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At least 145 records · Page 8Linked to original sources
PubMed1991

1,2-Dihydro-3,1-benzoxazin-4-one and 4-H-1,2-dihydro-pyrido-[2,3-d]-[1,3]-oxazin-4-one derivatives as potential prodrugs. Part II: Hydrolysis.

The kinetics of the spontaneous hydrolysis of the potential prodrugs 1a-1f, 2a-2g, and 3a-3e in methanol-buffer mixtures (3:7) at various pH-values was studied and a simple analytical uv-spectroscopic method was developed. The results show that most of the new potential prodrugs were very quickly reconverted to their parent drugs under these conditions. All of the potential prodrugs are very sensitive between pH 4.0 and 8.0, with half lives less than 50 min at 20 degrees C, except for compounds 1f, 2f, and 3d. Compounds 1b and 1c are so sensitive that they reconverted to their parent drug during the mixing of the stock solution and the buffer-methanol-mixture.

Hydrolysis↗
PubMed1991

1,2-Dihydro-3,1-benzoxazin-4-one and 4H-1,2-dihydro-pyrido-[2,3-d]- [1,3]-oxazin-4-one derivatives as potential prodrugs. Part III: Permeability through excised human skin in vitro.

The percutaneous permeation characteristics of 6 potential prodrugs 2-7 in comparison with their parent drug mefenamic acid (1) in vitro using excised human skin were studied. The results show that all potential prodrugs tested were at least 2.0 times as effective as mefenamic acid; compounds 2 and 7 permeated almost 5 times as quickly as mefenamic acid through excised human skin. The relations between the permeation behaviour, the RM values and the melting points were interpreted.

Humans↗
PubMed2003

Novel 6-aryl-1,4-dihydrobenzo[d]oxazine-2-thiones as potent, selective, and orally active nonsteroidal progesterone receptor agonists.

The functional activity of 6-aryl benzoxazinone-based progesterone (PR) antagonists changed to PR agonism when the 2-carbonyl group was replaced by a 2-thiocarbonyl moiety. Based on this finding novel 6-aryl benzoxazine-2-thiones were synthesized and evaluated as PR agonists in various in vitro and in vivo assays. Several analogues had sub-nanomolar in vitro potency and showed excellent oral activities in rats. Compounds 15 and 29 had similar potencies to medroxyprogesterone acetate (MPA) in the in vitro T47D alkaline phosphatase assay and in vivo rat decidualization model. In contrast to MPA, 29 was highly selective (>500-fold) for PR over glucocorticoid and androgen receptors.

Alkaline Phosphatase↗
PubMed1988

Synthesis and pharmacology of trans-4-n-propyl-3,4,4a,10b-tetrahydro-2H,5H-1-benzopyrano[4,3-b ]-1,4-oxazin-7- and -9-ols: the significance of nitrogen pKa values for central dopamine receptor activation.

The 6-oxa analogues of potent dopamine agonists, hexahydronaphthoxazines (4a,4b), have been tested for dopamine receptor binding and stimulating activity and were found to be almost inactive. pKa value determinations indicated that these compounds are protonated to approximately 2%, while potent compounds are protonated to a much greater extent. These results strongly support the assumption that the protonated form of DA agonists is the active species at the receptor.

Animals↗
PubMed2005

Synthesis and structure-activity relationship of novel 6-aryl-1,4-dihydrobenzo[d][1,3]oxazine-2-thiones as progesterone receptor modulators leading to the potent and selective nonsteroidal progesterone receptor agonist tanaproget.

Tanaproget represents a potential first-in-class nonsteroidal PR agonist for contraception with improved safety and side effect profiles versus currently available steroidal oral contraceptives. Additional SAR, biological activity, and structural information from a tanaproget/hPR-LBD (hPR-LBD = human progesterone receptor ligand binding domain) cocrystal structure will also be presented.

Alkaline Phosphatase↗
PubMed1998

Development of orally active oxytocin antagonists: studies on 1-(1-[4-[1-(2-methyl-1-oxidopyridin-3-ylmethyl)piperidin-4-yloxy]-2- methoxybenzoyl]piperidin-4-yl)-1,4-dihydrobenz[d][1,3]oxazin-2-one (L-372,662) and related pyridines.

The previously reported oxytocin antagonist L-371,257 (2) has been modified at its acetylpiperidine terminus to incorporate various pyridine N-oxide groups. This modification has led to the identification of compounds with improved pharmacokinetics and excellent oral bioavailability. The pyridine N-oxide series is exemplified by L-372,662 (30), which possessed good potency in vitro (Ki = 4.1 nM, cloned human oxytocin receptor) and in vivo (intravenous AD50 = 0.71 mg/kg in the rat), excellent oral bioavailability (90% in the rat, 96% in the dog), good aqueous solubility (>8.5 mg/mL at pH 5.2) which should facilitate formulation for iv administration, and excellent selectivity against the human arginine vasopressin receptors. Incorporation of a 5-fluoro substituent on the central benzoyl ring of this class of oxytocin antagonists enhanced in vitro and in vivo potency but was detrimental to the pharmacokinetic profiles of these compounds. Although lipophilic substitution around the pyridine ring of compound 30 gave higher affinity in vitro, such substituents were a metabolic liability and caused shortfalls in vivo. Two approaches to prevent this metabolism, addition of a cyclic constraint and incorporation of trifluoromethyl groups, were examined. The former approach was ineffective because of metabolic hydroxylation on the constrained ring system, whereas the latter showed improvement in plasma pharmacokinetics in some cases.

Administration, Oral↗
PubMed1997

An in vitro assessment of the antineoplastic potential of 2H-1,3-oxazine-2,6(3H)-dione (3-oxauracil), a novel pyrimidine.

The pyrimidine (uracil) analogue 3-oxauracil (OU) previously had been shown to completely inhibit the growth of E. coli B and decrease by 96% the replication of herpes simplex virus type 2 when present in the culture fluid at a concentration of 10(2) microM. Limited in vivo studies in mice demonstrated antiviral effects without significant toxicity when given i.p. daily for two weeks at a concentration of 3.23 mg/kg. However, the antineoplastic properties of OU were unknown. We assessed the ability of OU to inhibit the proliferation of various human tumor cell lines (3 pancreatic, 1 colon, 1 neuroendocrine, and 1 lung) in an in vitro radiometric (Bactec) system. In the pancreatic lines (RWP-2, MiaPaCa-2, and PANC-1), the colon line (HT-29), the neuroendocrine line (COLO 320DM), and the lung cancer cell line (SK-MES-1), OU at a concentration of 10(3) microM, produced a dramatic decrease in percent cell survival. When compared with cytotoxic drugs of choice for these tumor cells (gemcitabine, 5-fluorouracil, and adriamycin, respectively) a significantly higher concentration of OU was required usually to achieve comparable results with two exceptions. These were the HT-29 and the COLO 320DM cell lines. These results indicate OU has significant (p < 0.05) cytotoxic activity against pancreatic, colon, neuroendocrine, and nonsmall cell lung cancer lines, when compared to untreated control cultures. Additional in vivo testing of this potential antineoplastic agent is warranted.

Antimetabolites, Antineoplastic↗