Selective defluorination approach to N-Cbz-3,3-difluoro-2-difluoromethylenepyrrolidine and its application to 3,3-difluoroproline dipeptide synthesis

Mg-promoted defluorination of N-(p-methoxyphenyl)bis(trifluoromethyl)imine 1 gave perfluoroenamine 2, which was readily transformed to N-Cbz-2-trifluoromethyl-3,3-difluoropyrrolidine 10. Chemoselective defluorination from the trifluoromethyl group of 10 by LHMDS-promoted dehydrofluorination in THF provided 3,3-difluoro-2-difluoromethylenepyrrolidine 11. The product 11 was converted to 3,3-difluoroproline dipeptides 16 upon treatment with aminoesters.     

Synthesis, characterizations and luminescent properties of terbium complexes with methoxy derivatives of 2'-hydroxy-2-phenylacetophenone

The complexes Tb(L(1))(3).2H(2)O (I) {where L(1)=2'-hydroxy-4'-methoxy-2-phenylacetophenone}, Tb(L(2))(3).2H(2)O (II) {where L(2)=2'-hydroxy-4'-methoxy-2-(p-methoxyphenyl)acetophenone}, Tb(L(3))(3).2H(2)O (III) {where L(3)=2'-hydroxy-4',6'-dimethoxy-2-phenylacetophenone} and Tb(L(4))(3).2H(2)O (III) {where L(4)=2'-hydroxy-4',6'-dimethoxy-2-(p-methoxyphenyl)acetophenone} were synthesized and characterized by IR spectroscopy, TGA/DTA and elemental analysis. The qualitative analysis of the complexes to detect the presence of terbium has been performed by energy dispersive analysis (EDAX). The synthesized complexes on exposure to UV light (354 nm) emit green luminescent with main peak at 546 nm. The complexes emitting bright green colour might be promisingly applicable for optical devices and solid-state lamps for general illumination purposes.     

CuCl-K(2)CO(3)-catalyzed highly selective borylcupration of internal alkynes - ligand effect

An efficient and practical copper-catalyzed highly regio- and stereoselective borylcupration of internal alkynes with bis(pinacolato)diboron using a catalytic amount of K(2)CO(3) as base producing Z-alkenylboron compounds has been demonstrated by applying the ligand effect: commercially available electron-rich tris(p-methoxyphenyl) phosphine ensures a smooth and efficient reaction. Functionalized alkynes, such as propargylic alcohols and derivatives as well as N-propargyl tosylamide, may also be used with excellent selectivity.     

First generation of pentazole (HN5, pentazolic acid), the final azole,and a zinc pentazolate salt in solution: A new N-dearylation of 1-(p-methoxyphenyl) pyrazoles,a 2-(p-methoxyphenyl) tetrazole and application of the methodology to 1-(p-methoxyphenyl) pentazole

Ceric ammonium nitrate (CAN) in methanol-water gave a new N-dearylation of a series of substituted 1-(p-methoxyphenyl) pyrazoles and a 2-(p-methoxyphenyl)tetrazole producing p-benzoquinone and the parent azole in a mole for mole ratio. Application of this reaction to 1-(p-methoxyphenyl) pentazole at -40 degrees C produced p-benzoquinone. 15N NMR spectra suggest that pentazole, HN5, was also produced and held in solution as N5- with Zn2+ ion. The 15N signal from N5- was -10.0 +/- 2.0 ppm in agreement with calculated values.     

Rearrangement of a 2-methylenecyclobutanone derivative triggered by photoinduced electron transfer: an unprecedented oxa analogue of the tetramethyleneethane radical cation

On irradiation of p-chloranil (CA), 2,2-bis(p-methoxyphenyl)-3,3-dimethyl-4-methylenecyclobutanone (1) gives 2,2-bis(p-methoxyphenyl)-4-isopropylidenecyclobutanone (2), whereas 2 affords a CA adduct (4), suggesting that a novel rearrangement of 1 to give 2 occurs irreversibly via intermediate 3*+, a radical cation variant of an unprecedented oxa analogue of tetramethyleneethane.     

CATALYTIC SYNTHESIS OF α-CYANO-α,β-UNSATURATED SULPHONES IN THE PRESENCE OF ORGANOTELLURIUM OXIDE

Using bis(p-methoxyphenyl)telluroxide(BMPTO)as the catalyst,phenylsulphonyl acetonitrile condensed easily with aromatic aldehydes atroom temperature to give -cyano- ,β-unsaturated sulphones in high yields.     

Reactions of Bis(p-methoxyphenyl)trisulfane and Its Oxides with Dimethyldioxirane and (Trifluoromethyl)methyldioxirane

The reactions of dimethyldioxirane and (trifluoromethyl)methyldioxirane with bis(p-methoxyphenyl)trisulfane, its 1-oxide, its 2-oxide, and its 1,1-dioxide derivatives have been investigated. The reactions were followed by careful monitoring of the methoxy region of the (1)H NMR spectra and where possible by doping with authentic samples of the products. The decomposition of labile intermediates and products was investigated. A new mechanism for the rearrangement of a trisulfane 1,3-dioxide to a trisulfane 1,1-dioxide is proposed.     

One-electron oxidation of anispinacolone with diaroyl peroxides: Mechanistic changeover of the peroxide function from radical to molecular oxidation

Oxidative cleavage of anispinacolone (An₃C·CO·An, An=p-methoxyphenyl) with diaroyl peroxides proceeds by electron-transfer mechanism, which starts with rate-determining decomposition of the peroxide, unimolecular for dibenzoyl and bimolecular for bis(3,5-dinitrobenzoyl) peroxide.     

Nickel-catalyzed four-component connection of oraganoaluminium (organozinc), isoprene, aldehydes and amines: stereo- and regioselective synthesis of trisubstituted (E)-homoallylamines

Ni(acac)2 catalyzes the four-component connection reaction of trimethylaluminium (or diphenylzinc), isoprene, aromatic aldehydes and p-anisidine in this order and provides (E)-1-aryl-1-(p-methoxyphenyl)amino-3-methyl-3-hexenes (or (E)-1-aryl-1-(p-methoxyphenyl)amino-3-methyl-5-phenyl-3-pentenes) selectively in good yield.     

芳环取代的俘精酸酐的合成及光致变色反应研究

本文报道四个芳环取代的俘精酸酐:2-亚异丙基-3-[1-(4-甲氧苯基)-亚乙基]-丁二酸酐(BF1); 2-亚异丁基-3-[1-(4-甲氧苯基)-亚乙基]-丁二酸酐(BF2);2-亚异丙基-3-[1-(α-萘基)-亚乙基]-丁二酸酐(NF1); 2-亚异丙基-3-[1-(β-萘基)-亚乙基]-丁二酸酐(NF2)的合成及其光致变色性质。测定了它们在不同溶剂中光致变色前后的吸收光谱。利用纳秒级激光闪光光解技术研究了它们的光致变色过程, 并讨论了其光致变色机理。结果表明, 这类芳环取代的俘精酸酐的光致环合反应是经过激发单重态进行的快速过程。     

1-Ethyl- and 1,2-dimethyl-3-(p-methoxyphenyl)benzo[f]quinolines and their transformations

Condensation of p-methoxybenzylidene-2-naphthylamine with methyl ethyl ketone leads to a mixture of 1-ethyl- and 1,2-dimethyl-3-(p-methoxyphenyl)benzo[f]quinolines, for which protic and quaternary salts were obtained. Cyanine dyes were synthesized from 1,2-dimethyl-3-(p-methoxyphenyl)benzo[f]quinoline methiodide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1223–1226, September, 1976.     

Synthesis of Glucoside Bonded Metal Porphyrins

Enzyme catalyzed reaction often has high selectivity and efficiency under mild conditions. However, disadvantage of enzyme catalysts is the difficulty of recovery. Metalloporphyrin plays an important role in biological system such as redox reaction, electron transfer,oxygen transportation and charge separation etc.1,2 Metalloporphyrins as superoxide dismutase (SOD) mimics have showed the ability of catalyzing the redox reaction of some harmful radicals , such as O2·―, ·OH. Grove and co-…     

Color tunable phosphorescent light-emitting diodes based on iridium complexes with substituted 2-phenylbenzothiozoles as the cyclometalated ligands

Several iridium complexes {iridium(III)bis[2-(3-methoxyphenyl)-1,3-benzothiozolato-N,C^2′] acetylacetonate (MeO-BT)₂Ir(acac), iridium(III)bis[2-(2,4-difluorophenyl)-1,3-benzothiozolato-N,C^2′] acetylacetonate (2F-BT)₂Ir(acac), and iridium(III)bis[2-(2,4-difluorophenyl)-6-fluoro-1,3-benzothiozolato-N,C^2′] acetylacetonate (3F-BT)₂Ir(acac)} having different substituents on 2-phenylbenzothiazole have been synthesized. The phosphorescent light emitting diodes (PHOLEDs) using these iridium complexes as dopant emitters were fabricated. The experimental results revealed that the emissive colors of PHOLEDs could be finely tuned by suitable modification of the substituents on the 2-phenylbenzothiazole ligands. Furthermore, these iridium complexes show better emissive properties than the known iridium(III)bis(2-phenylbenzothiozolato-N,C^2′) acetylacetonate (BT)₂Ir(acac).     

Enantioselective synthesis of (2R,4'R,8'R)-alpha-tocopherol (vitamin E) based on enzymatic function

Syntheses of (S)-chroman-2-carboxaldehyde congener 1 and (S)-chiral isoprene unit 3 were achieved based on the enzymatic acetylation of (+/-)-chroman-2-methanol 6 and (+/-)-(2,3)-anti-2-methyl-3-(p-methoxyphenyl)-1,3-propane diol 12, respectively. Synthesis of the side-chain part corresponding to (3R,7R)-3,7,11-trimethyldodecan-1-ol 27 was achieved by the coupling reaction of (S)-3 and (R)-3,7-dimethyloctyl iodide 4. The Wittig reaction of (3R,7R)-phosphonium salt 2 derived from (3R,7R)-27 and (S)-1 gave the olefin 28 which was subjected to catalytic hydrogenation to afford (2R,4'R,8'R)-alpha-tocopherol.     

Synthesis of a new conformationally defined serotonin homologue by intramolecular [4+2] cycloaddition

Treatment of 1-[(p-methoxyphenyl)sulfonyl]-2-methyl-3-[N-allyl-N-methyl-3-(2,6-dichlorobenzoyl)propylamino]indole 3 with triethylamine in chlorobenzene at 135°C results in the formation of 1,2,3,4,4a,5,6,11c-octahydro-7-[(p-methoxypyhenyl)-sulfonyl]-3-methyl-7H-pyrido[3,4-c]carbazole 1b in 58% yield. The reaction is selective in giving predominantly the trans isomer.     

Asymmetric synthesis of (4R,5R)-cytoxazone and (4R,5S)-epi-cytoxazone

(4R,5R)-Cytoxazone has been prepared in four steps and in 61% overall yield and >98% ee. Conjugate addition of lithium (R)-N-benzyl-N-[small alpha]-methylbenzylamide to tert-butyl (E)-3-(p-methoxyphenyl)prop-2-enoate and subsequent in situ diastereoselective enolate oxidation with (+)-(camphorsulfonyl)oxaziridine gave tert-butyl (2R,3R,[small alpha]R)-2-hydroxy-3-(p-methoxyphenyl)-3-(N-benzyl-N-[small alpha]-methylbenzylamino)propanoate in >98% de. Subsequent N-benzyl deprotection to the primary [small beta]-amino ester via hydrogenolysis, oxazolidinone formation with C(2)-retention by treatment with diphosgene and chemoselective ester reduction furnishes (4R,5R)-cytoxazone. The synthesis of the C(5)-epimer, (4R,5S)-epi-cytoxazone in 44% overall yield, has also been completed via a protocol involving N-Boc protection of the primary [small beta]-amino ester, utilization of the N-Boc group to facilitate simultaneous C(2)-inversion and oxazolidinone formation, and subsequent reduction.     

Bromination of 4-(p-methoxyphenyl)-2,3-dihydro-1h-1, 5-benzodiazepin-2-one

Mono- and dibromo derivatives were obtained in the bromination of 4-(p-methoxyphenyl)-2,3-dihydro-1H-1, 5-benzodiazepin-2-one in media with different acidities with N-bromosuccinimide in carbon tetrachloride. The UV, PMR, and mass spectra of the compounds obtained are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 842–846, June, 1979.     

Five-membered-ring-substituted 1-methyl-1H-indeno[1,2-b]pyridines

1-Methyl-1H-indeno[1,2-b]pyridine and 1-methyl-1H-5-(, -dicarbomethoxyvinyl)-(formyl, acetyl)indeno[3,2-b]pyridines were obtained by treatment of N-methyl-4-azafluorenium iodide, as well as mixtures of it with acetylenedicarboxylic ester, dimethylformamide (DMF), and phosphorus oxychloride or acetic anhydride, with bases. 4-Azafluoronenone was used to synthesize 9-(p-methoxyphenyl)-4-azafluoren-9-ol, which was reduced to 9-(p-methoxyphenyl)-4-azafluorene, and 1-methyl-1H-5-(p-methoxyphenyl)indeno[3,2-b]pyridine was obtained from the methiodide of the latter.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1382–1386, October, 1981.     

Hantzsch synthesis of 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(o-methoxyphenyl)-1,4-dihydropyridine; a novel cyclisation leading to an unusual formation of 1-amino-2-methoxy-carbonyl-3,5-bis(o-methoxyphenyl)-4-oxa-cyclohexan-1-ene

Hantzsch condensation of two equivalents of methyl-3-aminocrotonate with (m- and p)-methoxybenzaldehyde afforded the expected products 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(m-methoxyphenyl)-1,4-dihydropyridine and 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(p-methoxyphenyl)-1,4-dihydropyridine, whereas o-methoxy-benzaldehyde produced mainly 1-amino-2-methoxycarbonyl-3,5-bis(o-methoxy-phenyl)-4-oxa-cyclohexan-1-ene. The structure of the product, not previously reported in the literature, was determined by 1D and 2D NMR spectra and its MS fragmentation. This is the first example of cyclisation leading to a substituted pyran rather than 1,4-DHP under typical Hantzsch reaction conditions. A plausible mechanism for its formation is postulated.     

Condensation of ethyl esters of 6-phenyl-and 6-(p-methoxyphenyl)-2,4-dioxocyclo-hexane-1-carboxylic acids with N-benzylidene-2-naphthylamines

A number of ethyl esters of 2,5-diaryl-4-hydroxy-1,2,5,6-tetrahydrobenzo[a]phenanthridine-3-carboxylic acid were obtained by condensation of ethyl esters of 6-phenyl- and 6-(p-methoxyphenyl)-2, 4-dioxocyclohexane-1-carboxylic acids with N-benzylidene-2-naphthyla-mines, and their spectral characteristics were studied. It was established that the luminescence properties of these compounds and the character of their reaction with the solvent are determined by the proton-acceptor properties of the carbonyl and hydroxy groups.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 976–979, July, 1980.