Borohydride, dimethylamino

The sterically unbiased dienes, 5,5-diarylcyclopentadienes 90, wherein one of the aryl groups is substituted with NO, Cl and NCCHj), were designed and synthesized by Halterman et al. [163] Diels-Alder cycloaddition with dimethyl acetylenedicarbo-xylate at reflux (81 °C) was studied syn addition (with respect to the substituted benzene) was favored in the case of the nitro group (90a, X = NO ) (syrr.anti = 68 32), whereas anti addition (with respect to the substituted benzene) is favored in the case of dimethylamino group (90b, X = N(CH3)2) (syn anti = 38 62). The facial preference is consistent with those observed in the hydride reduction of the relevant 2,2-diaryl-cyclopentanones 8 with sodium borohydride, and in dihydroxylation of 3,3-diarylcy-clopentenes 43 with osmium trioxide. In the present system, the interaction of the diene n orbital with the o bonds at the (3 positions (at the 5 position) is symmetry-forbidden. Thus, the major product results from approach of the dienophile from the face opposite the better n electron donor at the (3 positions, in a similar manner to spiro conjugation. Unsymmetrization of the diene % orbitals is inherent in 90, and this is consistent with the observed facial selectivities (91 for 90a 92 for 90b). 

Methadone hydrochloride (600.0 mg,1.74 mmol) was dissolved in ethanol (10 ml) and the solution was stirred whilst sodium borohydride (3.47 mmol) was added portion-wise over a period of 5 min. When the addition was complete a spatula end of cerium (III) chloride heptahydrate was added. The resultant solution was allowed to stir at room temperature for 30 min then the ethanol was removed under reduced pressure. The residue was portioned between diethyl ether (40 ml) and water (40 ml). The aqueous layer was extracted with more diethyl ether (2 times 20 ml) and then the combined organics were washed with brine (40 ml) and dried (MgS04). The ether was removed under reduced pressure to leave 435.0 mg, (80%) of 6-dimethylamino-4,4-diphenyl-3-heptanol. 

Methoxycarbony-10-methylacridinium methosulphate Potassium borohydride Lithium aluminum hydride Phosphorus pentoxide l-Dimethylamino-2-chloroethane hydrochloride... 

To a suspension of the 3-[(dimethylamino)acetyl]-N-methyl-lH-indole-5-methanesulphonamide (46.5 mg) in 1-propanol (5 ml) was added sodium borohydride (62 mg). The reaction mixture was brought to reflux for a period of 3 h, then an additional quantity of borohydride (60 mg) was added. After refluxing for a further 1 h, the mixture was allowed to cool to room temperature and quenched with 2 N HCI (10 ml). The aqueous solution was washed with ethyl acetate (5 ml) then neutralized (NaHC03 solution) and extracted with ethyl acetate (3 x 15 ml). The combined extracts were concentrated in vacuo and the residue chromatographed to give the 3-[2-(dimethylamino)ethyl]-N-methyl lH-indole-5-methanesulphonamide as a gum (2 mg) which was shown by TLC. 

REDUCTION, REAGENTS Bis(N-methylpi-perazinyl)aluminum hydride. Borane-Di-methyl sulfide. Borane-Tetrahydrofurane. Borane-Pyridine. n-Butyllithium-Diisobu-tylaluminum hydride. Calcium-Amines. Diisobutylaluminum hydride. 8-Hydroxy-quinolinedihydroboronite. Lithium aluminum hydride. Lithium 9-boratabicy-clo[3.3.1]nonane. Lithium n-butyldiisopro-pylaluminum hydride. Lithium tri-j c-butylborohydride. Lithium triethylborohy-dride. Monochloroalane. Nickel boride. 2-Phenylbenzothiazoline. Potassium 9-(2,3-dimethyl-2-butoxy)-9-boratabicy-clo[3.3.1]nonane. Raney nickel. Sodium bis(2-methoxyethoxy)aluminum hydride. Sodium borohydride. Sodium borohy-dride-Nickel chloride. Sodium borohy-dride-Praeseodymium chloride. So-dium(dimethylamino)borohydride. Sodium hydrogen telluride. Thexyl chloroborane-Dimethyl sulfide. Tri-n-butylphosphine-Diphenyl disulfide. Tri-n-butyltin hydride. Zinc-l,2-Dibromoethane. Zinc borohydride. 

The new metallic hydrides are excellent reducing agents for carbonyl compounds. These hydrides now include lithium aluminum hydride, lithium borohydride, and sodium borohydride. The last reagent may be used in either aqueous or methanolic solutions. It does not reduce esters, acids, or nitriles and, for this reason, is superior for certain selective reductions. Other groups which are unaffected by this reagent include a,/S-double bonds and hydroxyl, methoxyl, nitro, and dimethylamino groups. ... 

Amino-l,2-dihydroacronycine (40 ) could be easily converted into variously substituted amines and amides. Treatment of 40 with formaldehyde and sodium borohydride afforded 2-dimethylamino-l,2-dihydroacronycine (42). Both aliphatic and aromatic amides were obtained from 4 upon treatment with acid anhydrides in pyridine. This latter reaction is exemplified by the preparation of 2-acetylamino-l,2-dihydroacronycine (43J and 2-benzoylamino-l,2-dihydroacronycine (44) using acetic anhydride and benzoic anhydride, respectively (53). 

DEHALOGENATION l,8-Bis(dimethylamino)napthalene. Lithium diphenylphosphide. Potassium hydridotetracarbonylferrate. Sodium-t-Butanol-Tetrahydrofurane. Sodium borohydride. Sodium iodide. Tri- -butyltin hydride. 

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