BENZENE, 1- 2- IODO-1.4-DIMETHYL

The condensation of 4-ethynyl-1,3-dimethyl-5-aminomethylpyrazole with iodo-benzene in the standard conditions of the Heck-Sonogashira reaction caused no complications and the yield of disubstituted acetylene was 87% (86TH1) (Scheme 68). 

Crich and Rumthao reported a new synthesis of carbazomycin B using a benzeneselenol-catalyzed, stannane-mediated addition of an aryl radical to the functionalized iodocarbamate 835, followed by cyclization and dehydrogenative aromatization (622). The iodocarbamate 835 required for the key radical reaction was obtained from the nitrophenol 784 (609) (see Scheme 5.85). lodination of 784, followed by acetylation, afforded 3,4-dimethyl-6-iodo-2-methoxy-5-nitrophenyl acetate 834. Reduction of 834 with iron and ferric chloride in acetic acid, followed by reaction with methyl chloroformate, led to the iodocarbamate 835. Reaction of 835 and diphenyl diselenide in refluxing benzene with tributyltin hydride and azobisisobutyronitrile (AIBN) gave the adduct 836 in 40% yield, along with 8% of the recovered substrate and 12% of the deiodinated carbamate 837. Treatment of 836 with phenylselenenyl bromide in dichloromethane afforded the phenylselenenyltetrahydrocarbazole 838. Oxidative... 

This latter equation correctly predicts the rates at which 1-iodo-naphthalene quenches triplet naphthalene in several fairly viscous solvents.165 It also correctly predicts the rate at which 2,5-dimethyl-2,4-hexadiene quenches triplet valerophenone in cyclooctane if the ketone s triplet lifetime is the same as that estimated from quenching experiments and from the flash spectroscopically measured rate constant for diffusion-controlled quenching in benzene.183... 

The analogues [menthyloxy(tosyloxy)iodo]benzenes, with both (+) and (-) forms of menthol, in their reactions with non-symmetric sulphides caused considerable asymmetric induction hydrolysis of their salts afforded sulphoxides of high optical purity [52]. By using A-phenyliodonio tosylates of benzamide (and some other similar derivatives from different amides, Section 7.4.1) dimethyl sulphide was converted into amidosulphonium tosylates which can serve as the precursors of sulphilimines [51] ... 

Equally, a 1.5 1 mixture of cis- and frans- 1,3-dibromo propene reacts with sodium dimethyl methylmalonate to furnish the vinyl bromo derivative 79 in excellent yield, which in turn is transformed in a one-pot fashion to a 1.5 1 mixture of enyne 80 or the corresponding Suzuki products 81 and 82 (Scheme 24). Interestingly, (( )-3-bromo-propenyl)-tributylstannane furnishes the vinyl stannane 83 upon allylic substitution that instantaneously is subjected to the conditions of a Stille coupling with iodo benzene to give the sequence s product 84 in 68% yield (Scheme 25). 

Other iodo complexes have been isolated containing 1,2-bis(dimethyl-arsino)benzene (181), bis(diphenylphosphino)methane and 1,2-bis-(diphenylphosphino)ethane (237), 2,9-dimethyl-1,10-phenanthroline... 

C12H18 1 -tert-butyl-3,5-dimethyl benzene 98-19-1 15.727 187.990 1,2 24801 C12H23I trans-1 -iodo-1 -dodecene 66553-46-6 16.428 245.387 1,2... 

TrinitTO-l, 3-dime thylbenzene, prisms (from ale), d 1.494 at 19° v si sol in ale can be prepd by nitrating 5-nitro-l,3-dimethyl-benzene, 4,5-dinitro-l,3-dimethylbenzene or 4-iodo-5-nitro-1,3-dimethylbenzene with mixed acid (Ref 2)... 

Ru(Tp)(PPh3)(MeCN)2]PFg has been employed as catalyst to produce l-iodo-2-naphthol in DMF and 2-iodobenzo[d]oxepin in benzene from l-(2/-iodoethynylphenyl)-2-propyloxirane. The solvent-dependent chemoselectivity has been ascribed to a solution equilibrium between ruthenium-Tt-iodoalkyne and ruthenium-2-iodovinylidene intermediates.66 The same ruthenium phosphine complex has been efficiently employed as catalyst in the nucleophilic addition of water, alcohols, aniline, acetylacetone, pyrroles, and dimethyl malonate to unfunctionalized enediynes that yielded functionalized benzene products in good yields (Fig. 8.6).67 [Ru(Tp)-(PPh3)(MeCN)2]PFg has been also found very active in catalytic benzannulation of l-phenyl-2-ethynylbenzenes in dichloroethane to afford phenanthrene.68... 

BENZENE, 2-iodo-l,4-dimethyl-, 55, 70 Benzene, 4-isopropyl-l-pentyl-, 55, 10 Benzene, nitro-4-chloro-, 55, 94... 

Restricted Internal Rotation of Several Symmetric Tops. The tables of thermodynamic functions for an internal rotation of a single symmetric top may be used for several symmetric tops [with moments of inertia calculated from equation (20)] provided both potential energy and kinetic energy cross-terms between the tops can be neglected. Both assumptions have been generally made in calculations for molecules with several tops. Where there are reliable calorimetric data at one or more temperatures, the tables have been used to calculate appropriate potential barriers. Using this procedure thermodynamic contributions have been calculated for propane, 2-methylpropane, 2,2-dimethylpropane, cis-but-2-ene, rm a -but-2-ene, isobutene, o-xylene, > m-xylene, p-xylene, 1,2,3-trimethylbenzene, > 1,2,4-trimethylbenzene, dimethyl sulphide,2-chloro-2-methylpropane, and dimethyl-amine. In several cases thermodynamic contributions have been calculated using potential barriers estimated from those of related molecules. Examples of this procedure are found in calculations for 2-fluoro-2-methylpropane, 2-chloropropane, 2-bromopropane, 2-iodopro-pane, 2,2-dichloropropane, 2-bromo-2-methylpropane, 2-iodo-2-methylpropane, 1,3,5-trimethylbenzene, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, 1,2,3,4-tetramethylbenzene, pentamethyl-benzene, and hexamethylbenzene. ... 

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