Oxepines, dihydro

Dibenz[6,/]oxepin, 10,11-dihydro-applications, 7, 590 Dibenz[c,e]oxepin, dihydro-conformational interchange, 7, 549 Dibenz[6,/]oxepinylpiperazine, 10,11-dihydro-properties, 7, 590 Dibenz[6,g]oxocin synthesis, 7, 669... 

Oxepin, 2-acetoxy-2,3,4,5-tetrahydro-thermal reactions, 7, 559 Oxepin, 3-chloro-synthesis, 3, 725 Oxepin, 2,3-dihydro-cycloaddition reactions, 7, 563 nucleophilic reactions, 7, 562 reduction, 7, 563 Oxepin, 2,5-dihydro-synthesis, 7, 578, 580 Oxepin, 4,5-dihydro-formation, 7, 579 reduction, 7, 563 synthesis, 7, 579 Oxepin, 2,7-dimethyl-NMR, 7, 552... 

H-Pyran, 2-alkoxy-4-methyl-2,3-dihydro-conformation, 3, 630 4H-Pyran, 2-amino-IR spectra, 3, 593 synthesis, 3, 758 4H-Pyran, 4-benzylidene-synthesis, 3, 762 4H-Pyran, 2,3-dihydro-halogenation, 3, 723 hydroboration, 3, 723 oxepines from, 3, 725 oxidation, 3, 724 reactions, with acids, 3, 723 with carbenes, 3, 725 4H-Pyran, 5,6-dihydro-synthesis, 2, 91 4H-Pyran, 2,6-diphenyl-hydrogenation, 3, 777 4H-Pyran, 6-ethyl-3-vinyl-2,3-dihydro-reactions, with acids, 3, 723 4H-Pyran, 2-methoxy-synthesis, 3, 762 4H-Pyran, 2,4,4,6-tetramethyl-IR spectra, 3, 593 4H-Pyran, 2,4,6-triphenyl-IR spectra, 3, 593... 

The dehydrohalogenation reaction has been extended to benzannulated oxepins. Elimination of hydrogen bromide from 3-bromo-4-phenyl-2,3-dihydro-l-benzoxepin with 1,5-diazabicyclo-[4.3.0]non-5-ene gives 4-phenyl-1-benzoxepins 15a15 and 15b16 in low yield. 

In a similar reaction, 2,3,6-trimethoxydibenz[6,/]oxepin gives 10,11-dihydro-2,3,6-trimeth-oxydibenz[/>,/]oxepin-cw-10,l 1-diol upon treatment with osmium(VIII) oxide in the presence of A-methylmorpholine A -oxide.262 When treated with acid the diol undergoes a pinacol rearrangement to the corresponding xanthene-9-carbaldehyde. 

When dimethyl 3-benzoxepin-2,4-dicarboxylate is reacted under controlled conditions (15 min) with hydrogen it is possible to isolate dimethyl l,2-dihydro-3-benzoxepin-2,4-dicarboxylate.17 Hydrogenation of 2-nitrodibenz[, /]oxepin-10-carboxylic acid in the presence of palladium on potassium carbonate results in the reduction of the nonaromatic C C double bond and the nitro group to give 2-amino-10,l l-dihydrodibenz[i,/]oxepin-10-carboxylic acid.107... 

Bromomethyl-3,4-dibromo-3,4-dihydrocoumarin 1 (Fig. 11.4) and its chloro-methylated analogue 2b rapidly and progressively inactivate a-chymotrypsin and also the activities of a series of trypsin-like proteases. A benzyl substituent characteristic of good substrates of a-chymotrypsin was introduced at the 3-position to make inhibition more selective. This substituted dihydrocoumarin 3 irreversibly inhibited a-chymotrypsin and other proteases. These functionalized six-membered aromatic lactones, and their five- and seven-membered counterparts, 3//-benzofuran-2-ones 2a26 and 4,5-dihydro-3//-benzo[b]oxepin-2-ones 2c,27 were the first efficient suicide inhibitors of serine proteases. Their postulated mechanism of action is shown in Scheme 11.2. 

Oxatricyclo[3.2.0.02,4]hept-6-enes or -heptanes are converted to oxepins or 4,5-dihydro derivatives on heating.66-68 This is of interest for certain substitution patterns, for example fluorinated oxepins 4.68... 

Another common method for the preparation of benzene and naphthalene epoxides is by introduction of double bonds into the dihydro precursors. This is generally achieved by bromination-dehydrobromination. Thus unsubstituted benzene oxide-oxepin (86 96) can be obtained by dehydrohalogenation of the dibromocyclohexane epoxide 99, using a basic amine or sodium methoxide in ether.53... 

Oxidative coupling of substituted bibenzyl ethers with phenyliodine(m) bis(trifluoroacetate) affords 6,7-dihydro-577-dibenzfo oxepines (Equation 17) <1998JOC7698>. 

The acyl migration of the glucuronide metabolite of the model drug 6,11-dihydro- 11 -oxodibenz (b,e) oxepin-2-acetic acid has also been investigated in urine and pH 7.4 buffer using directly coupled 600 and 750 MHz stop-flow HPLC H NMR spectroscopy [53,54],... 

Chemical Name 10,11-Dihydro-a,8-dimethyl-ll-oxodibenz[b,f]oxepin-2-acetic acid... 

A mixture of dl-2-[4-(2 -carboxymethyl-4 -methylphenoxy)phenyl]propionic acid (15.3 g) and polyphosphoric acid (92 g) was heated with stirring at 110-120°C for 2 hours. To the reaction mixture was added water and the resulting mixture was extracted with chloroform. The organic layer was washed with water, dried over anhydrous sodium sulfate and concentrated. The residue was chromatographed on silica gel (75 g) using chloroform as an eluent to give a crude product, which was recrystallized from toluene to give the dl-2-(8-methyl-10,ll-dihydro-ll-oxodibenz[b,f]oxepin-2-yl)propionic acid (9.4 g, 65.3%), m.p. 128-129°C. 

A number of vinyl cyclopropane diols upon treatment with Dess-Martin reagent and pyridine underwent oxidation accompanied by rearrangement to give formyl dihydro-oxepins [30] ... 

Konformativ bestandig werden jedoch auch die Dihydro-oxepine 24 durch Einfiihrung zweier Substituenten in der ortho-Stellung zur Bi-phenyl-Bindung. Die optisch aktiv vorliegenden Dimethoxy- und Di-chlor-Derivate 24 (R = OCH3 bzw. Cl, X=0) racemisieren erst beim Erhit-zen in Losung (Ea = 29,9 kcal/Mol, log ko = 13,4 sec-1 bzw. Ea = 34,8 kcal/Mol, log k0= 13,3 sec-1) 13< . 

Die absolute Konfiguration mehrerer optisch aktiv vorliegender Dihydro-oxepine und -thiepine konnte mit Hilfe von ORD- und CD-Kurven bestimmt werden 38>13°). 

---