The thermal decomposition of diazirines: 3-(3-methyldiazirin-3-yl)propan-1-ol and 3-(3-methyldiazirin-3-yl)propanoic acid
Abstract
The thermolyses of 3-(3-methyldiazirin-3-yl)propan-1-ol (1) and 3-(3-methyldiazirin-3-yl)propanoic acid (2) have been studied in solution over the temperature range 96–125 °C. The reactions are unimolecular and fit linear Arrhenius plots with K(1)= 1013.85 ± 0.69exp[–31.80 ± 1.21 kcal mol–1/RT]s–1 and K(2)= 1012.38 ± 0.43exp[–29.26 ± 0.75 kcal mol–1/RT]s–1
The major products are the alkenes derived from the corresponding carbenes MeCH2CH2CH2OH (3) and MeCH2CH2CO2H (4). The new rate data, taken together with previous work, tend to confirm that diazirine thermolysis involves ring opening to a ‘complex’ followed either by nitrogen loss or by isomerization to a diazo compound. Whereas (1) gives no product of closure onto oxygen, the acid (2) affords about 5%γ-valerolactone.