Potassium phenyl derivatives

Alkyl-3-ethoxy-4-[(mesyloxy)methyl]-l,4-dihydroisoquinolines 27 on treatment with potassium /Vrt-butoxide in dimethyl sulfoxide undergo ring expansion to 1/7-2-benzazepines.24 0 (For related ring expansions of acridines, see Section 3.2.1.4.1.5.) The 4-methyl and 4-methyl-l-phenyl derivatives 27a and 27b, respectively, yield mixtures of the 3-ethoxy-5-methyl- 28 and 3-ethoxy-4-methyl- 29 l//-2-benzazcpines cyclopropaquinolines are thought to be involved as intermediates (see Section 3.2.1.4.1.6.). In contrast, the 4-[l-(mesyloxy)ethyl] derivatives 27e and 27d yield only the 4,5-dimethyl-li/-2-benzazepines 29c and 29d. 

The selective basic degradation of 1,2-dicarbaclovodode-carborane(12) and its C-methyl and C-phenyl derivatives has been recently reported.3 The ethanolic potassium hydroxide degradation of C, C"-dimethyl-l, 2-dicarbaclovododecaborane (12) and the isolation of the trimethylammonium salt of the resulting B9C2Hio(CH3)2 anion are described here as an illustration of this general reaction. The properties of the trimethylam-... 

The reaction of potassium dienoxy borates with A-fluorobis(phenylsulfonyl)amine (la) gives y-fluoro enones in good yield. The potassium dienoxy borates are prepared by treating potassium enolates derived from unsaturated ketones with 2-phenyl-1,3,2-benzodioxaborole. This methodology offers a convenient alternative to the traditional fluorination of dienol acetates, ethers, or enamines.145 An example is given by the formation of 13.145... 

Although this cyclization is similar to those employed in the syntheses of oxygen and sulfur analogs of heterocycles 80 by reaction of 81 with potassium telluride does not allow the preparation of 2-phenyl derivatives of 80. 

Nitrations of phenyl derivatives of small ring heterocycles have been little studied. The nitration of 3-(4-nitrophenyI)-l-phenyl-2,2-dichloroaziri-dine (90) using potassium nitrate in sulfuric and acetic acids yields 1,3-bis(4-nitrophenyl)-2,2-dichloroaziridine and 3-(4-nitrophenyl)-l-(2-nitro-phenyl)-2,2-dichloroaziridine in 65 35 ratio. Under the same conditions the diphenyl derivative undergoes cleavage of the aziridine ring to give a mixture of nitrated anilides. 

Acylisoxazoles yield furazans on heating with alkaline hydroxylamine, presumably by oximation and subsequent rearrangement. Likewise 3-benzohydroximino-4-benzoyl-5-phenylisoxazole when treated with 20% potassium hydroxide is reported to give 3-dibenzoylmethyl-4-phenylfurazan, which was subsequently converted to the 3-phenacyl-4-phenyl derivative on further reaction with alkali or acid. 

The amino group can be protected by forming its sulfonyl [such as arylsulfonyl or 2-(trimethylsilyl) ethyl sulfonyl], sulfenyl and silyl derivatives. The 2- or 4-nitrophenylsul-fonamide derivatives of amino acids are useful substrates for mono-N-alkylation using only cesium carbonate (CS2CO3) as the base. The sulfonamide group can be removed in 1.89 by potassium phenyl thiolate (PhSH and K2CO3) in acetonitrile to give the N-alkylated a-amino esters 1.90 and the reaction occurs without racemization. 

Quach and Batey299 reported the coupling of primary amines with phenylboronic acids catalyzed by Cu(OAc)2 (10 mol%) without base or ligand but in the presence of 4 A molecular sieves and air in CH2C12 solvent (equation 73). Reactions of potassium phenyl-trifluoroborate also occurred, but in lower yields than reactions of boronic acids. They showed that these reactions occur with a variety of functional groups on the amine, including alkenes, esters, ketones and ketals. a-Amino acid derivatives underwent reaction without detectable epimerization. Anilines were poorer cross-coupling partners under these conditions than were primary and secondary cyclic aliphatic amines. 

Attempts to aromatize 4,5,6,7-tetrahydroanthranils have met with only moderate success.2 The 3-cyclohexyl derivative is unaffected by sulfur at 200°C and by chloranil, whereas the 3-methyl and 3-phenyl derivatives with 5% palladium charcoal in boiling decalin yield only o-aminoacylketones. However, dibromination (probably at positions 4 and 7) of 185 (R = Ph) with JV-bromosuccinimide followed by dehydrobromination in methanolic potassium hydroxide furnishes 3-phenylanthranil. 

Vinyl carbanions derived from acrylic esters and their jS-phenyl derivatives react with several carbon electrophiles to give a-substituted and a,/8-disub-stituted derivatives. While /8>alkyl substituted acrylates have been shown to dimerize in the presence of potassium catalyst at 110 C. Three simple unsaturated esters undergo palladium(0)-catalysed codimerization with methylenecyc-lopropane to furnish methylenecyclopentanecarboxylic esters in reasonable yield. An efficient procedure for the oxidation of isatins to anthranilic acid esters has appeared. Methyl 2,4,6-tri-isopropylbenzoate forms a dipole-stabilized carbanion on reaction with Bu Li, which then reacts with carbon electrophiles [e.g. E = Bui, (CH3)2C0, or CH3CHO] to give a range of ester derivatives in good yield (Scheme 52). ... 

The nitration of l,2,5-selenadiazolo[3,4-/] quinoline 77 with benzoyl nitrate affords the 8-nitro derivative 78, whereas methylation with methyl iodide or methyl sulfate afforded the corresponding 6-pyridinium methiodide 79 or methosulfate 80, respectively (Scheme 29). The pyridinium salt 80 was submitted to oxidation with potassium hexacyanoferrate and provided 7-oxo-6,7-dihydro derivative 81 or, by reaction of pyridinium salt 79 with phenylmagnesium bromide, the 7-phenyl-6,7-dihydro derivative 82. Nucleophilic substitution of the methiodide 79 with potassium cyanide resulted in the formation of 9-cyano-6,9-dihydroderivative 83, which can be oxidized by iodine to 9-cyano-l,2,5-selenadiazolo [3,4-/]quinoline methiodide 84. All the reactions proceeded in moderate yields (81IJC648). 

Cleavage of the acetate unit(s) in 5-acetoxy- and 3,5-diacetoxy-4-phenyl-l-benzothiepins 11 with potassium carbonate in methanol at room temperature does not stop at the diketone stage, but further undergoes ring contraction to the thiophene derivative 12 in 55-80% yield.90... 

The diastereoselectivity and the stereochemical outcome of the addition of 2,3,4,6-tetrahydro-3, 4-dimethyl-2-phenyl-1,4-oxazepine-5,7-dione, derived from ephedrine and methyl hydrogen malonate, to 1 -nitrocyclohexene was found to be dependent on the nature of the base and the solvent. The highest diastereoselectivity was obtained when potassium /tr/-butoxide in the presence of dicyclohcxyl-18-crown-6 was employed. In the absence of crown ether the diastereoselection was poor and the sense of the stereochemical outcome was reversed26. 

The cyclopropane cyclizations by elimination of triflinic acid (CF3S02H) are readily effected by basic treatment of triflones (trifluoromethyl alkyl sulfones) with activated /-protons (equations 46 and 47)39. The cyclopropane diesters 45 are formed on treatment of 44 with potassium hydride in DMSO or sodium methoxide in methanol (equation 48). In contrast, the monoester 46 failed to give the desired cyclopropane40. Addition of carbanions derived from /f, y-unsaturated phenyl sulfones to a, /i-unsaturated carboxylic esters and subsequent elimination of benzenesulfinate ion give cyclopropanes possessing the unsaturated side chain and the ester function in trans positions (equation 49)41. 

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