73764-14-4Relevant academic research and scientific papers
7. Substituent and Isotope Effects on the Hydrolysis Rates of 2-Aryl-2-diazocarboxylic Esters
Bui-Nguyen, Mai-Huong,Dahn, Hans,McGarrity, John F.
, p. 63 - 75 (1980)
The overall kinetic solvent isotope effects on the acid catalyzed hydrolysis of a series of 2-diazo-2-carboxylic esters ArCN2COOCH3, and one 2-aryl-2-diazocarboxamide C6H5CH2CON(CH3)2 very inversely with the reactivity of the substrate, between limits of 3.14 and 1.46.A linear Hammett plot for the hydrolysis rates of the α-diazocarboxylic esters indicates that there is no mechanistic change for the hydronium-ion-catalyzed reaction.The relation between hydrolysis rate and buffer acid concentration deviates from linearity for high values of the latter.It is shown on the basis of the solvent isotope effects for the non-linear region that this deviation does not stem from a mechanistic change caused by the buffer base component.The specific salt effects on the general acid-catalyzed reaction are discussed.
Diazo-Transfer Reaction with Diphenyl Phosphorazidate
Villalgordo, Jose M.,Enderli, Adelheid,Linden, Anthony,Heimgartner, Heinz
, p. 1983 - 1998 (2007/10/02)
Diphenyl phosphorazidate (DPPA) was used as the azide source in a one-pot synthesis of 2,2-disubstituted 3-amino-2H-azirines 1 (Scheme 1).The reaction with lithium enolates of amides of type 2, bearing two substituents at C(2), proceeded smoothly in THF at 0 degree C; keteniminium azides C and azidoenamines D are likely intermediates.Under analogous reaction conditions, DPPA and amides of type 3 with only one substituent at C(2) gave 2-diazoamides 5 in fair-to-good yield (Scheme 2).The corresponding 2-diazo derivatives 6-8 were formed in low yield by treatment of the lithium enolates of N,N-dimethyl-2-phenylacetamide, methyl 2-phenylacetate, and benzyl phenyl ketone, respectively, with DPPA.Thermolysis of 2-diazo-N-methyl-N-phenylcarboxamides 5a and 5b yielded 3-subdtituted 1,3-dihydro-N-methyl-2H-indol-2-ones 9a and 9b, respectively (Scheme 3).The diazo compounds 5-8 reacted with 1,3-thiazole-5(4H)-thiones 10 and thiobenzophenone (13) to give 6-oxa-1,9-dithia-3-azaspironona-2,7-dienes 11 (Scheme 4) and thiirane-2-carboxylic acid derivatives 14 (Scheme 5), respectively.In analogy to previously described reactions, a mechanism via 1,3-dipolar cycloaddition, leading to 2,5-dihydro-1,3,4-thiadiazoles, and elimination of N2 to give the 'thiocarbonyl ylides' of type H or K is proposed.These dipolar intermediates with a conjugated C=O group then undergo either a 1,5-dipolar electrocyclization to give spiroheterocycles 11 or a 1,3-dipolar electrocyclization to thiiranes 14.
