Trans-1,2-Dimethyl-1 -phenyl

Dimethyl-phenyl-silyllithium eignet sich zur trans-stereospezifischen Deoxygenierung von Oxiranen zu Alkenen (Carbonyl-Gruppen storen die Reaktion)5 ... 

C12H1404 dimethyl p-phenylenediacetate 36076-25-2 27.00 1.1094 2 24205 C12H160 ( )-trans-2-phenyl-1-cyclohexanol 2362-61-0 20.80 0.9755 2... 

It has been found that at least one phenyl group attached to the cyclopropane ring is a necessary condition for the ring-opening 2,2-diphenyl- and trans-2-phenyl-cyclopropanecarboxylic acid are opened by Na/NHs while 2,2-dimethyl- and cyclopropa-necarboxylic acid are not opened... 

The ms of ais- and trans-1-phenyl-2,5-dimethylphosphorinan-4--one 1-oxide and 1-sulphide and 2,2-dimethyl-1-phenylphos-phorinan-4-one 1-oxide and 1-sulphide have been determined. 

Kapoor P, Lovqvist K, Oskarsson A (1998) Cis/trans influences in platinum(ll) complexes X-ray crystal stmctures of cis-dichlorD(dimethyl sulfide)(dimethyl sulfoxide)platinum(II) and cis-dichloro(dimethyl sulfide)(dimethyl phenyl phosphine)platinum(ll). J Mol Struct 470 39-47... 

Cyclic Disulphides and Cyclic Diselenides.—Formation. No fundamentally new methods of synthesis of this class of compounds have been reported in the past two years. For l,2>dithiolan the oxidation of l,3>dithiols remains a favoured method, the use of iodine in the presence of triethylamine leading smoothly to 1,2-dithiolans without attendant polymerization. cis- and tra/ -l,2-Dithiolan-3,5-dicarboxylic acids were prepared from a diastereo-isomeric mixture of dimethyl 2,4-dibromoglutarates by sequential treatment with potassium thioacetate and potassium hydroxide in the presence of iodine,and jyn-2,3-dithiabicyclo[3,2,l]octan-8-ol was formed from 2,6-dibromocyclohexanone by successive treatment with potassium thiocyanate, lithium aluminium hydride, and iodine. The stereoselective formation of the less thermodynamically stable alcohol in this case was attributed partly to the formation of chelates with sulphur-aluminium bonds. 2,2-Dimethyl-l,3-dibromopropane was converted into 4,4-dimethyl-l,2-diselenolan on treatment with potassium selenocyanate at 175 °C, but at 140 °C the product was 3,3-dimethylselenetan. Reductive debenzylation of 2-alkylamino-l,3-bis(benzylthio)propanes with lithium in liquid ammonia and oxidation of the resultant dithiols with air afforded 4-dialkylamino-l,2-dithiolans, whilst treatment of a-bromomethyl-chalcone with sodium hydrosulphide gave, as minor product, trans-3 phenyl-4-benzoyl-l,2-dithiolan. Among the many products of thermal decomposition of /ra/ -2,4-diphenylthietan was l,4,5,7-tetraphenyl-2,3-dithiabicyclo [2,2,2]octane. ... 

In a manner analogous to classic nitrile iinines, the additions of trifluoro-methylacetonitrile phenylimine occur regiospecifically with activated terminal alkenes but less selectively with alkynes [39], The nitnle imine reacts with both dimethyl fumarate and dimethyl maleate m moderate yields to give exclusively the trans product, presumably via epimenzation of the labile H at position 4 [40] (equation 42) The nitrile imine exhibits exo selectivities in its reactions with norbornene and norbornadiene, which are similar to those seen for the nitrile oxide [37], and even greater reactivity with enolates than that of the nitnle oxide [38, 41], Reactions of trifluoroacetomtrile phenyl imine with isocyanates, isothiocyanates, and carbodiimides are also reported [42]... 

The relative stereostructure of 9-acetyl-7-hydroxy-l,2-dimethyl-7-meth-oxycarbonyl-4-phenyl-6-oxo-l, 4,7,8-tetrahydro-6/7-pyrido[l, 2-u]pyri-midine-3-carboxylate 122 was justified by an X-ray diffraction analysis (97JOC3109). The stereochemistry and solid state structure of racemic trans-6,9-//-l, 6-dimethyl-9 z-ethoxy-9-hydroxy-4-oxo-l,6,7,8,9,9 z-hexahydro-4//-pyrido[l,2- z]pyrimidine-3-carboxylate (123), adopting a cw-fused conformation, were determined by X-ray investigations (97H(45)2175). 

Bei der Hydroaluminierung von Alkinen tritt die Oligomerisierung oft bereits bei nied-rigeren Temperaturen in den Vordergrund. So erhalt man z.B. aus 3,3-Dimethyl-l-phe-nyl-butin (I) und Bis-[2-methyl-propyl]-aluminiumhydrid (1 1) bei 50° 94% d.Th. cis-3,3-Dimethyl-l-phenyl-buten-(l) (II)5 neben 6% d.Th. trans,trans-2,2,7,7-Tetramethyl-4,5-diphenyl-octadien-(3,5) (III) ... 

Molecules having only a sulfoxide function and no other acidic or basic site have been resolved through the intermediacy of metal complex formation. In 1934 Backer and Keuning resolved the cobalt complex of sulfoxide 5 using d-camphorsulfonic acid. More recently Cope and Caress applied the same technique to the resolution of ethyl p-tolyl sulfoxide (6). Sulfoxide 6 and optically active 1-phenylethylamine were used to form diastereomeric complexes i.e., (-1-)- and ( —)-trans-dichloro(ethyl p-tolyl sulfoxide) (1-phenylethylamine) platinum(II). Both enantiomers of 6 were obtained in optically pure form. Diastereomeric platinum complexes formed from racemic methyl phenyl (and three para-substituted phenyl) sulfoxides and d-N, N-dimethyl phenylglycine have been separated chromatographically on an analytical column L A nonaromatic example, cyclohexyl methyl sulfoxide, did not resolve. 

Figure 6.10. Rate constants for quenching of sensitizers by cis- and trans-stilbenes (open and filled circles, respectively). Sensitizers are as follows (1) tri-phenylene, (2) thioxanthone, (3) phenanthrene, (4) 2-acetonaphthone, (3) 1-naphthyl phenyl ketone, (6) crysene, (7) fluorenone, (8) 1,2,5,6-dibenzanthracene, (9) benzil, (10) 1,2,3,4-dibenzanthracene, (11) pyrene, (12) 1,2-benzanthracene, (13) benzanthrone, (14) 3-acetyl pyrene, (15) acridine, (16) 9,10-dimethyl-l,2-benzanthracene, (17) anthracene, (18) 3,4-benzpyrene.<57> Reprinted by permission of the American Chemical Society.

Snyder et al. [253] compared supercritical fluid chromatography with classical sonication procedures and Soxhlet extraction for the determination of selected insecticides in soils and sediments. In this procedure the sample was extracted with carbon dioxide modified with 3% methanol at 350atm and 50°C. An excess of 85% recovery of organochlorine and organophosphorus insecticides was achieved. These included Dichlorvos, Diazinon, (diethyl-2-isopropyl-6-methyl 4-pyrimidinyl phosphorothioate), Ronnel (i.e. Fenchlorphos-0,0 dimethyl-0-2,4,5-trichlorophenyl phosphorothioate), Parathion ethyl, Methiadathion, Tetrachlorovinphos (trans-2-chloro-l-(2,4,5 trichlorophenyl) vinylchlorophenyl-O-methyl phenyl phosphoroamidothioate), Endrin, Endrin aldehyde, pp DDT, Mirex and decachlorobiphenyl. 

TABLE 28. The most stable conformations of trans- and c -2,3,4,5,6,7-hexahydro-3,7-dimethyl-1 -phenyl-Iff-3-benzazonine (103 and 105) as calculated by MM2-80... 

This appears to be a rather mixed collection of compounds. We recognize three isox-azolines in the collection. However, the data for the last two species, the cis and trans isomers of 3-phenyl-2-isoxazolinedicarboxylic acid dimethyl ester from Reference 67, are suspect because the difference of 125 kJmol is implausible—the corresponding difference for the cis and trans butenedioic acid dimethyl esters from Reference 68 is but ca 30kJmol-. ... 

Another example occurs with cis- and mj/w-3,4-dimethyl-5-phenyloxazolidine. In the cw-com-pound the 4-methyl protons are shielded by 0.7 ppm compared to the trans-isomer due to the proximity of the phenyl ring96. 

Die Cyclisierung von optisch aktiven Alkenal-iminen nach diesem Schema kann zur enan-tio- und diastcreoselektiven Synthese von alkyl-substituierten Amino-cyclohexanen herangezogen werden, z. B. von (/ / )-trans-l-Amino-5,5-dimethyl-2-isopropyI-cyclohcxan ausgehend von 3-Methyl-citronellal und (7 )-l-Phenyl-cthyIaminI. 

HEXAHYDRO - 4a,5 - DIMETHYL - 2(3H) - NAPHTHALE-NONE and 2-TRIMETHYLSILYLOXY-1,3-BUTADIENE AS A REACTIVE DIENE DIETHYL trans -4-TRIMETHYL-SILYLOXY-4-CYCLOHEXENE-1,2-DICARBOXYLATE. Sulfur substitution also continues to be of high interest, and three preparations on sulfide synthesis are included BENZYL SULFIDE DIALKYL AND ALKYL ARYL SULFIDES NEOPENTYL PHENYL SULFIDE and UNSYMMETRICAL DIALKYL DISULFIDES sec-BUTYL ISOPROPYL DISULFIDE. 

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