Benzo 2-ethoxy

Benzo[b]furan, 2,3-dihydro-2-phenyl-synthesis, 4, 697 Benzo[b]furan, 2,3-dihydroxy-tautomerism, 4, 37 Benzo[6]furan, 4,6-dimethoxy-acylation, 4, 606 Benzo[6]furan, 2,3-dimethyl-acetylation, 4, 606 bromination, 4, 605 photooxygenation, 4, 642 Benzo[b]furan, 5,6-dimethyl-2,3-diphenyl-applications, 4, 709 Benzo[b]furan, 1,3-diphenyl-vertical ionization potential, 4, 587 Benzo[b]furan, 2-ethoxy-5-hydroxy-synthesis, 4, 127... 

Aza-3,4-benzo-5,6-dipropylpentatriafu]valene hydriodide (373) was obtained in 20% yield by the action of l,2-di-n-propyl-3-ethoxy-cyclopropenium fluoroborate on indole magnesium iodide in a methylene chloride-ether mixture. 

Starting from l.l-dichloro-7b-ethoxy-2-methyl-1,1 a,2,7-tetrahydrobenzo[/)]cyclopropa[prepared from the corresponding benzothiopyran by addition of dichlorocarbene, the three 1-benzothiepins 6a-c are formed upon treatment with strong bases, i.e. sodium methoxide or ethoxide in dimethyl sulfoxide.73 The optimal yield of each 1-benzo-thiepin compound depends on the molar equivalents of base, as follows from different ring-opening mechanisms. 

Ethoxy-3//-azepin-3-ones, e.g. 2, are produced rapidly (2-20 min), as yellow gums, by the oxidation of 7-ethoxy-6-hydroxy-4/T-azepines,e.g. 1, with2,3-dichloro-5,6-dicyano-l,4-benzo-quinone (DDQ) in benzene.48,51... 

CN [6-Hydroxy-2-(4-hydroxyphenyl)benzo[fc]thien-3-yl][4-[2-(l-piperidinyl)ethoxy]phenyl]methanone hydrochloride... 

The first attempted synthesis of a benzo[ ]thiepin derivative was the solvolysis of 7,7-dichloro-3,4-benzo-2-thiabicyclo[4.1,0]heptene (19)20). Unfortunately, the reaction of 19 in hot quinoline led to 2-chloronaphthalene which suggested the reaction mechanism as shown below. In the case of the reaction of l,l-dichloro-7b-ethoxy-... 

The synthetic procedures outlined in Section 3 provide ready access to a wide variety of benzo[7>]thiepins in which the substituents are methyl, formyl and ethoxy-carbonyl. The thermal stability of the thiepins was conveniently evaluated from the half-lives of their sulfur extrusion reactions by means of H-NMR spectroscopy. The half-lives of a series of substituted benzo[b]thiepins and naphtho[2,3-f>]thiepins thus obtained are summarized in Table 1. 

Benzannulated NHPs are straightforwardly accessible from AUV-disubsti luted o-phenylenediamines either via base-induced condensation with substituted dichlorophosphines [25] or PC13 [26], or via transamination with tris(dialkylamino) phosphines [13, 14, 27], respectively. An analogous NH-substituted derivative was obtained in low yield via transamination of o-phcnylcncdiaminc with ethoxy-bis(diethylamino)phosphine [28], and condensation of o-phenylenediamine with excess tris(diethylamino)phosphine furnished a l,3-bis(phosphino)-substituted heterocycle [29], Intermediates with one or two NH functions were detectable by spectroscopy but could not be isolated in pure form under these conditions. However, 2-chloro-benzo-l,3,2-diazaphospholene and the corresponding 1-phenyl derivative were prepared in acceptable yield via condensation of PC13 with o-phenylenediamine under microwave irradiation [30], or with A-phenyl-o-phenylenediamine under reflux [27], respectively, in the absence of additional base. The formation of tetrameric benzo-NHPs during transamination of A-alkyl-o-phenylenediamines with P(NMe2)3 has already been mentioned (cf. the section entitled 1,3,2-Diazaphospholes and 1,3,2-Diazaphospholides ). 

On the other hand, the metabolism of benzo[a]pyrene, ethoxy-coumarin and ethoxyresorufin, which are preferentially oxidized by rodent cytochrome P -450, was greatly induced by the polyhalogenated biphenyls and 3-naphthoflavone. Despite large changes in... 

Methyl-2-phenyl-oxazol-4-yl)ethoxy]benzo[2]thiophen-7-yl]methyl]-thiazolidine-2,4-dione. 

Ethoxy-2/7-l-benzothiopyran with dichlorocarbene yields the dichlorocyclopropane (67),279 280 which in the presence of hot quinoline279 produces the thiochromone (68), or with methoxide280 forms the ring-expanded benzo[6]thiepin (69) and 2//-l-benzothiopyran (70), as in Scheme 13. Reaction of dichlorocarbene with the simple 2//-l-benzo-thiopyran (4) produces281 the dichloromethyl derivatives (71) and (72) of Eq. (33). 

The normal reactions of benzo[6]thiophene 1,1-dioxides have been reviewed (70AHC(11)177). Electrophilic substitution (nitration, bromination) takes place at position 6. 3-Halo derivatives undergo normal nucleophilic displacement reactions, but 2-bromobenzo[6]thiophene dioxide gives the 3-ethoxy derivative in ethanolic NaOH. The reaction of 3-methoxy derivatives with secondary amines can give rise either to enamines... 

Friedel-Crafts acylation of benzo[6]thiophene usually gives a mixture of 2- and 3-substituted isomers, in which the 3-isomer predominates (Section 3.14.2.4). However, various electron-releasing groups elsewhere on the ring system may favor 2-acylation. Certainly 3-alkyl- or 3-methoxy-benzo[h]thiophenes are acylated exclusively in the 2-position, and 5,6-dimethoxy-, 5,6-methylenedioxy- and 6-ethoxy-benzo[f>]thiophenes are acylated predominantly in the 2-position (70AHC(11)177). 

Treatment of the disulfide (90) with iodine in dioxane under various conditions gives low yields of 5,6-dimethoxy-2,3-dihydrobenzo[6]-thiophene.346 At high temperatures in ethylene glycol a mixture of this compound and the dehydrogenated product, 5,6-dim ethoxy-benzo[6]thiophene, is obtained. These observations demonstrate the importance of the double bond in the side chain of the mercapto-acrylic acids (88) in promoting their cyclization. 

Tetrahydrobenzo[6]thiophene103 and several benzo[6]thio-phenes containing electron-donating substituents, e.g., 5,6-dimeth-oxy,180 5,6-methylenedioxy,180 6-ethoxy,424 3-methoxy,183 and 3-methyl,487 are smoothly brominated in the 2-position by iV-bromo-succinimide in carbon tetrachloride or chloroform in the absence of peroxides. Similar treatment of 2-methoxybenzo[6]thiophene gives the 3-bromo derivative.183... 

Thioindoxyl and its 6-ethoxy derivative undergo the Reformatsky reaction with ethyl bromoacetate to give the corresponding 3-benzo-[6]thienylacetic acid, on alkaline hydrolysis of the reaction mixture.569... 

Diethyl - 0 - (6 - m ethoxy - 3 - benzo[ ]thienyl)phosphorothioate and a number of related compounds may be prepared similarly.607 These compounds exhibit pesticidal activity. 

Hydroxybenzo[6]thiophene has been isolated from coal tar.42 It may be prepared from 6-aminobenzo[fr]thiophene by standard procedures.241 6-Methoxybenzo[h]thiophene may be prepared by decarboxylation of the corresponding 2-carboxylic acid,341 and 6-ethoxybenzo[6]thiophene is obtained by reduction of 6-(ethoxy)-thioindoxyl (Section VI, 1,2). 6-Methoxy-5-methylbenzo[6]thiophene is obtained by cyclization of (3-methoxy-4-methylphenylthio)-acetaldehyde dimethyl acetal (Section IV,B).617 The product previously described542 as 6-hydroxy-3-phenylbenzo[6]thiophene has now been shown to be the 2-phenyl isomer.307 6-Methoxy-818 and 6-methoxy-5-methyl-benzo[6]thiophene617 are demethylated by pyridine hydrochloride. 

Benzo[6]thienylacetic acid and its 6-ethoxy derivative are obtained in low yield from the corresponding thioindoxyl by the Reformatsky reaction with ethyl bromoacetate.509 4-Benzo[6]thienylacetic acid is obtained by successive dehydrogenation and hydrolysis of the ester mixture shown in Eq. (10).355,448 7-Benzo[6]thienylacetic acid may be prepared similarly.303... 

In dehydrated benzene, upon irradiation of a 1 x 10 [ 2 M p-ethoxystyr-ylthiophene (235), the isolate product 236 is considered to be 5-(3-ethoxy-1,3-butadienyl)benzo[fc] thiophene. 

The unsubstituted benzo-TA 263 that was generated in situ from 2-ethoxy-2,3-dihydrobenzo-TA 262 reacts with 1,3-dienes to give the Diels-Alder adducts 264 and 265 (73JHC149) possessing a cis-configuration according to the Woodward-Hoffmann rules for [2 + 4]-cycloaddition (Scheme 103). 

Isomerization of benzo[/]-l,5-diazabicyclo[3,2,2]nonene in 8.8 N HBr at 140°C yielded l,2,3,5,6,7-hexahydropyrido[l,2,3-de]quinoxaline (83 KGS677). Photolysis of dimethyl l-(quinolin-8-yl)-l,2,3-triazole-4,5-di-carboxylates in MeCN resulted in stable an/tydro-2,3-dimethoxycarbonyl-3//-pyrido[l,2,3-de]quinoxalin-4-ium hydroxides [87JCS(P1)403]. 6-Hy-droxymethyl-2-methyl-7-methoxy-l,2,3,4-tetrahydro-6//-pyrazino-[1,2-h]isoquinolin-4-one (138) was prepared from 5- [A-methyl-Ar-(ethoxy-... 

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