Diazomethane, diphenyl

Diphenyl diazomethane Benztropine mesylate a/l -Diphenyl-7.dimethylamino valeronitrile Aminopentamide Diphenylmethane... 

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... 

Reactions of cyclic tetrasulfides containing a heavier group 14 element, Tbt(Ar)MS4 (M=Ge, Ar=Mes or Tip M=Sn, Ar=Tip), with diphenyl diazomethane gives l,2,3,5-tetrathia-4-metallacyclohexanes, l,2,4,5-tetrathia-3-metallacyclohexanes, and l,2,4-trithia-3-metallacyclopentanes (Scheme 54) [52, 118-120],... 

Scheme 54 Reaction of cyclic tetrasulfides containing a heavier group 14 element with diphenyl diazomethane...

As was noted previously, Hine and Bailey (16, 17) have obtained correlation of rate data for the reaction of tra s-3-substituted acrylic acids and diphenyl-diazomethane with the Hammett equation. Bowden has reported correlation of rate data for the reaction of tra s-3-substituted acrylic acids with diphenyl-diazomethane (59) and the alkaline hydrolysis of trans-3-substituted methyl acrylates (69) with the Hammett equation. Sufficient data are available for nine sets of rate studies. The sets studied are reported in Table VIII. The results of the correlations are given in Table IX. Of the nine sets studied, seven gave... 

Water samples of 500-1000 mL are extracted and purified simultaneously through an SPE cartridge such as Carbograph-1, Cig and RP-18, usually followed either by HPLC with ultraviolet (UV) or photoconductivity detection or by GC/ECD. The acidic-type diphenyl ether herbicides are derivatized with diazomethane and various kinds of chloroformates and determined by GC and HPLC. 

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.

The difference in structure between 16 and 17 is readily understood in terms of the addition of strongly electron-donating substituents, but the contrast between 16 and 20 is less easily rationalized. Photolysis of 19 was carried out in HFIP (dielectric constant (e) = 16.75), while TRIR experiments with diphenyl diazomethane (22) were carried out in dichloromethane (e = 9.08), suggesting that a-lactone structure may be dependent on solvent polarity. 

Diphenylcyclopropane has been prepared in 24% yield by the Simmons-Smith reaction,2 in 78% yield by treatment of 3,3-diphenylpropyltrimethylammonium iodide with sodium or potassium amide,3 in 61% yield by reaction of 1,1-diphenyl-ethylene with dimethylsulfonium methylide,4 and in unspecified yields from 1,1-diphenylethylene by reaction with diazomethane followed by pyrolysis of the resulting pyrazoline or by reaction with ethyl diazoacetate followed by distillation of the corresponding acid over calcium oxide.5... 

Kinetic studies of the thermolysis of diazomethane were carried out by various authors. These experiments demonstrated that the decomposition of diazomethane was a first order reaction 41-43) Similar investigations of the p5n olysis of diphenyl-diazomethane in xylene or 1-methylnaphthalene also showed that the disappearance of diphenyl-diazomethane is a first order process. It may be concluded that a free carbene is involved in these reactions, in accordance with the following scheme ). 

In the photolysis of. -dibromo-diphenyl-diazomethane in toluene the geminate pair effect is observed 87). However, it is accompanied by the enhanced emission by the escape product 7. This means that the carriers of the original polarization were the free radicals, whose lifetime is obviously shorter than the nuclear relaxation time. 

Evident cases of abstraction/recombination mechanism are observed with phenylsubstituted carbenes. Diphenyl-diazomethane, which is photolyzed to give the triplet diphenyl-carbene, very readily abstracts a hydrogen atom from the benzyl group of toluene. The primarily formed radicals can now recombine to give a formal "insertion product — 1,1,2-triphenylethane — or they can recombine to form 1,1,2,2-tetraphenylethane and 1,2-diphenylethane... 

The photolysis of diphenyl-diazomethane in cis-jS-deutero-styrene, on the other hand, can be affected by dilution with hexafluorobenzene. The amount of trans-cyclopropane 49 is slightly larger, indicating that about 12% of the singlet carbene are still present in very dilute solutions (see Table 9). 

A second example of the use of ionic chiral auxiliaries for asymmetric synthesis is found in the work of Chong et al. on the cis.trans photoisomerization of certain cyclopropane derivatives [33]. Based on the report by Zimmerman and Flechtner [34] that achiral tmns,trans-2,3-diphenyl-l-benzoylcyclopropane (35a, Scheme 7) undergoes very efficient (0=0.94) photoisomerization in solution to afford the racemic cis,trans isomer 36a, the correspondingp-carboxylic acid 35b was synthesized and treated with a variety of optically pure amines to give salts of general structure 35c (CA=chiral auxiliary). Irradiation of crystals of these salts followed by diazomethane workup yielded methyl ester 36d, which was analyzed by chiral HPLC for enantiomeric excess. The results are summarized in Table 3. 

Af-Unsubstituted 1,2,4-diazaarsoles are directly alkylated by diphenyl diazomethane, diazo esters, sulfur ylides, and alkyl vinyl ethers <90TL7607, 95HAC403). 1-Alkyl-1,2,4-diazo-arsoles (12) (R = Me, CHPhj) react with dimethylsulfoxonium yhde to give bicyclic arsiranes (13) (Equation (1))... 

The 3,3,5,5-tetrasubstituted 1,2,4,3-trithiagermolane (318) was obtained quantitatively by desulfurization with P(NMe2)3 of the l,2,4,5-tetrathia-3-germacyclohexane (402) which is one of the products formed from the corresponding 1,2,3,4,5-tetrathiametallolane (388) and diphenyl-diazomethane <91TL6143>. 

Diphenyl-4-nitro-l-oxo-butan wird auf diese Weise aus 1,3-Diphenyl-3-oxo-propen in Gegenwart von Kaliumfluorid/Diazomethan in Toluol oder Acetonitril (3-4 d) zu 50 100% erhalten3. 

Dipolar cycloadditions to azepines are confined to diazomethane and diphenyl-nitrilimine. The former reagent, depending on the nature of the substituents on the H-azepine, either adds at the 4,5-bond to yield pyrazolines (160) or traps the benzeneimine tautomer of the azepine as the bis-pyrazoline (Section 5.16.2.4) (76CB3505). A pyrazoline is also the product from the addition of diphenylnitrilimine to 5//-dibenz[i,/]azepine (B-67MI51600). 

---