Diazomethane: Methane, diazo

The only other esterification method which rivals the present procedure in convenience, mildness of conditions, selectivity, and yield js the preparation of methyl esters wdth diazomethane [Methane, diazo-] 10 Esterification with trialkyloxonium salts, however, allows... 

Diazomethane [Methane, diazo-], 62 Diethyl sulfate [Sulfuric acid, diethyl ester], 48... 

Mesityl isocyanide, 41,103 Methane, diazo-, 41,16 see also Diazomethane... 

Diazo-4-phenyl-2-butanone 2-Butanone, 1 -diazo-4-pihenyl- (8,9) (10290-42-3) Diazomethane Methane, diazo- (8,9) (334-88-3)... 

Compounds containing the neutral (formally zwitterionic) group =N2 attached to the C-atom are named by adding the prefix di2izo to the name of the parent compound (Rule 931.4, e. g. diazomethane, ethyl diazoacetate). Unfortunately diazo compounds is not an entry in the General Subject Index of Chemical Abstracts, Diazomethane is found in the Chemical Substance index under Methane, diazo- . 

Sodium acid methanearsonate Methane base. See Bis (p-dimethylaminophenyl) methane Methane, bis (2-(2-butoxyethoxy) ethoxy)-. See Butylcarbitol formal Methanebis (N,N -(5-ureido-2,4-diketotetrahydroimidazole)-N,N-dimethylol). See Imidazolidinyl urea Methane, bromochloro-. See Bromochloromethane Methane, bromochlorodifluoro-. See Bromochlorodifluoroemethane Methane, bromodichloro-. See Bromodichloromethane Methane, bromotrifluoro. See Trifluorobromomethane Methanecarbonitrile. See Acetonitrile Methanecarboxamide. See Acetamide Methanecarboxylic acid. See Acetic acid Methane, chloro-. See Methyl chloride Methane, chlorodibromo-. See Chlorodibromomethane Methane, chlorofluoro-. See Chlorofluoromethane Methane, compressed. See Methane gas, Methane cyanine. See Malononitrile Methane, diazo-. See Diazomethane Methanedicarbonic acid Methanedicarboxylic acid. See,Malonic acid Methanedicarboxylic acid, diethyl ester. See Diethyl malonate... 

Ketenes rarely produce [3+ 2]-cycloaddition products with diazo compounds. The reaction possibilities are complex, and nitrogen-free products are often obtained (5). Formation of a cyclopropanone represents one possibihty. Along these lines, the synthesis of (Z)-2,3-bis(trialkylsilyl)cyclopropanones and (Z)-2-trialkylsilyl-3-(triethylgermyl)cyclopropanones from diazo(trialkylsilyl)methanes and appropriate silyl- or germylketenes has been reported (256,257). It was found that subsequent reaction of the cyclopropanone with the diazoalkane was not a problem, in contrast to the reaction of diazomethane with the same ketenes. The high cycloaddition reactivity of diazomethylenephosphoranes also extends to heterocumulenes. The compound R2P(C1)=C=N2 (R = N(/-Pr)2) reacts with CS2, PhNCO and PhNCS to give the corresponding 1,2,3-triazole derivative (60). 

The 3//-l,2,4-diazaphospholes formed from the reaction of diazomethane and its monosubstituted derivatives (R CH=N2 R = H, alkyl, aryl, acyl, phosphoryl) could not be isolated due to a rapid 1,5-H shift leading to 27/-l,2,4-diazaphospholes 227. When diazo(trimethylsilyl)methane or [bis(diisopropylamino)phosphino]dia-zomethane was used, the l,5-SiMe3 [or PR2, R = N(/-Pr)2] shift completely dominates over the H shift (289,290). In the case of open-chain or cyclic a-diazoketones, cycloadducts 228 cannot be isolated due to rapid acyl shifts giving 229 and ultimately 230 (289). This transformation offers a versatile method to prepare [h]-fused 1,2,4-diazaphospholes from cyclic a-diazoketones and phos-phaalkynes (289). 

To a solution of 0.200 g. (0.515 mmole) of dry dihydrocholesterol (Note 1) in 10 ml. of methylene chloride contained in a 50-ml. Erlenmeyer flask is added 0.3 ml. of a catalyst stock solution containing 0.0016 ml. (0.018 mmole) of concentrated fluoboric add (Note 2) in 3 1 anhydrous diethyl ether-methylene chloride (Note 3). The solution is swirled, and a 0.45M solution of diazo-methane (Note 4) in dry methylene chloride is added from a buret (Note 5) at a rate of about 2 ml. per minute. The yellow color of diazomethane disappears rapidly on contact with the reaction mixture and nitrogen is vigorously evolved. When about 3 ml. of diazomethane solution has been added, the reaction becomes sluggish. The yellow color persists for several minutes after the total amount of 3.9 ml. of diazomethane solution (1.76 mmoles) has been added (Note 6). After 1 hour the reaction mixture is filtered to remove a small amount of amorphous polymethylene, which is washed with methylene chloride. The washings are combined with the methylene chloride solution, washed with 5 ml. of saturated aqueous sodium bicarbonate, with three... 

Diazomethane is highly recommended as a mild and efficient reagent for the preparation of methyl esters of N -protected amino acids or peptides.Diazo(trimethylsilyl)-methane is reported to be a safer alternative to the volatile, toxic, and explosive diazomethane in organic syntheses. 

Aldehydes and ketones can be converted to their homologs with diazo-methane. ° Several other reagents are also effective, including MesSil, and then silica gel, or LiCH(B-0CH2CH20-)2- With the diazomethane reaction. 

Diazoethylbenzene of Methylphenyl-diozo-methane [called (a-Diazo-athyl)-benzol or Methyl-phenyl-diazomethan in Ger], C5H5.C(N. CH3 mw 132.16, N 21,20% ... 

Several different methods have been employed for the preparation of diazo(trimethylsilyl)meth-ane (1). At present, the best synthetic method seems to be the diazo transfer reaction between diphenylphosphoryl azide and (trimethylsilyl)methylmagnesium chloride.However, the product often contains (chloromethyl)trimethylsilane and hexamethyldisiloxane as impurities. This method can also be employed for the synthesis of diazo(triethylsilyl)methane and diazo(di-ethylmethylsilyl)methane. The diazo transfer reaction can also be carried out with (trimethyl-silyl)methyllithium and tosyl azide. Other methods are the silylation of diazomethane with (trimethylsilyl)trifluoromethanesulfonate or chloro(trimethyl)silane and the base-induced cleavage of A-nitroso-A-[(trimethylsilyl)methyl]urea or the related carbamate or acet-amide.2° =... 

Bis(diisopropylamino)phosphanyl(trimethylsilyl)diazomethane 6, easily available by treatment of chlorobis(diisopropylamino)phosphane with lithiated diazo(trimethylsilyl)methane, provides upon flash thermolysis at 250"C the so-called stable carbene 7.38,39,40 behaves partly as a nucleophilic carbene and reacts only with electron-deficient alkenes such as methyl propenoate or diethyl fumarate under cyclopropanation." In the former case only the Z-isomer 8 is formed. Cyclopropane 9 is thermally unstable and is, therefore, oxidized in situ at the phosphorus atom with elemental sulfur to provide cyclopropane 10, Cyclopropanes 8 and 9 are also generated from the diazo compound 6 and the appropriate alkene by photolysis." ... 

Diazo-l,3-dicarbonyl-Verbindungen < Diazo-ketonc < Diazo-essigsaure-ester < Diazo-diphenyl-methan Diazomethan < Diazoethan... 

---