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Benzoxazine derivatives

Isoxazoles substituted in the 3-position, but unsubstituted in the 5-position, react under more vigorous conditions to give acids and nitriles (Scheme 24). Anthranils unsubstituted in the 3-position are similarly converted into anthranilic acids by bases (Scheme 25) (67AHC(8)277). Attempted acylation of anthranils gives benzoxazine derivatives via a similar ring opening (Scheme 26) (67AHC(8)277). [Pg.71]

Scheme 6.264 Multistep synthesis of substituted benzoxazine derivatives. Scheme 6.264 Multistep synthesis of substituted benzoxazine derivatives.
Treatment of the (—)-menthone-derived 2/7-1,3-benzoxazin-4(3//)-one 202 with triflic anhydride gave the triflate 203 in quantitative yield. Palladium-catalyzed cross-coupling of 203 with 2-pyridylzinc halide resulted in formation of an approximately 3 1 mixture of the 4-(2-pyridyl)-2//-l,3-benzoxazine 204 and a 4-imino-l,3-benzodioxane derivative 205 (Scheme 36). Compound 205 was formed by the isomerization of 203, which occurred with complete retention of stereochemistry. The 4-(2-pyridyl)-l,3-benzoxazine derivative 204 was applied in enantioselective allylic alkylations of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate as a chiral ligand inducing a 62% ee in the product <2005JOM(690)2027>. [Pg.401]

In the reactions of the perhydro-l,3-benzoxazine derivatives 236 with benzeneselenyl chloride in dichloromethane-methanol, methoxyselenylation of the double hond in the C-2 side chain occurred in a highly regio- and diastereo-selective way (Scheme 43). Reductive deselenylation of 237 with triphenyltrn hydride in the presence of a catalytic amount of azobisisobutytonitrile (AIBN) resulted in formation of the methoxy derivatives 238 <2006JOC2424>. [Pg.406]

Through the in situ deprotection of A-acyl-2-(trimethylsilyl)ethynylanilines 465 followed by palladium-catalyzed cyclization-methoxycarbonylation, stereoisomeric 4-methoxycarbonylmethylene-3,l-benzoxazine derivatives 466 and 467 were obtained (Equation 51). The (Z)-isomers 466 were consistently found to be the main product, with the exception of the -(methoxycarbonyl)phenyl-substituted compounds (R = H, = C6H4C02Me(/>)), for which a... [Pg.433]

The condensation of 2-(5-bromo-4-chloro-2-hydroxybenzoyl)pyridine 506 in a sealed tube with ammonia and acetone proved a convenient route to 2//-l,3-benzoxazine derivative 225 via the imine intermediate 507 <1996CPB734>. The yield was improved considerably and a closed vessel was not required for the reaction when the ammonia was prepared in situ from NH4I and piperidine, and 2,2-dimethoxypropane was used instead of acetone (Scheme 95). The improved method was extended to the preparation of other 2,2-disubstituted-2//-l,3-benzoxazine derivatives <2001T7501>. [Pg.438]

Regioselective aminomethylation and subsequent cyclization of methyl 2,4-dihydroxybenzoate 517 was accomplished through a Mannich reaction with formaldehyde and primary amines in methanol to yield 3-substituted-3,4-dihydro-2/7-l,3-benzoxazine derivatives 518 (Equation 60). Simultaneous mixing of the reactants resulted in poor yields, but good yields were achieved by the pretreatment of paraformaldehye with a primary amine to form a Schiff base, followed by the addition of compound 517 <2001TL7273>. [Pg.440]

Reactions of the salts 79-81 with chloroacetonitrile, methyl chloroacetate, chloroacetone, or substituted phenacyl bromide yield different products the thiazoles 90 are formed in excellent yield from the reaction with 79 (Equation 1) and when salts 80 and 81 are treated with phenacyl bromide, thiazolopyridine 91 and benzoxazine derivative 92 are formed, respectively <2004H(63)2319>. [Pg.577]

Aminobenzyl alcohols (298) give 4,4-dialkyl-4//-3,1 -benzoxazine derivatives (299) on treatment with acetic anhydride (1883CB2576). [Pg.636]

Arylazo-3-benzofuryl-4(//)-l,4-benzothiazine 320a (92AP205) and 1,4-benzoxazine derivative 320b (92AP205) have been prepared by the reaction of the hydrazonoyl bromide 34 with o-aminothiophenol and o-aminophenol, respectively. [Pg.328]

In addition to high-performance liquid chromatography (HPLC), the chiral resolution using CMPAs was also carried out by supercritical fluid chromatography (SFC) [91] and capillary electrochromatography (CEC) [92-98]. Salvador et al. [91] used dimethylated /1-cyclodextrin as the mobile phase additive on porous graphite carbon as the solid phase for the chiral resolution of tofizopam, warfarin, a benzoxazine derivative, lorazepam, flurbiprofen, temazepam, chlorthalidone, and methyl phehydantoin by SFC. The authors also studied the effect of the concentration of dimethylated /1-cyclodextrin, the concentration of the mobile phase, the nature of polar modifiers, outlet pressure, and the column temperature on the chiral resolution. [Pg.366]

Hofman, J. and Hofmanova, O. 1971. 1,4-Benzoxazine derivative in plants absence of 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one from uninjured Zea mays plants. Phytochemistry 10, 1441-1444... [Pg.264]

Oxidation of the o/T/zo-substituted acetanilides 324 with DMP leads to the isolable o-iminobenzoquinones 325 (Scheme 94) (02JA2221). The imino-quinones undergo inverse electron demand Diels-Alder reactions with the vinyl ether and vinyl sulfide shown in Scheme 94, thus providing access to the benzoxazine derivatives 326 and 327. [Pg.283]

In the reaction of aromatic or heterocyclic carboxylic acids with adjacent reactive groups with two equivalents of carbodiimides also heterocycles are readily obtained. For example, salicylic acid 608 reacts with aliphatic carbodiimides to give benzoxazine derivatives 609, together with the corresponding urea. ... [Pg.106]

By electrolysis of 2-bromoamides in DMF the aminal esters (492 Scheme 89) are accessible. In the reaction of benzoylphenyl ketene with the isoquinolinedione (493) the heterocyclic aminal ester (494) is formed. Another heterocyclic aminal ester (496) was obtained from a hydrazinoyl chloride and a benzoxazine derivative (495). ... [Pg.575]

As with calixphenols I, the different reactivity of O-acylated and unsubstituted resorcinol rings in the C2v-symmetric derivatives 76 may be used for selective electrophilic substitutions. Distally disubstituted derivatives were obtained, for instance, by bromination or aminomethylation with secondary amines . The Mannich reaction of tetrasulphonates 76c and tetrabenzoates 76d with primary amines led to C2-symmetric bis-benzoxazine derivatives in a regioselective manner . Various trani-cavity bridged compounds were obtained with primary diamines of different length , including enantiomerically pure, distally bridged resorcarenes when a chiral secondary diamine was used . Removal of the Boc-protection in products obtained by aminomethylation... [Pg.1420]

The main substrates that have been investigated as partners in cyclization reactions are phenols. As with reactions involving secondary amines, phenols react with aldehydes and primary amines principally ortho to the hydroxy group. A reaction of the first-formed secondary amine with a second molecule of aldehyde can therefore lead to the formation of a benzoxazine derivative. A wide range of phenols, includ-... [Pg.968]

Kadatz first described the anti-inflammatory and other pharmacological properties of a benzoxazine derivative, 2-(/3-chloroethyl)-2,3-dihydro-4-oxobenz-l,3-oxazine (Ap67, chlorthenoxazin, XLII, R = H). The compound possesses anti-inflammatory, analgesic and antipyretic properties... [Pg.96]

Perhydro derivatives (497), (498), and (514) were synthesized from [4 + 2] atom fragments by reacting the morpholine derivative (513) with bifunctional electrophiles (Scheme 41), for example, ethyl chloroacetate and diethyl oxalate <64AP(297)632>. The [l,4]oxazino[4,3,2-de]-l,4-benzoxazine derivative (515) was prepared in the reaction between chloropentafluorobenzene and diethanolamine <88MI 825-03). [Pg.703]

Blattes E, Fleury M-B et al (2004) Simultaneously electrogenerated cycloaddition partners for regiospecific inverse-electron-demand Diels-Alder reactions a route for polyfunctiona-lized 1,4-benzoxazine derivatives. J Org Chem 69 882-890... [Pg.391]

P. Velez-Herrera, H. Ishida, Synthesis and characterization of highly fluorinated diamines and benzoxazines derived therefrom, J. Ruo-rine Chem. 130 (6) (2009) 573-580. [Pg.175]

Benzoxazine derivatives have been shown to possess pharmacological properties and 1,3-oxazine derivatives are widely known for their potential as antibiotics, antitumor compounds, analgesics, and anticonvulsants. In 2012, Bao and co-workers developed a novel and efficient synthesis of benzoxazine and 1,3-oxazine derivatives via a ligand-free copper(i)-catalyzed one-pot cascade addition-cyclization reaction (Scheme 3.72). A variety of carbo-diimides coupled with o-halophenylmethanols and/or substituted (Z)-3-iodoprop-2-en-l-ols to give the corresponding products in moderate to excellent yields under mild conditions. [Pg.249]


See other pages where Benzoxazine derivatives is mentioned: [Pg.266]    [Pg.366]    [Pg.405]    [Pg.405]    [Pg.419]    [Pg.434]    [Pg.448]    [Pg.261]    [Pg.299]    [Pg.110]    [Pg.291]    [Pg.108]    [Pg.323]    [Pg.327]    [Pg.27]    [Pg.120]    [Pg.282]    [Pg.354]    [Pg.299]    [Pg.241]    [Pg.352]    [Pg.222]    [Pg.665]   
See also in sourсe #XX -- [ Pg.271 ]




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Benzoxazine

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