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4.5- Dihydro-3,1 -benzoxazepines

In 1984, we demonstrated that A-alkoxy-A-acyl nitrenium ions 15 could be generated by the reaction of A-alkoxy-A-chloroamides 14 with Lewis acids such as Ag + and Zn2+ and used these to form heterocycles by intramolecular aromatic substitution reactions (Scheme 2).90 In this manner, several novel A-acyl-3,4-dihydro-2,l-benzoxazines 16a and A-acyl-4,5-dihydro-( I //,3//)-2,1-benzoxazepines 16b were made. Subsequent work91,92 and that of Kikugawa93 96 produced numerous syntheses involving alkoxynitrenium ions including formation of natural products.97 99... [Pg.38]

The AgBp4 method was extended to cyclizations onto the alkoxyl side chain. Novel heterocycles A-acyl-3,4-dihydro-lP -2,l-benzoxazines (25) and A-acyl-4,5-dihydro-l//,3//-2,1-benzoxazepines (26) were synthesized by the treatment of open-chain A-chloro-A-(2-phenylethyloxy)- and A-chloro-A-(3-phenylpropyloxy)amides (24, n = 2, 3) with silver tetrafluoroborate in benzene (Scheme 2). Optimal yields of 25 were ultimately obtained with AgBp4 in ether or TPIP. ... [Pg.855]

Monocyclic 1,3-oxazepines (325) with aryl substituents at the 2-, 4- and 7-positions can be prepared in moderate yield (20-40%) by the reaction of aliphatic diazo compounds with 1,3-oxazinium perchlorates (324) (74S187). Tetra- and penta-phenyl-l,3-oxazepines (328 R = H or Ph) have been obtained via the reaction of azide with pyrylium salts (326) (78H(l 1)331). This principle had earlier been applied to the preparation of 1,3-benzoxazepines (74CR(C)(278)1389> and more recently to 3,1-benzoxazepines (81JHC847). The preparation of 2-phenyl-1,3-oxazepine.(331) by the UV irradiation of (329) is mechanistically interesting in that it apparently involves an intermediate (330) of the same type as (327) (73TL1835), but the method has only been used in this one case. One of the few examples of a dihydro-1,3-oxazepine (333) has been prepared by the thermolysis of the aziridine (332) (68JOC4547). [Pg.627]

Aryl-2,3-dihydro-l,4-benzoxazepines (366) have been prepared by a Bischler-Napieralsky-type cyclization (76BSB787). [Pg.630]

There has been little systematic study of the chemistry of 1,4-oxazepines. Vigorous acid hydrolysis cleaves the amide linkage in (369 R1=Ph, R2 = H) and recyclization gives 2-o-hydroxyphenyl-5-phenyloxazoline and l,2,3,4-tetrahydro-l,8-dihydroxy-3-phenyl-isoquinoline. The l,4-benzoxazepin-5-one (353) can be alkylated at N but on treatment with triethyloxonium fluoroborate it is converted to 5-ethoxy-3-phenyl-l,4-benzoxazepine — one of the very few examples of a fully unsaturated 1,4-oxazepine ring. This product is isomerized to l-ethoxy-4-hydroxy-3-phenylisoquinoline when boiled in methanol. The 4,l-benzoxazepine-2,5-diones (348) are converted to quinazolines by reaction with ammonia. The dihydro-l,4-oxazepin-5-one (343) can be acetylated at nitrogen and bromi-nated at the 6-position. [Pg.631]

The copper-catalyzed insertion of isocyanides (316) into the O—H bond of alcohols gives a high yielding route to 4,5-dihydro-3,l-benzoxazepines (317) (78TL2087). [Pg.637]

Chemical Name 2H-Benzimidazol-2-one, l,3-dihydro-l-[l-[(4-methyl-4H,6H-pyrrolo[l,2-a][4,l]benzoxazepin-4-yl)methyl]-4-piperidinyl]-, maleate (1 1)... [Pg.3501]

To a solution of 7.5 g thereof, in 300 ml of tetrahydrofuran is added 5 g of l,l -carbonyldiimidazole and the resultant mixture stirred at room temperature for 1 hour. To this mixture is added 5 g of l,3-dihydro-l-(4-piperidyl)-2H-benzimidazol-2-one, and the reaction is heated at reflux temperature for 48 hours. After cooling to room temperature, the reaction mixture is poured into 150 ml of ice-water and extracted into 150 ml of methylene chloride. The organic extracts are washed successively with 150 ml of sodium carbonate solution, 150 ml of water and 150 ml of dilute hydrochloric acid, then dried over magnesium sulfate, filtered, and the solvent is evaporated under reduced pressure to yield l,3-dihydro-l- l-[(4-methyl-4H,6H-pyrrolo[l,2-a][4,l]benzoxazepin-4-yl)carbonyl]-4-piperidinyl -2H-benzimidazol-2-one, m.p. 208°-210°C. [Pg.3502]

The acid-catalysed reaction of acetonitrile with either the benzo-l,2,3-dioxathepane 2-oxide 308 [01JGU150] or the dihydro-2,3,4-benzodioxasilepine 308a [01JGU295] affords the benzoxazepine derivative 309, although in very low yield from the latter alkaline hydrolysis then yields the amino alcohol 310. [Pg.423]

Benzo c,d indol 4-Amino-2-oxo-l, 2-dihydro- XI/1, 151 3,4-Benzo-2-oxa-7-aza-bicyclo 3.2.0 hepta-3,6-dien 1-Cyan-8-methyl- IV/5b, 1307 1,3-Benzoxazepin 2-Cyan-4-meihyl-lV/5b, 1307/E9d, 307 (1 -CN — 3-R — isoquinolin-2-oxid hv)... [Pg.842]

Scheme 2 8-Methoxy-4,5-dihydro-l,4-benzoxazepin-2(3/t)-one Derivative Intermediate in the Activation of N -Protected A -(2-Hydroxy-4-methoxybenzyl) Amino Acids ... Scheme 2 8-Methoxy-4,5-dihydro-l,4-benzoxazepin-2(3/t)-one Derivative Intermediate in the Activation of N -Protected A -(2-Hydroxy-4-methoxybenzyl) Amino Acids ...
A further development of this safety-catch principle led to A -[2-hydroxybenzyl-4-methoxy-5-(methylsulfinyl)] (SiMB) derivatives (Scheme 4) where the acylation potency of the intermediate 8-methoxy-4,5-dihydro-l,4-benzoxazepin-2(3//)-one derivatives (Scheme 2) is significantly enhanced and similarly the rate of intramolecular O N acyl migration. The related Fmoc-protected amino acid derivatives are readily prepared and cleavage is achieved by reductive acidolysis (SiCl4/TFA/anisole/ethandithiol 5 90 2.5 2.5, 2h at room temperature). [Pg.266]


See other pages where 4.5- Dihydro-3,1 -benzoxazepines is mentioned: [Pg.566]    [Pg.566]    [Pg.566]    [Pg.566]    [Pg.566]    [Pg.566]    [Pg.315]    [Pg.316]    [Pg.149]    [Pg.372]    [Pg.1529]    [Pg.1543]    [Pg.447]    [Pg.626]    [Pg.626]    [Pg.566]    [Pg.566]    [Pg.3502]    [Pg.447]    [Pg.448]    [Pg.448]    [Pg.448]    [Pg.843]    [Pg.210]    [Pg.871]    [Pg.885]    [Pg.1116]    [Pg.264]    [Pg.266]    [Pg.99]    [Pg.566]    [Pg.566]    [Pg.626]    [Pg.630]   
See also in sourсe #XX -- [ Pg.637 ]




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