Bis diazomethane

Diazomethan Bis-[4-brom-phenyl]-lV/lb, 108/E14b, 1004 (Hydra-zon-Oxid.)... 

DIAZOMETHANE, BIS(TRIFLUORO-METHYL)-, 50, 6 Diazomethane, dideuterio-, 53, 38 2-DIAZOPROPANE, 50, 5, 27 DIBENZO-18-CROWN-6 POLYETHER, 52, 66... 

Syntheses of 3,4-bis(trifluoromethyl) 131 and 3,4,5-(tris)trifluoromethylpyrazole 133 were reported in the second half of the past century [72], These procedures involved the use of gaseous starting materials such as diazomethane, bis(trifluoromethyl) acetylene, or trifluoromethyldiazomethane (Scheme 43). Recently, two practical syntheses to 131 and 133, based on the transformation of the carboxylic group into the trifluoromethyl group by sulphur tetrafluoride (SF4), were reported (Scheme 43) [73], These procedures allowed the gram-scale preparation of 131 (30 % overall yield from commercially available 130) and 133 (36 % overall yield from commercially available 132). Physical properties such as A Tf-acidities or fluorescence were determined for both compounds. 

Decane-1 10-dicarboxylic acid from sebacic acid. Convert sebacic acid into the acid chloride by treatment with phosphorus penta-chloride (2 mols) and purify by distillation b.p. 146-143°/2 mm. the yield is almost quantitative. Dissolve the resulting sebacoyl chloride in anhydrous ether and add the solution slowly to an ethereal solution of excess of diazomethane (prepared from 50 g. of nitrosomethylurea) allow the mixture to stand overnight. Remove the ether and excess of diazomethane under reduced pressure the residual crystalline 1 8-bis-diazoacetyloctane weighs 19 -3 g. and melts at 91° after crystaUisation from benzene. 

The reaction of cyclohexene with the diazopyruvate 25 gives unexpectedly ethyl 3-cyclohexenyl malonate (26), involving Wolff rearrangement. No cyclo-propanation takes place[28]. 1,3-Dipolar cycloaddition takes place by the reaction of acrylonitrile with diazoacetate to afford the oxazole derivative 27[29]. Bis(trimethylstannyl)diazomethane (28) undergoes Pd(0)-catalyzed rearrangement to give the A -stannylcarbodiimide 29 under mild conditions[30]. 

In the latter process Dieckmann cyclization of diester (11) using high dilution conditions failed. However, A-homo-5a-cholestan-3-one (5b) identical to the product of diazomethane ring enlargement of (lb) was obtained in 35 % yield when diester (11) was hydrolyzed to the bis-homo diacid and this converted to the thorium salt and pyrolyzed. 

Bis(lrifluoromethyl)oximes also are highly reactive dipolarophiles, as evidenced by the facile regiospecific addition of diazomethane [32] (equation 28)... 

Reactions offluorinated dipoles. In recent years, much effort has been devoted to the preparation of tnfluoromethyl-substituted 1,3-dipoles with the goal of using them to introduce trifluoromethyl groups into five-membered nng heterocycles Fluorinated diazoalkanes were the first such 1,3-dipoles to be prepared and used in synthesis A number of reports of cycloadditions of mono- and bis(tnfluo-romethyl)diazomethane appeared prior to 1972 [9] Other types of fluonne-substi-tuted 1,3-dipoles were virtually unknown until only recently However, largely because of the efforts of Tanaka s group, a broad knowledge of the chemistry of tnfluoromethyl-substituted nitrile oxides, nitnle imines, nitnle ylides, and nitrones has been accumulated recently... 

On reaction of methyl trifluoropyruvate with phosphorus pentachlonde 1,1,2,2 tetrachloro-3,3,3-trifluoro-l-methoxypropane IS obtained [273] Hexafluo-roacetone hydrazone is oxidized to bis(tnfluoromethyl)diazomethane upon tieat-ment with phosphorus pentachlonde [274]... 

Final structure determination of the monomethyl derivatives was made possible only on performing straightforward syntheses of the compounds, analogous to syntheses of allantoxaidine. The 1-methyl (19) and 3-methyl (20) derivatives were prepared by cyclization of 1- and 3-methyl biuret,respectively. The 3-methyl derivative was also obtained by cyclization of A ,A -bis(methylcarbamyl)formami-dxne. The 1-methyl derivative was the same as the product obtained by Biltz on methylation of silver salt of allantoxaidine with methyl iodide. The same product is formed primarily during methylation of dioxotriazine with diazomethane. An excess of this agent produces the expected 1,3-dimethyl derivative (21). These results of alkyl-... 

Bis(alkynyl)-l//-pyrazoles are also obtained by the same procedure. The reaction of (Z)-enediyne sulfones with diazomethane gives bis(alkynyl)-3//-... 

Diacetylene reacts with diazomethane in an ether solution at 0°C to form 5-ethynylpyrazole (80) (65ZOR610). The second diazomethane molecule adds to the remaining triple bond much more slowly. The bis adduct, 5,5 -dipyrazole (81), was isolated in 35% at a 1 2 diacetylene diazomethane molar ratio. 

Bi Methylation of 8-Hydroxypsoralen 115 mg of 8-hydroxypsoralen was dissolved in 10 ml absolute methanol, an excess of diazomethane dissolved in ether was added and the mixture allowed to stand at room temperature with occasional stirring for 3 hours. The next day the reaction mixture was reduced in volume to 3 ml by evaporation on the steam bath and the concentrate was held in a refrigerator overnight. The next day, fine needles (80 mg) of 8-methoxypsoralen were filtered from the solution. The compound had a MP of 145° to 146°C and was obtained in a yield of 65% of theory. 

Diphenyl-diazomethan liefert bei der Elektrolyse an Platin in DMF/Tetrabutylammo-niumperchlorat Diphenylmethan, Amino-diphenyl-methan und Benzophenon-azin. Bei hohcn negativen Potentialen (—1,9 bis —2,2 V) und niedriger Ausgangskonzentration iiberwiegt Diphenylmethan (bis 51% d.Th.) das Azin dominiert erwartungsgemaB bei... 

The reaction of bis(trifluoromethyl)diazomethane with either Ni(CNBu )4 or [Pd(CNR)2] (R = Bu, Cy), also gave interesting complexes (XL) the structure of an analogous species, Pt(PPhj)2(CF3)4C2N2, was determined by X-ray crystallography (43). 

Charrette and Lebel [24] developed a catalytic enantioselective cyclopropa-nation of trans-cinnamate esters with diazomethane. Their procedure involves an argon-flow-mediated diazomethane addition, leading to high yields (up to 80%) in products with up to 80% ee, by using the bis(oxazoHne) arising from phenylglycinol (Scheme 10). 

Some other groups have studied the opportimity to enhance the diastere-oselectivity of the transformation using the usual copper-bis(oxazohne) catalysts but modifying the carbene source. France et al. [25] observed that the use of (trimethylsilyl)diazomethane associated with a bis(oxazoline) and [Cu(CH3CN)4]PF6 as catalyst precursor allowed the formation of the trans isomer with high yield and selectivity, probably due to the steric bulk of the trimethylsilyl group. 

Figure 4.2. TRIR difference spectra averaged over the timescales indicated following 266 nm photolysis of (a) diphenyl diazomethane (3.6mM) and (b) bis-(4-methoxyphenyl)-diazomethane (1.1 mM) in C02-saturated dichloromethane. Reprinted with permission from B. M. Showalter and J. R Toscano, J. Phys. Org. Chem. 2004,14,743. Copyright 2004, John Wiley Sons Limited.

Interaction of diazomethane with bis(trimethylsilylamino)mercury gives the polymeric explosive solid. 

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