5.6- Dihydro-4//-indene

For the addition of furan and benzofuran to benzocyclopropene, a diradical mechanism has been proposed for the formation of 4. Similarly, AT,At-dimethyl- or A-methyl-A-phenyl-hydrazones of a,/ -unsaturated aldehydes (acrylaldehyde and 2-methylacrylaldehyde) reacted by radical addition at the C-C double bond with benzocyclopropene at 45 C to yield a dihydro-indene derivative 5. The addition of tetracyanoethene to benzocyclopropene giving dihydro-indene 6a is, however, believed to be preceded by electron transfer from benzocyclopropene to tetracyanoethene.Cyclopropa[b]naphthalene reacted similarly with tetracyanoethene to give the dihydroindene derivative 6b in 44% yield. 

Hydroxy-l-oxo-2-methoxycarbonyl-2,3-dihydro-inden (F 131-132°) und l-Hydroxy-3-mdhoxy-carbonyl-III-(2-benzopyran y (F 110 1110)1 ... 

Dihydro-inden-(2-spiro-l >-l, 3-dihydro-(benzo-[cJ-furan >... 

In a somewhat parallel case,. yy -9-carbethoxy-c/.y-bicyclo[6.1.0]nonatriene epimerized to its anti isomer at 100°C with a half-life of 4 h, but at higher temperatures (130°C) an 86 14 mixture of exo- and Jo-l-carbethoxy-cw-8,9-dihydro-indene, respectively, was formed. Apparently no hydrogen or carbethoxy group migration occurs judging from a deuterium-labeling experiment (Scheme 10.17). 

Acetoxymethyl-ds,trans,cis,trans-cyclonona-l,3,5,7-tetraene, prepared from lithium cyclononatetraenide and bromomethyl acetate at — 30 °C, was converted into 9-methylene-ci5,trans,cis,trans-cyclonona-l,3,5,7-tetraene by KOBuS Both 9-acetoxy-methyl- and 9-methylene-cyclononatetraenides were converted into the dihydro-indenes (222 R = CH2 H, CH2OAC) on warming. ... 

A soln. of the startg. m. and pyrrolidine in anhydrous benzene refluxed 12 hrs. under Ng and a Dean-Stark water separator methyl 5-pyrrolidino-6,7-dihydro-indene-7a(2H)-carboxylate (Y 91%) dissolved in benzene, and refluxed 4 hrs. under Ng with a soln. of Na-acetate in acetic acid-water methyl 6-oxo-5,6-dihydroindane-3a(4H)-carboxylate (Y 81%). Also with a mixture of methyl and ethyl esters as startg. m. s. C. J. V. Scanio and L. P. Hill, Synthesis 1970, 651. 

AlClj Alkylation Process. The first step in the AIQ. process is the chlorination of / -paraffins to form primary monochloroparaffin. Then in the second step, the monochloroparaffin is alkylated with benzene in the presence of AIQ. catalyst (75,76). Considerable amounts of indane (2,3-dihydro-lH-indene [496-11-7]) and tetralin (1,2,3,4-tetrahydronaphthalene [119-64-2]) derivatives are formed as by-products because of the dichlorination of paraffins in the first step (77). Only a few industrial plants built during the early 1960s use this technology to produce LAB from linear paraffins. The C q—CC olefins also can be alkylated with benzene using this catalyst system. 

H-2,3 -Dioxa-2aA -thia-1,4-diazacyclopent-[cd]indene, 6,6-dimethyl-6,7-dihydro-X-ray, 6, 1054 (73XL1565)... 

Thiacyclotrideca-2,4,10,12-tetraene-6,8-diyne 1 -oxide, 5,10-dimethyl- HNMR, 7, 717 (75JA640) 4-Thia-2,6-diazabicyclo[3.2.0]heptane-2-carboxylic acid, 7-OXO-, t-butyl ester X-ray, 7, 349 (B-72M151201) 5H-2aA -Thia-2,3-diazacyclopent[cd]indene, 2,3-dimethyl-6,7-dihydro-X-ray, 6, 1054 (72ACS343)... 

Chemical Name 6-Chloro-5arboxylic acid Common Name —... 

Methyl ( )-2,3-Dihydro-l-oxo-2-(3-oxobutyl)-177-indene-2-carboxylate (2) Typical Procedure245 ... 

K)-6,7-dichIor<)-2,3-dihydro-5-methox -2- 3-oxobutyl)-2-propyl-1 -inden-l-one yield 95% 80% ee... 

The highest enantioselectivities in the base-catalyzed Michael additions have so far been obtained using achiral bases complexed to chiral crown ethers. The addition of methyl 2,3-dihydro-l-oxo-1//-indene-2-carboxylate (1) to 3-buten-2-one using 4 mol% of a [l,T-binaphthalcnc]-2,2 -diol derived optically active crown ether 3 in combination with potassium AY/-butoxide as the base illustrates this successful method 259 260 It is assumed that the actual Michael donor is the potassium enolate complex of 1 and crown ether 3. 

In an oven dried glass flask under an argon atmosphere at — 78 UC, 950 mg (5 mmol) of methyl 2,3-dihydro-1-oxo-l/f-indene-2-carboxylate in 10 mL of toluene are added to 2.2 mg (0.2 mmol) of potassium rert-butoxide in 5 mL of toluene. 356 mg (0.2 mmol) of (5, 6 )-bis[3,3 -dimethyl-l,l -binaphthalene]-2,2 -diol bis(diethy-lencoxy) ether [(5,.5)-3) are added, followed after 10 min by 700 mg (10 mmol) of 3-buten-2-one in 10 mL of toluene and the mixture is stirred for 120 h at — 78 °C after which it is poured into 35 mL of sat. aq NH4C1. The toluene layer combined with a toluene wash solution is dried over MgS04 and evaporated at 40 "C. The crude adduct is purified by chromatography over silica gel (C H2C12) yield 624 mg (48%) 99% ee. 

Dihydro-1-vinylnaphthalene (67) as well as 3,4-dihydro-2-vinylnaphtha-lene (68) are more reactive than the corresponding aromatic dienes. Therefore they may also undergo cycloaddition reactions with low reactive dienophiles, thus showing a wider range of applications in organic synthesis. The cycloadditions of dienes 67 and 68 and of the 6-methoxy-2,4-dihydro-1-vinylnaphthalene 69 have been used extensively in the synthesis of steroids, heterocyclic compounds and polycyclic aromatic compounds. Some of the reactions of dienes 67-69 are summarized in Schemes 2.24, 2.25 and 2.26. In order to synthesize indeno[c]phenanthrenones, the cycloaddition of diene 67 with 3-bromoindan-l-one, which is a precursor of inden-l-one, was studied. Bromoindanone was prepared by treating commercially available indanone with NBS [64]. 

Since dihydroarylethenes are more reactive than the corresponding fully aromatic compounds, their use in the cycloaddition reactions is preferred in order to carry out the reactions under mild conditions with higher yields. Some reactions of 3,4-dihydro-1-vinylnaphthalene (103) [33], 3,4-dihydro-2-vinyl-naphthalene (104) [34], and l,2-dihydro-4-vinylphenanthrene (105) [35] with 4-acetoxy-2-cyclopentenone (98) and 2-inden-l-one (106) are summarized in Schemes 5.11-5.13. 

Benzenediamine (560) and l-diphenylamino-l,2,3,4-tetrahydroindeno[l,2-/tjpyrrole (561) in dichloromethane containing a trace of hydrogen chloride at 20°C during 48 h afforded 3-(l-diphenylhydrazono-2,3-dihydro-l//-inden-2-yl)-2(l//)-quinoxalinone (562) in 53% yield. 

Besides hydroxyethylamine-based inhibitors, 1,2-dihydroxyethylene-based inhibitors were also explored [58]. Only compoimds with the (R,R,R,R)-configuration at the four central carbon atoms demonstrated any inhibitory potency, and a hydroxyindan substituent at the terminal nitrogen atoms improved activity. Hence (2R,3R,4R,5R)-2,5-bis[(prop-2-en-l-yl)oxy]-3,4-dihydroxy-N, N -bis[(lS,2R)-2-hydroxy-2,3-dihydro-lH-inden-l-yl]hexanediamide was selected for an optimization study ( ipUsmepsini = 163 nM, K =... 

CN A-(2,3-dihydro-lff-inden-2-yl)-A ,/V-diethyl-A phenyl-l,3-propanediamine monohydrochloride... 

CN [2S-(2a,5a,6P)]-6-[[3-[(2,3-dihydro-l/7-inden-5-yl)oxy]-l,3-dioxo-2-phenylpropyl]amino]-3,3-dimethyl-7-oxo-4-thia-l-azabicyclo[3.2.0]heptane-2-carboxylic acid... 

CN 6-chloro-5 -cyclohexyl-2,3-dihydro-1 /7-indene-1 -carboxylic acid... 

CN 2,3-dihydro-5,6-dimethoxy-2-[[l-(phenylniethyl)-4-piperidinyl]methyl]-l/7-inden-l-one hydrochloride... 

C7H22N2 140-80-7) see Chloroquinc Mepacnne 7(77)-amino-3-[[(2,5-dihydro-6-hydroxy-2-methyl-5-oxo-l,2,4-triazin-3-yl)thio]mcthyl]-3-cephem-4-carboxylicadd (C12H13N5O5S2 58909-56-1) see Ceftriaxone (15-franx)-l-amino-2,3-dihydro-l//-inden-2-ol (CyH NO 163061-74-3) see Indinavir sulfiite cis-l-amino-2,3-dihydro-l//-inden-2-ol (C9H11NO 7480-35-5) see Indinavir sulfate... 

C6H7NO3S2 138890-97-8) see Brinzolamide dihydro-2-imino-5-methoxy-4,6(1/1,5/I)-pyrimidinedione (C,H7N,0, 89280-05-7) see Sulfametoxydiazine 23-dihydro-2-(l-iminopropyl)-2-[(trimethylsilyl)oxy ]- //-indene... 

C jH2,NOSi) see Indanorex (lS-cii)-2,3-dihydro-l//-indene-l,2-diol (G7H10O2 6752S-22-7) see Indinavir sulfate (laS)-la,6a-dihydro-6//-indenori,2-6]oxirene (CgHjO 67528-26-1) see Indinavir sulfate (2,3-dihydro-l//-inden-4-yl)carbamimidothioic acid methyl ester monohydriodide (C, H 1N2S 40507-77-5) see Indanazoline 23-dibydro-l//-indole-2-carboxylic acid ethyl ester (C iH, N02 50501-07-0) see Perindopril... 

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