazolinone derivatives in very good yields. However, lithiation of 3-(acylamino)-2-(1-methylethyl)-4(3H)-quinazolinones was unsuccessful, as were lithiations of compounds having a diacetylamino group at position 3. The amide groups have been cleaved in good yield under basic or acidic conditions from some of the products to provide access to the free amino compounds.

Lithiation of 2-Alkyl-3-amino- and 2-Alkyl-3-(methylamino)-4(3H)-quinazolinones(1).

3-Amino-2-methyl-4(3H)-quinazolinone has been doubly lithiated, on nitrogen and in the 2-methyl group, with n-butyllithium. The lithium reagent thus obtained reacts with a variety of electrophiles (D(2)O, benzophenone, cyclohexanone, cyclopentanone, acetophenone, benzaldehyde, tetraisopropylthiuram disulfide (TITD)) to give the corresponding 2-substituted derivatives in very good yields. Reactions of the dilithio reagent with 2 molar equiv of methyl iodide or phenyl isocyanate give disubstituted derivatives. Double lithiation of the 2-ethyl and 2-propyl analogues have been achieved using LDA, and subsequent reactions with most electophiles are then similar. In the reaction of the dianion of the 2-ethyl compound with TITD, deamination from position 3 takes place with the formation of the 2-substituted derivative. In reactions with prochiral ketones, the dianion of the 2-ethyl compound gives very high diastereoselectivity. Lithiation and subsequent reactions of 3-(methylamino) analogues take place in a similar manner, thus providing access to a range of substituted 3-(methylamino)-2-alkyl-4(3H)-quinazolinones by a general procedure. Lithiation of 3-(dimethylamino)-2-ethyl-4(3H)-quinazolinone did not take place under similar conditions. Lithiation of 3-amino-2-unsubstituted-4(3H)-quinazolinone was also unsuccessful.