Magnesium isopropyl- bromid

To a well stirred suspension of 9 g of sodium phenyl acetate and 2.4 g of magnesium turnings in 25 cc of anhydrous ether, a solution of 9.4 cc of isopropyl bromide in 50 cc of anhydrous ether are added. The mixture is refluxed for one hour (during which time propane is evolved) and then 5 cc of cyclopentanone in 25 cc of anhydrous ether are added dropwise. The mixture is then refluxed for one hour and poured over ice water containing some hydrochloric acid. The ether solution is separated and extracted with 200 cc of 5% sodium hydroxide. The alkaline solution on acidification gives the free acid which is filtered off, dried in a desiccator and recrystallized from a mixture of ethylene dichloride and petroleum ether. 

Isopropylmethylphenyl Carbinol. Prepare the Grignard reagent, as directed in section (A), from 5.0 g of isopropyl bromide, 1 g of magnesium, 10 ml of ether. To the Grignard reagent add 4.8 g of acetophenone. Decompose and extract with ether. The ether extract is dried with 0.5 g of anhydrous calcium sulfate and the ether removed as described above. It is then distilled under reduced pressure. The first fraction of about 1.0-1.5 g distills at 90-96° at 15 mm pressure. The second fraction, which is the carbinol, distills at 100-106° at 16 mm pressure. The yield is 2.4 g. 

Russian authors have applied the Ivanov reaction to 1,2 5,6-di-O-cyclo-hexylidene-a-D-n7)0-hexos-3-ulofuranose, which involves reacting phenylacetic acid, magnesium, and isopropyl bromide in tetrahydrofuran. The 3-ulose is then added to this preformed complex, when the addition of the phenylacetie acid side-chain occurs to give (14). 

Preparation of 4-aza-S-(N-methyl-4-piperidyll-10,11-dihydro-SH-dibenzo[a,d]cycloheptene-S-ol Add 17.4 g of N-methyl-4-chloropiperidine to a stirred mixture containing 3.2 g of magnesium, 20 ml of anhydrous tetrahydrofuran, 1 ml of ethyl bromide and a crystal of iodine. Reflux for two hours, cool to 30°-35°C and add a solution of 13 g of 4-aza-10,11 -dihydro-5H-dibenzo[a,d] cycloheptene-5-one in 25 ml of tetrahydrofuran. Stir for five hours, remove the solvent by distillation in vacuo and add 250 ml of ether. Add 100 ml of 10% ammonium chloride solution and extract the mixture with chloroform. Concentrate the chloroform solution to a residue and recrystallize from isopropyl ether obtaining 20 g of the carbinol,... 

Since sodium borohydride usually does not reduce the nitrile function it may be used for selective reductions of conjugated double bonds in oc,/l-un-saturated nitriles in fair to good yields [7069,1070]. In addition some special reagents were found effective for reducing carbon-carbon double bonds preferentially copper hydride prepared from cuprous bromide and sodium bis(2-methoxyethoxy)aluminum hydride [7766], magnesium in methanol [7767], zinc and zinc chloride in ethanol or isopropyl alcohol [7765], and triethylam-monium formate in dimethyl formamide [317]. Lithium aluminum hydride reduced 1-cyanocyclohexene at —15° to cyclohexanecarboxaldehyde and under normal conditions to aminomethylcyclohexane, both in 60% yields [777]. 

Abstract. Grignard reactions are of utmost importance in organic synthesis (Lee, 2005), and finding the prime conditions under which to conduct these reactions is really crucial to their usefulness. This work looks at the effects of time, and temperature on yield in the reaction of isopropyl magnesium bromide with 4-methoxyben-zaldehyde to produce l-(4-methoxyphenyl)-2-methylpropan-l-ol. The reaction was first run for 10 min at 25, 50, 75, and 80 °C. Next it was run at 80 °C for 10, 20, and 30 min (see Methods section for more details). Highest yields (85%) were obtained at 80 °C with 10-20 min reaction times. Utilizing conditions that optimize yields will improve the economic practicality of these reactions, and increase their usefulness as a synthetic tool. 

The stereoselective Horner-Wadsworth-Emmons reaction of aldehydes with 2-fluoro-2-diethylphosphonoacetic acid utilizing isopropyl magnesium bromide afforded (Z)-a-fluoro-a,j8-unsaturated carboxylates (42) as the major products in 81-98% yield [58] (Scheme 14). 

Corrected for 85.1 % optical purity of chiral imine. p Recorded at 22 °C. q Metalation with isopropyl magnesium bromide. 

Nitric acid. Sulfuric acid, N-Methylhydroxy acetamide Phosphorus oxytrichloride. Benzene, Neopentyl glycol. Pyridine, Petroleum ether. Ammonium fluoride Thiophosphorus trichloride. Benzene, Neopentyl glycol. Pyridine, Petroleum ether. Ammonium fluoride Nitric acid. Sulfuric acid. Glycerol, Magnesium sulfate Anhydrous hydrazine. Cyanogen bromide. Isopropyl alcohol. Sodium nitrite. Sodium bicarbonate. Copper nitrate trihydrate. Nitric acid. Diethyl ether... 

To prove this hypothesis a suitable substrate, l-diazo-3-methyl-3-[(E)-phenyldiazenyl]butan-2-one (42) was used. Methyl 2-(2-arylhydrazino)-2-methylpropanoate (39) reacting with a bulky Grignard reagent like isopropyl magnesium bromide gives 4,4-dimethyl-2-phenyl-l,2-diazeti-din-3-one 40 (87TL6577). Oxidation with ferf-butyl hypochlorite converts diazetidinone 40 into 2-methyl-2-(phenyldiazenyl)propanoyl chloride 41, which upon treatment with diazomethane affords the desired diazo ketone 42 (Scheme 8) (98ACE2229). 

---