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At least 19 recordsLinked to original sources
PubMed2006

A novel oxazine ring closure reaction affording (Z)-((E)-2-styrylbenzo[b]furo[3,2-d][1,3]oxazin-4-ylideno)acetaldehydes and their anti-osteoclastic bone resorption activity.

A novel oxazine ring formation method was established using the reaction of 2-acetyl-(E)-3-styrylcarbonylaminobenzo[b]furans (4) with Vilsmeier-Haack-Arnold reagent to afford (E and Z)-((E)-2-styrylbenzo[b]furo[3,2-d][1,3]oxazin-4-ylideno)acetaldehydes (5). (Z)-4-(8-Bromo-(E)-2-styrylbenzo[b]furo[3,2-d][1,3]oxazin-4-ylideno)but-(E)-2-enoic acid ethyl ester (6b), derived from (Z)-5a, showed significantly potent anti-osteoclastic bone resorption activity comparable to 17beta-estradiol (E2).

Benzofurans↗
PubMed1991

Synthetic approaches to the guanosine and xanthosine analogues 5-amino-3-beta-D-ribofuranosylpyrazolo[3,4-e][1,3]oxazin-7-one and 3-beta-D-ribofuranosylpyrazolo[3,4-e][1,3]oxazine-5,7-dione and studies of their antitumor potential.

5-Amino-3-beta-D-ribofuranosylpyrazolo[3,4-e][1,3]oxazin-7-o ne has been synthesized via cyclization of the appropriately protected pyrazofurin derivatives and subsequent transformations of the heterocyclic moiety. This guanosine analogue was marginally cytotoxic to L1210 cells in vitro. The xanthosine analogue 3-beta-D-ribofuranosylpyrazolo[3,4-e][1,3]oxazine-5,7-dione was also synthesized, and was found to be highly cytotoxic. It appeared to act as a prodrug of pyrazofurin.

Animals↗
PubMed2004

Stereoelectronic effects in ring-chain tautomerism of 1,3-diarylnaphth[1,2-e][1,3]oxazines and 3-alkyl-1-arylnaphth[1,2-e][1,3]oxazines.

The disubstitution effects of X and Y in 1-(Y-phenyl)-3-(X-phenyl)-2,3-dihydro-1H-naphth[1,2-e][1,3]oxazines on the ring-chain tautomerism, the delocalization of the nitrogen lone pair (anomeric effect), and the (13)C NMR chemical shifts were analyzed by using multiple linear regression analysis. Study of the three-component equilibrium B<==>A<==>C revealed that the chain<==>trans (A<==>B) equilibrium constants are significantly influenced by the inductive effect (sigma(F)) of substituent Y on the 1-phenyl ring. In contrast, no significant substituent dependence on Y was observed for the chain<==>cis (A<==>C) equilibrium. There was an analogous dependence for the epimerization (C<==>B) constants of 1-(Y-phenyl)-3-alkyl-2,3-dihydro-1H-naphth[1,2-e][1,3]oxazines. With these model compounds, significant overlapping energies of the nitrogen lone pair was observed by NBO analysis in the trans forms B (to sigma*(C1-C1'), sigma*(C1-C10b), and sigma*(C3-O4)) and in the cis forms C (to sigma*(C1-H), sigma*(C1-C10b), and sigma*(C3-O4)). The effects of disubstitution revealed some characteristic differences between the cis and trans isomers. However, the results do not suggest that the anomeric effect predominates in the preponderance of the trans over the cis isomer. When the (13)C chemical shift changes induced by substituents X and Y (SCS) were subjected to multiple linear regression analysis, negative rho(F)(Y) and rho(F)(X) values were observed at C-1 and C-3 for both the cis and trans isomers. In contrast, the positive rho(R)(Y) values at C-1 and the negative rho(R)(X) values at C-3 observed indicated the contribution of resonance structures f (rho(R) > 0) and g (rho(R) < 0), respectively. The classical double bond-no-bond resonance structures proved useful in explaining the substituent sensitivities of the donation energies and the behavior of the SCS values.

Journal Article↗
PubMed2003

2-silyloxy-1,2-oxazines, a new type of acetals of conjugated nitroso alkenes.

3-alkyl-substituted 1,2-oxazine N-oxides 2 can be selectively transformed into 2-silyloxy-1,2-oxazines 1 upon treatment with silylating reagents. In the solid state derivatives 1 adopt a chair conformation with the pyramidal nitrogen atom, whereas in solution they exist as an equilibrating mixture of two conformers (DeltaG++ 55-60 kJ/mol). A preliminary study of the reactivity of nitrosals 1 has shown that they react with O- and N-stabilized carbocations to yield 1,2-oxazine N-oxides with a functionalized alkyl substituent at the 3-position. Moreover, compounds 1 can rearrange into silyloxy-1,2-oxazines 5 and react with morpholine to produce 3-morpholinoalkyl-1,2-oxazines 7 existing in a tautameric equilibrium with open-chain oximes 6.

Journal Article↗
PubMed1992

Qualitative analysis of the stability of the oxazine ring of various benzoxazine and pyridooxazine derivatives with proton nuclear magnetic resonance spectroscopy.

A series of 3,4-dihydro-1,3-benzoxazine and 3,4-dihydro-1,3-pyridooxazine derivatives was synthesized, and the hydrolysis of the derivatives was studied with proton nuclear magnetic resonance spectroscopy. The oxazine derivatives underwent various degrees of hydrolysis when H2O was added to dimethyl sulfoxide solutions of the compounds. The rates and extents of decomposition of the oxazine ring systems depended on the electronic effects of substituents within the molecules. Examination of the proton nuclear magnetic resonance spectra that were generated during decomposition of the oxazines and trends in stability of the oxazine derivatives suggest the formation of an intermediate in the hydrolysis mechanism.

Drug Stability↗
PubMed1975

2-Aryloxymethyl-2,3,5,6-tetrahydro-1,4-oxazines, a new class of antidepressants.

Some 2-aryloxymethyl-2,3,5,6-tetrahydro-1,4-oxazines have been shown to possess marked antidepressant activity. The 1,4-oxazines were synthesized by lithium aluminum hydride reduction of the readily available 6-aryloxymethyl-2,3,5,6-tetrahydro-1,4-oxazin-3-ones. High antidepressant activity was associated with ortho substitution of the 2-phenoxymethyl group and with 1,4-oxazines devoid of 4-substituents.

Animals↗
PubMed2005

Oxazine 170 induces DNA:RNA:DNA triplex formation.

The oxazine dye (Oxazine 170) was found to induce formation of a hybrid triplex structure, poly rA:(poly dT)(2), under solution conditions in which the triplex would not otherwise form. Formation of the hybrid triplex is driven by the structural selective binding of oxazine 170 to poly rA:(poly dT)(2). Oxazine 170 serves as a lead compound for the design of new compounds that can modulate triplex formation.

Dialysis↗
PubMed2005

Synthesis of tricyclic 1,3-oxazin-4-ones and kinetic analysis of cholesterol esterase and acetylcholinesterase inhibition.

A series of thieno[1,3]oxazin-4-ones and thieno[1,3]thiazin-4-ones were synthesized and investigated as inhibitors of the alpha/beta hydrolases cholesterol esterase (CEase) and acetylcholinesterase (AChE). The introduction of a cycloaliphatic five- or six-membered ring fused at the thiophene was favorable for CEase inhibition. Such compounds were analyzed as true alternate substrate inhibitors. 6,7-Dihydro-2-(dimethylamino)-4H,5H-cyclopenta[4,5]thieno[2,3-d][1,3]oxazin-4-one (33) exhibited a K(i) value of 630 nM and excelled in its low susceptibility to CEase-catalyzed degradation. Compound 33 and its analogues did not inhibit AChE. The introduction of a tetrahydropyrido ring with bulky hydrophobic substituents at the basic nitrogen provided inhibitors of AChE which were completely inactive toward CEase. 7-Benzyl-5,6,7,8-tetrahydro-2-(N-3,4-dimethoxybenzyl-N-methylamino)-4H-pyrido[4',3':4,5]thieno[2,3-d][1,3]oxazin-4-one (21) had the IC(50) value of 330 nM for AChE inhibition. A residual enzymatic activity at an infinite inhibitor concentration and thus a catalytically active ternary enzyme-substrate-inhibitor complex was concluded. To specify kinetic parameters of inhibition, a new method was derived to characterize selected thieno[1,3]oxazin-4-ones as hyperbolic mixed-type inhibitors of AChE.

Acetylcholinesterase↗
PubMed1986

[Compounds with anti-gastric secretion and antiulcer activity. V. Derivatives of 3,3,4a,6,7,11b-hexahydro-2H,5H-benzo [1,4]cyclohep[1,2-b][1,4]-oxazine and related products].

A series of hexahydrobenzo[3,4]cyclohept[1,2-b][1,4]oxazines, with different substituents at the benzene and oxazine rings and nitrogen atom, was synthetized. The diastereomers and enantiomers of the unsubstituted compound and the related derivatives hexahydrobenzo[5,6] and exahydrobenzo[6,7]cyclohept[1,2-b][1,4]oxazine, hexahydro[1]benzoxepine and hexahydro[1]benzothiepin[5,4-b][1,4]oxazine, octahydrobenzo[3,4]cyclohept[1,2-b][1,4]diazine were also prepared. Some of these compounds inhibited at low doses gastric secretion in pylorus-ligated rats and antagonized ulcers in pylorus-ligated rats plus acetylsalicylic acid and in cold+restraint-stressed rats. When the most active compounds were tested on cats with Heidenhain pouch, they induced unwanted side effects that ruled out further development of these chemical series.

Animals↗
PubMed2004

Spirobipyridopyrans, spirobinaphthopyrans, indolinospiropyridopyrans, indolinospironaphthopyrans and indolinospironaphtho-1,4-oxazines: synthesis, study of X-ray crystal structure, antitumoral and antiviral evaluation.

The novel racemic indolinospirobenzopyrans (5-7), indolinospironaphthopyrans (11-14) and indolinospironaphtho-1,4-oxazine (17) were synthesized by an aldol type of condensation of 1',3',3'-trimethyl-2 '-methyleneindoline and its 5-substituted derivatives with an appropriately substituted hydroxybenzaldehyde, hydroxynaphthaldehyde or nitrosonaphthol. An unequivocal proof of the stereostructures of 9 and 17 was obtained by the single-crystal X-ray diffraction method. A substituted indoline ring and the benzopyran ring in 9 and the naphtho-1,4-oxazine moiety in 17 are interconnected via the common chiral atom and positioned almost perpendicularly to each other. The five-membered 2,3-dihydropyrrolo moiety of the indoline ring adopts an envelope conformation in both structures. Of all the compounds of this series, spirobipyridopyran (1) inhibited specifically the growth of human melanoma (HBL) (IC(50): 0.9 microM) cells but not the growth of normal fibroblasts (WI38). Indolinospirobenzopyrans (8-10) showed significant cytostatic activities against all tumor cell lines. However, these compounds also exhibited a cytotoxic effect on normal human fibroblasts. The indolinospirobenzopyrans 4, 6-8, 10 and the indolinospironaphtho-1,4-oxazine 16 showed, albeit modest, selectivity as antiviral agents against varicella-zoster virus (VZV) and/or cytomegalovirus (CMV) (EC(50) within the concentration range of 1.0-12.6 microM).

Antineoplastic Agents↗
PubMed2004

Synthesis, structure, and catalytic properties of V(IV), Mn(III), Mo(VI), and U(VI) complexes containing bidentate (N, O) oxazine and oxazoline ligands.

Synthesis of seven complexes containing oxazoline ([(L(1))(2)V=O] (4), [(L(1))(2)MoO(2)] (5), [(L(1))(2)UO(2)] (6); HL(1) (1) [HL(1) = 2-(4',4'-dimethyl-3'-4'-dihydroxazol-2'-yl)phenol]), chiral oxazoline ([(L(2))(2)UO(2)] (7); HL(2) (2) [HL(2) = (4'R)-2-(4'-ethyl-3'4'-dihyroxazol-2'-yl)phenol]), and oxazine ([(L(3))(2)V=O] (8), [(L(3))(2)Mn(CH(3)COO(-))] (9), [(L(3))(2)Co] (10); HL(3) (3) [HL(3) = 2-(5,6-dihydro-4H-1,3-oxazolinyl)phenol]) and their characterization by various techniques such as UV-vis, IR, and EPR spectroscopy, mass spectrometry, cyclic voltammetry, and elemental analysis are reported. The novel oxazine (3) and complexes 4, 5, 8 and 9 were also characterized by X-ray crystallography. Oxazine 3 crystallizes in the monoclinic system with the P2(1)/n space group, complexes 4 and 9 crystallize in the monoclinic system with the P2(1)/c space group, and complexes 5 and 8 crystallize in the orthorhombic system with the C222(1) space group and the P2(1)2(1)2(1) chiral space group, respectively. The representative synthetic procedure involves the reaction of metal acetate or acetylacetonate derivatives with corresponding ligand in ethanol. Addition of Mn(OAc)(2).4H(2)O to an ethanol solution of 3 gave the unexpected complex Mn(L(3))(2).(CH(3)COO(-)) (9) where the acetate group is coordinated with the metal center in a bidentate fashion. The catalytic activity of complexes 4-9 for oxidation of styrene with tert-butyl hydroperoxide was tested. In all cases, benzaldehyde formed exclusively as the oxidation product.

Catalysis↗
PubMed1976

Synthesis and pharmacological evaluation of some 3-substituted octahydropyrido(2,1-c)(1,4)oxazines.

3-Phenyloctahydropyrido[2,1-c][1,4]oxazine hydrochloride and the 10R and 10S diastereomers have been synthesized from (+/-)-, (+)-, and (-)-2-piperidinemethanol. Treatment of 2-piperidinemethanol with alpha-bromoacetophenone gave 3-hydroxy-3-phenyloctahydropyrido[2,1-c][1,4]oxazine which was readily converted to the 3-phenyl derivative by catalytic hydrogenolysis. These compounds were shown to possess a depressant action on the CNS which was quantitated in terms of reduction of locomotor activity in mice. Qualitative differences were noted in the central effects of the 3-phenyl compound and its hemiketal derivative. Further, qualitative differences in the effects of the diastereomers of the 3-phenyl compound on locomotor activity of mice were also noted. The results of this study suggest that the octahydropyrido[2,1-c]1,4]oxazine system may provide a useful molecular framework for the construction of agents exhibiting pharmacologically useful actions in the CNS.

Animals↗
PubMed1976

Synthesis and biological studies of 3-(beta-D-ribofuranosyl)-2,3,-dihydro-6H-1,3-oxazine-2,6-dione, a new pyrimidine nucleoside analog related to uridine.

Reaction of the trimethylsilyl derivative of 2,3-dihydro-6H-1,3-oxazine-2,6-dione (2, "uracil anhydride") with protected 1-O-acetylribofuranoses in the presence of stannic chloride gave the corresponding block nucleosides. 3-(2,3-5-Tri-O-2',2',2'-trichloroethoxycarbonyl-beta-d-ribofuranosyl)-2,3-dihydro-6H-1,3-oxazine-2,6-dione (4c) thus prepared from the protected sugar 3c, 1-O-acetyl-2,3,5-tri-O-(2,2,2-trichloroethoxycarbonyl)ribofuranose, gave, on removal of the protecting groups with zinc dust,3-(beta-d-ribofuranosyl)-2,3-dihydro-6H-1,3-oxazine-2,6-dione (1). The structure of 1 was confirmed by uv, ir, NMR, and CD spectral data and was shown to be an N nucleoside. Uracil anhydride, 2, and, to a lesser extent, its ribonucleoside 1 exert a moderate growth inhibition of mouse leukemia L5178Y, HeLa, and Novikoff hepatoma cells i- culture. Both compounds produce weak inhibition of vaccinia viral replication in HeLa cells.

Animals↗