Pyrazole 1.3- dimethyl-4-bromo

When methylene chloride was used as a solvent, it was found that 28 are obtained in minor amounts, while the dominating product is the -coordinated chloro-carbyne species [(> -Tp )Mo(CO)2(=CCl)], whose yield increases abruptly with substitution in the pyrazol-l-yl fragments (3-methyl-, 3,4,5-trimethyl-, and 3,5-dimethyl-4-chloro derivatives) [90AX(C)59,95JCS(D) 1709]. The tungsten analog can be prepared similarly. The chlorocarbyne molybdenum complex follows also from the reaction of the parent anion with triphenylsulfonium cation but conducted in dichloromethane. The bromo- and iodocarbyne derivatives are made similarly. 

Oxidation of organic substrates. This hydroperoxide converts 2,3-dimethyl-2-butcne into tetramethylethylene oxide with simultaneous formation of 3-bromo-4,5-dihydro-5-hydroxy-4,4-dimethyl-3,5-diphenyl-3H-pyrazole (2). Dialkyl olefins, however, are not epoxidized by I. Enol ethers are converted to a variety of epoxide rearrangement products.2... 

In the case of 5-bromo-3,4-dimethyl-l-phenyl-l/f, 6//-pyrano[2,3-c]pyrazol-6-one (59), mixed acid nitration results not only in para substitution in the phenyl ring, but also in ipso attack at the 5-position to yield... 

Parallel i/wo-ni (ration at position 4 and nitration at position 5 of the pyrazole ring were also observed during the action of the sulfuric-nitric acid mixture on 1,3-dim-ethyl-4-bromopyrazole [369], The released bromine cation partly brominates the initial reagent with the formation of l,3-dimethyl-4,5-dibromopyrazole. The latter is subsequently transformed into l,3-dimethyl-5-bromo-4-nitropyrazole (see the Scheme later). The nitration of l,3-dimethyl-4,5-dibromopyrazole leads to the formation of l,3-dimethyl-5-bromo-4-nitropyrazole and l,3-dimethyl-4-nitropyrazole [369] (Scheme 48). 

A similar preference for cis- or emfo-products is generally observed in the reactions of thermally generated chloro(trichloroethenyl)carbene with a large variety of olefins (see Vol. E 19b, p 740)11. The alkynyl-substituted earbene 4 obtained by photolysis of 5-bromoethynyl-3,3-dimethyl-3//-pyrazole adds exo selectively to 3-cyclohexenone to give an 80 20 mixture of 7-bromo-7-(4-methyl-3-penten-l-ynyl)bicyclo[4.1.0]heptan-3-one (5/6)12. The reaction of chlorophenylcarbene and cyclohexene affords 7-chloro-7-phenylbicyclo[4.1.0]heptane with moderate endo preference (see Vol. E19b, p984), i. 

Cl7H1GN2O2, 4,5-Diphenyl-5-methoxycarbonyl-2(E)-pyrazoline, 43B, 279 C17H17BrN202, 3-Bromo-4,5-dihydro-5-hydroperoxy-4,4-dimethyl-3,5-di-phenyl-3H-pyrazole, 46B, 214... 

S)-(l-(3-(l,3-dimethyl-lH-pyrazol-5-yl)benzyl)pyrrolidin-2-yl)methanol To a 2-dram, round-bottom vial was added sequentially 3-formylphenyl MIDA boronate (0.4 M (THF suspension), 0.5 mL, 0.2 mmol), sodium triacetoxyborohydride (0.8 M (THF suspension), 0.5 mL, 0.4 mmol) and (5)-Prolinol (0.8 M (THF), 0.5 mL, 0.4 mmol), and the reactions were shaken at ambient temperature for 18 h. To the reaction vial was added a solution of aqueous K2CO3 (2 M, 1 mL, 2 mmol) and the reaction was then transferred to a 2-5 mL microwave vial containing 5-bromo-l,3-dimethyl-l//-pyrazole (0.4 mmol). To the vial was added a solution of PEPPSI-IPr in MeCN (0.1 M, 10 pmol), and the vials were irradiated in a microwave reactor at 150 °C for 20 min and analyzed by high-profile liquid chromatography (HPLC)-mass spectrometry (MS). To the microwave vial was added... 

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