Lukose Mathew - Academia.edu (original) (raw)

Papers by Lukose Mathew

Research paper thumbnail of The Α-Hydroxyalkyl Diazenes and the Α-Hydroperoxyalkyl Diazenes as Sources of Radicals for the Kinetic Studies of Some Radical-Molecule Reactions in Solution

ABSTRACf a-Hydroxyalkyl diazenes and a-hydroperoxyallcyl diaz.enes are known for a long time as i... more ABSTRACf a-Hydroxyalkyl diazenes and a-hydroperoxyallcyl diaz.enes are known for a long time as initiators for fn:e radical polymerization. Their application as suitable radical precursors for kinetic studies such as the radical-molecule and radical-radical reactions are not well-exploited. This thesis deals mainly with the rate constants for a number of radical-molecule reactions studied by generating radicals in solution from suitable radical precursors mentioned above. The initiation mechanism for the decomposition of a-hydroxyalkyl diazenes was also investigated. Alkyl(l-hydroperoxy-l-methylethyl)diazenes (154) [(CH 3 hC(OOH)N=NR]:• a. R = c-~Hs-CH2; b, R = c-GJHs-CD:z; c, R = CH2=CH-(0I2~-CH2; d, R =CH 3 (CH 2 h-CH 2 and phenyl(l-hydroperoxy-l-methylethyl)diaz.ene (l54e) were prepared in solution by autoxidation of the corresponding hydrazones of acetone. They (l54a-e) were convened to the corresponding alkyl(l-hydroxy-l-methylethyl}diazene (155a-d) and phenyl(1-hydroxy-l-methylethyl}diazene (155e) by reduction with biphenyl phosphine. The radical chain decomposition of 5-hexenyl(1-hydroxy-I-methylethyl)diaz.ene (155c) in carbon tetrachloride and product analysis gave the rate constant for chlorine abstraction by the S-hexenyl radical. The rate constant was calculated from the product composition and the known rate constant for the cycli7ation of the S-hexenyl radical. For the tcmperature rangc 274-353 K, the rate constant is given by 10g(kdM•l s•l) = (8.4 ± 0.3)-(6.2 ± 0.4)/0, where 9 = 2.3 kcaVmol, which leads to ka¢C) =7.2 x 103 M•l s•l. Rearrangement of cyclopropylmethyl radical to the but-3-enyl radical was used to clock brominc and iodine abstraction reactions from a number of substrates. Cyclopropylmethyl(l-hydroxy-l-methylethyl}diazene (155a) was used as the source for yclopropylmcthylradical. Decomposition of lSSa in hexafluorobenzene or in dichloromethane containing bromotrichloromcthan~and product analysis enabled the calcv 1 .ation of the rate constant (leDr) for bromine abstraction by cyclopropylmcthyl radicals from bromottichloromcthanc.

Research paper thumbnail of Rate constants for abstraction of bromine from bromotrichloromethane by butyl, cyclopropylmethyl, and phenyl radicals in solution

Canadian Journal of Chemistry, 1988

The radical chain decomposition of cyclopropylmethyl (I-hydroxy-1-mcthylethy1)-diazcnc ((CH3)2C(O... more The radical chain decomposition of cyclopropylmethyl (I-hydroxy-1-mcthylethy1)-diazcnc ((CH3)2C(OH)N=NCHI-<1 1) at 253-341 K in hexafluorobenzene or in dichloromethane solution containing brornotrichloromethane affords cyclopropylmethyl bromide, 4-bromo-I-butene, I-bromo-5,5,5-trichloro-2-pentene, and 3,5-dibromo-I, I, I-trichloropcntane from the cyclopropylmethyl portion of 1. Other major products are nitrogen, acetone, and chloroform. The rate constant for formation of cyclopropylmethyl bromide by attack of cyclopropylmethyl free radicals from 1 at bromine of BrCCI, (kyy) was calculated from the product composition using the known rate constant for rearrangement of cyclopropylmethyl radicals to 3-buten-I-yl radicals. At 25"C, kTF = 6.5 X lo8 M-I s-I and the temperature dependence is given by log (ksm/M-I s-) = (10.6 5 0.3)-(2.4 C 0.4)/0, where 0 = 2.3R~kcal/mol-l. Non-chain decompositionof (CH3),C(OH)N=N-R(2, R = Bu, and3, R = Ph) in the presence of excess 1 ,I ,3,3-tetramethylisoindolin-2-yloxyl (4) and bromotrichloromethane afforded BuBr and PhBr, respectively, in yields determined by the relative concentrations of 4 and BrCCI3. Rate constants for coupling (k c) of Bu. and Ph. with 4 were assumed to be proportional to rate constants for diffusion controlled reactions, kd, which were estimated from measured viscosities. Values of k ! : and k; : , calculated from kc and product yields for reactions at 80°C, are 0.26 X lo9 and 1.55 X lo9 M-' s-l, respectively. The relative radical reactivities toward BrCC13 at 80°C are Ph, 6; cpm, 5; Bu, 1.

Research paper thumbnail of Thermolysis of α-hydroperoxyalkyl diazenes. Spin trapping of radical intermediates and spin trapping kinetics

Can J Chem, 1991

α-Hydroperoxyalkyl diazenes (Me2C(OOH)N=NR, 1, R = CH2CF3, CH2CH2OMe, CH(Me)2, CMe3, CH2Ph, Ph, C... more α-Hydroperoxyalkyl diazenes (Me2C(OOH)N=NR, 1, R = CH2CF3, CH2CH2OMe, CH(Me)2, CMe3, CH2Ph, Ph, CH2CH2OPh, and c-C3H5CD2) decompose in benzene, at 50 °C or less, by a mechanism involving free radical (R•) intermediates. The radicals were trapped with 1-methyl-4-nitroso-3,5-diphenylpyrazole, 2, to afford spin adducts (nitroxyls) that were observed by ESR spectroscopy. When the solvent was ethyl vinyl ether, radicals from 1 (R = CH2CH2OPh) were trapped by the solvent and the adduct radicals so formed were spin trapped by 2. These observations support free radical mechanisms for thermolysis of 1 and for the hydroxyalkylations that occur when 1 are decomposed in solutions containing enol ethers or other unsaturated substrates. The ring-opening of cyclopropylmethyl radicals (cpm) to 3-butenyl radicals was used to estimate the rate constant for radical trapping by 2. For cpm the rate constant is given by log kcpm = (10.7 ± 0.4) − (3.9 ± 0.5)/θ where θ = 2.3 RT kcal mol−1. At 25 °C, the spin trapping rate constant has the value 6.9 × 107 M−1 s−1. Key words: hydroperoxyalkyl diazenes; radicals, spin trapping; spin trapping, rate constant.

Research paper thumbnail of Rate constant for hydroxylation of a primary alkyl radical by induced decomposition of an alpha hydroperoxyalkyl diazene

Can J Chem, 1987

Rate constants for induced decomposition of 5-hexenyl(1-hydroperoxy-1-methylethyl) diazene ((CH3)... more Rate constants for induced decomposition of 5-hexenyl(1-hydroperoxy-1-methylethyl) diazene ((CH3)2C(OOH)N=N(CH2)4CH=CH2, 2) have been estimated. Thermolysis of 2 at 50 °C affords 5-hexenyl radicals which abstract the hydroxyl group from 2 in competition with cyclization of 5-hexenyl to cyclopentylmethyl radicals. The known rate constant (kc) for that cyclization was used to clock the bimolecular hydroxyl abstraction process. For reaction in hexafluorobenzene at 50 °C, the rate constant for abstraction of hydroxyl from 2 (kOH) was found to be dependent on the concentration of 2. For example, at [2] = 0.4 M, kOH = 3.2 × 106 M−1 s−1 whereas, at [2] = 0.10 M, kOH = 1.8 × 107 M−1 s−1. The concentration dependence of kOH is attributed to the effects of intermolecular hydrogen bonding and the large absolute values of kOH are ascribed to concerted induced decomposition, the O—O bond being broken in concert with scission of the nearest C—N bond of the azo function. The relevance of the results, to synthetic application of α-hydroperoxyalkyl diazenes in hydroxyalkylation reactions, is discussed.

Research paper thumbnail of The $ alpha$-hydroxyalkyl diazenes and the $ alpha$-hydroperoxyalkyl diazenes as sources of radicals for the kinetic studies of some radical-molecule reactions in solution

Research paper thumbnail of Rate constant for chlorine abstraction from CCl 4 by the 5-hexenyl radical

Can J Chem, 1987

Cyclization of the 5-hexenyl free radical to the cyclopentylmethyl free radical was used to clock... more Cyclization of the 5-hexenyl free radical to the cyclopentylmethyl free radical was used to clock chlorine atom abstraction by 5-hexenyl from carbon tetrachloride in solution. The source of 5-hexenyl radicals was 5-hexenyl[1-hydroxy-1-methyl-ethyl]diazene ((CH3)2C(OH)N=N(CH2)4CH=CH2), which decomposes thermally in CCl4 by a radical chain mechanism to afford chloroform, acetone, nitrogen, 6-chloro-1-hexene, cyclopentylchloromethane, 1-hexene, and methylcyclopentane as primary products. 6-Chloro-1-hexene is converted, in part, to a secondary product, 1,1,1,3,7-pentachloroheptane, by radical chain addition of CC14 to the double bond. The rate constant for chlorine atom abstraction, kCl, was calculated from the product composition and the known rate constant for cyclization of the 5-hexenyl radical. For the temperature range 274–353 K, kCl is given by log (kCl/M−1 s−1) = (8.4 ± 0.3) − (6.2 ± 0.4)/θ where θ = 2.3 RT kcal mol−1, which leads to [Formula: see text]. This value is significantly smaller than recently reported estimates for other primary alkyl radicals.

Research paper thumbnail of Thermolysis of α-hydroperoxyalkyl diazenes. Spin trapping of radical intermediates and spin trapping kinetics

Canadian Journal of Chemistry-revue Canadienne De Chimie, 1991

α-Hydroperoxyalkyl diazenes (Me2C(OOH)N=NR, 1, R = CH2CF3, CH2CH2OMe, CH(Me)2, CMe3, CH2Ph, Ph, C... more α-Hydroperoxyalkyl diazenes (Me2C(OOH)N=NR, 1, R = CH2CF3, CH2CH2OMe, CH(Me)2, CMe3, CH2Ph, Ph, CH2CH2OPh, and c-C3H5CD2) decompose in benzene, at 50 °C or less, by a mechanism involving free radical (R•) intermediates. The radicals were trapped with 1-methyl-4-nitroso-3,5-diphenylpyrazole, 2, to afford spin adducts (nitroxyls) that were observed by ESR spectroscopy. When the solvent was ethyl vinyl ether, radicals from 1 (R = CH2CH2OPh) were trapped by the solvent and the adduct radicals so formed were spin trapped by 2. These observations support free radical mechanisms for thermolysis of 1 and for the hydroxyalkylations that occur when 1 are decomposed in solutions containing enol ethers or other unsaturated substrates. The ring-opening of cyclopropylmethyl radicals (cpm) to 3-butenyl radicals was used to estimate the rate constant for radical trapping by 2. For cpm the rate constant is given by log kcpm = (10.7 ± 0.4) − (3.9 ± 0.5)/θ where θ = 2.3 RT kcal mol−1. At 25 °C, the spin trapping rate constant has the value 6.9 × 107 M−1 s−1. Key words: hydroperoxyalkyl diazenes; radicals, spin trapping; spin trapping, rate constant.

Research paper thumbnail of The Α-Hydroxyalkyl Diazenes and the Α-Hydroperoxyalkyl Diazenes as Sources of Radicals for the Kinetic Studies of Some Radical-Molecule Reactions in Solution

α-Hydroxyalkyl diazenes and -hydroperoxyallcyl diaz.enes are known for a long timeas initiators f... more α-Hydroxyalkyl diazenes and -hydroperoxyallcyl diaz.enes are known for a long timeas initiators for fn:e radical polymerization. Their application as suitable radical precursors for kinetic studies such as the radical-molecule and radical-radical reactions are not well-exploited. This thesis deals mainly with the rate constants for a number of radical-molecule reactions studied by generating radicals in solution from suitable radicalprecursors mentioned above. The initiation mechanism for the decomposition ofa-hydroxyalkyl diazenes was also investigated. Alkyl(1-hydroperoxy-1-methylethyl)diazenes (154) [(CH₃)₂C(OOH)N=NR] a, R = c-C₃H₅-CH₂; b,R = c-C₃H₅-CD₂; c, R = CH₂=CH-(CH₂)₃-CH₂; d, R =CH₃(CH₂)₂-CH₂ and phenyl(1-hydroperoxy-1-methylethyl)diazene (l54e) were prepared in solution by autoxidation of the corresponding hydrazones of acetone. They (154a-e) were converted to the corresponding alkyl(1-hydroxy-1-methylethyl)diazene (155a-d) andphenyl(1-hydroxy-1-methylethyl)diazene (155e)...

Research paper thumbnail of The Α-Hydroxyalkyl Diazenes and the Α-Hydroperoxyalkyl Diazenes as Sources of Radicals for the Kinetic Studies of Some Radical-Molecule Reactions in Solution

ABSTRACf a-Hydroxyalkyl diazenes and a-hydroperoxyallcyl diaz.enes are known for a long time as i... more ABSTRACf a-Hydroxyalkyl diazenes and a-hydroperoxyallcyl diaz.enes are known for a long time as initiators for fn:e radical polymerization. Their application as suitable radical precursors for kinetic studies such as the radical-molecule and radical-radical reactions are not well-exploited. This thesis deals mainly with the rate constants for a number of radical-molecule reactions studied by generating radicals in solution from suitable radical precursors mentioned above. The initiation mechanism for the decomposition of a-hydroxyalkyl diazenes was also investigated. Alkyl(l-hydroperoxy-l-methylethyl)diazenes (154) [(CH 3 hC(OOH)N=NR]:• a. R = c-~Hs-CH2; b, R = c-GJHs-CD:z; c, R = CH2=CH-(0I2~-CH2; d, R =CH 3 (CH 2 h-CH 2 and phenyl(l-hydroperoxy-l-methylethyl)diaz.ene (l54e) were prepared in solution by autoxidation of the corresponding hydrazones of acetone. They (l54a-e) were convened to the corresponding alkyl(l-hydroxy-l-methylethyl}diazene (155a-d) and phenyl(1-hydroxy-l-methylethyl}diazene (155e) by reduction with biphenyl phosphine. The radical chain decomposition of 5-hexenyl(1-hydroxy-I-methylethyl)diaz.ene (155c) in carbon tetrachloride and product analysis gave the rate constant for chlorine abstraction by the S-hexenyl radical. The rate constant was calculated from the product composition and the known rate constant for the cycli7ation of the S-hexenyl radical. For the tcmperature rangc 274-353 K, the rate constant is given by 10g(kdM•l s•l) = (8.4 ± 0.3)-(6.2 ± 0.4)/0, where 9 = 2.3 kcaVmol, which leads to ka¢C) =7.2 x 103 M•l s•l. Rearrangement of cyclopropylmethyl radical to the but-3-enyl radical was used to clock brominc and iodine abstraction reactions from a number of substrates. Cyclopropylmethyl(l-hydroxy-l-methylethyl}diazene (155a) was used as the source for yclopropylmcthylradical. Decomposition of lSSa in hexafluorobenzene or in dichloromethane containing bromotrichloromcthan~and product analysis enabled the calcv 1 .ation of the rate constant (leDr) for bromine abstraction by cyclopropylmcthyl radicals from bromottichloromcthanc.

Research paper thumbnail of Rate constants for abstraction of bromine from bromotrichloromethane by butyl, cyclopropylmethyl, and phenyl radicals in solution

Canadian Journal of Chemistry, 1988

The radical chain decomposition of cyclopropylmethyl (I-hydroxy-1-mcthylethy1)-diazcnc ((CH3)2C(O... more The radical chain decomposition of cyclopropylmethyl (I-hydroxy-1-mcthylethy1)-diazcnc ((CH3)2C(OH)N=NCHI-<1 1) at 253-341 K in hexafluorobenzene or in dichloromethane solution containing brornotrichloromethane affords cyclopropylmethyl bromide, 4-bromo-I-butene, I-bromo-5,5,5-trichloro-2-pentene, and 3,5-dibromo-I, I, I-trichloropcntane from the cyclopropylmethyl portion of 1. Other major products are nitrogen, acetone, and chloroform. The rate constant for formation of cyclopropylmethyl bromide by attack of cyclopropylmethyl free radicals from 1 at bromine of BrCCI, (kyy) was calculated from the product composition using the known rate constant for rearrangement of cyclopropylmethyl radicals to 3-buten-I-yl radicals. At 25"C, kTF = 6.5 X lo8 M-I s-I and the temperature dependence is given by log (ksm/M-I s-) = (10.6 5 0.3)-(2.4 C 0.4)/0, where 0 = 2.3R~kcal/mol-l. Non-chain decompositionof (CH3),C(OH)N=N-R(2, R = Bu, and3, R = Ph) in the presence of excess 1 ,I ,3,3-tetramethylisoindolin-2-yloxyl (4) and bromotrichloromethane afforded BuBr and PhBr, respectively, in yields determined by the relative concentrations of 4 and BrCCI3. Rate constants for coupling (k c) of Bu. and Ph. with 4 were assumed to be proportional to rate constants for diffusion controlled reactions, kd, which were estimated from measured viscosities. Values of k ! : and k; : , calculated from kc and product yields for reactions at 80°C, are 0.26 X lo9 and 1.55 X lo9 M-' s-l, respectively. The relative radical reactivities toward BrCC13 at 80°C are Ph, 6; cpm, 5; Bu, 1.

Research paper thumbnail of Thermolysis of α-hydroperoxyalkyl diazenes. Spin trapping of radical intermediates and spin trapping kinetics

Can J Chem, 1991

α-Hydroperoxyalkyl diazenes (Me2C(OOH)N=NR, 1, R = CH2CF3, CH2CH2OMe, CH(Me)2, CMe3, CH2Ph, Ph, C... more α-Hydroperoxyalkyl diazenes (Me2C(OOH)N=NR, 1, R = CH2CF3, CH2CH2OMe, CH(Me)2, CMe3, CH2Ph, Ph, CH2CH2OPh, and c-C3H5CD2) decompose in benzene, at 50 °C or less, by a mechanism involving free radical (R•) intermediates. The radicals were trapped with 1-methyl-4-nitroso-3,5-diphenylpyrazole, 2, to afford spin adducts (nitroxyls) that were observed by ESR spectroscopy. When the solvent was ethyl vinyl ether, radicals from 1 (R = CH2CH2OPh) were trapped by the solvent and the adduct radicals so formed were spin trapped by 2. These observations support free radical mechanisms for thermolysis of 1 and for the hydroxyalkylations that occur when 1 are decomposed in solutions containing enol ethers or other unsaturated substrates. The ring-opening of cyclopropylmethyl radicals (cpm) to 3-butenyl radicals was used to estimate the rate constant for radical trapping by 2. For cpm the rate constant is given by log kcpm = (10.7 ± 0.4) − (3.9 ± 0.5)/θ where θ = 2.3 RT kcal mol−1. At 25 °C, the spin trapping rate constant has the value 6.9 × 107 M−1 s−1. Key words: hydroperoxyalkyl diazenes; radicals, spin trapping; spin trapping, rate constant.

Research paper thumbnail of Rate constant for hydroxylation of a primary alkyl radical by induced decomposition of an alpha hydroperoxyalkyl diazene

Can J Chem, 1987

Rate constants for induced decomposition of 5-hexenyl(1-hydroperoxy-1-methylethyl) diazene ((CH3)... more Rate constants for induced decomposition of 5-hexenyl(1-hydroperoxy-1-methylethyl) diazene ((CH3)2C(OOH)N=N(CH2)4CH=CH2, 2) have been estimated. Thermolysis of 2 at 50 °C affords 5-hexenyl radicals which abstract the hydroxyl group from 2 in competition with cyclization of 5-hexenyl to cyclopentylmethyl radicals. The known rate constant (kc) for that cyclization was used to clock the bimolecular hydroxyl abstraction process. For reaction in hexafluorobenzene at 50 °C, the rate constant for abstraction of hydroxyl from 2 (kOH) was found to be dependent on the concentration of 2. For example, at [2] = 0.4 M, kOH = 3.2 × 106 M−1 s−1 whereas, at [2] = 0.10 M, kOH = 1.8 × 107 M−1 s−1. The concentration dependence of kOH is attributed to the effects of intermolecular hydrogen bonding and the large absolute values of kOH are ascribed to concerted induced decomposition, the O—O bond being broken in concert with scission of the nearest C—N bond of the azo function. The relevance of the results, to synthetic application of α-hydroperoxyalkyl diazenes in hydroxyalkylation reactions, is discussed.

Research paper thumbnail of The $ alpha$-hydroxyalkyl diazenes and the $ alpha$-hydroperoxyalkyl diazenes as sources of radicals for the kinetic studies of some radical-molecule reactions in solution

Research paper thumbnail of Rate constant for chlorine abstraction from CCl 4 by the 5-hexenyl radical

Can J Chem, 1987

Cyclization of the 5-hexenyl free radical to the cyclopentylmethyl free radical was used to clock... more Cyclization of the 5-hexenyl free radical to the cyclopentylmethyl free radical was used to clock chlorine atom abstraction by 5-hexenyl from carbon tetrachloride in solution. The source of 5-hexenyl radicals was 5-hexenyl[1-hydroxy-1-methyl-ethyl]diazene ((CH3)2C(OH)N=N(CH2)4CH=CH2), which decomposes thermally in CCl4 by a radical chain mechanism to afford chloroform, acetone, nitrogen, 6-chloro-1-hexene, cyclopentylchloromethane, 1-hexene, and methylcyclopentane as primary products. 6-Chloro-1-hexene is converted, in part, to a secondary product, 1,1,1,3,7-pentachloroheptane, by radical chain addition of CC14 to the double bond. The rate constant for chlorine atom abstraction, kCl, was calculated from the product composition and the known rate constant for cyclization of the 5-hexenyl radical. For the temperature range 274–353 K, kCl is given by log (kCl/M−1 s−1) = (8.4 ± 0.3) − (6.2 ± 0.4)/θ where θ = 2.3 RT kcal mol−1, which leads to [Formula: see text]. This value is significantly smaller than recently reported estimates for other primary alkyl radicals.

Research paper thumbnail of Thermolysis of α-hydroperoxyalkyl diazenes. Spin trapping of radical intermediates and spin trapping kinetics

Canadian Journal of Chemistry-revue Canadienne De Chimie, 1991

α-Hydroperoxyalkyl diazenes (Me2C(OOH)N=NR, 1, R = CH2CF3, CH2CH2OMe, CH(Me)2, CMe3, CH2Ph, Ph, C... more α-Hydroperoxyalkyl diazenes (Me2C(OOH)N=NR, 1, R = CH2CF3, CH2CH2OMe, CH(Me)2, CMe3, CH2Ph, Ph, CH2CH2OPh, and c-C3H5CD2) decompose in benzene, at 50 °C or less, by a mechanism involving free radical (R•) intermediates. The radicals were trapped with 1-methyl-4-nitroso-3,5-diphenylpyrazole, 2, to afford spin adducts (nitroxyls) that were observed by ESR spectroscopy. When the solvent was ethyl vinyl ether, radicals from 1 (R = CH2CH2OPh) were trapped by the solvent and the adduct radicals so formed were spin trapped by 2. These observations support free radical mechanisms for thermolysis of 1 and for the hydroxyalkylations that occur when 1 are decomposed in solutions containing enol ethers or other unsaturated substrates. The ring-opening of cyclopropylmethyl radicals (cpm) to 3-butenyl radicals was used to estimate the rate constant for radical trapping by 2. For cpm the rate constant is given by log kcpm = (10.7 ± 0.4) − (3.9 ± 0.5)/θ where θ = 2.3 RT kcal mol−1. At 25 °C, the spin trapping rate constant has the value 6.9 × 107 M−1 s−1. Key words: hydroperoxyalkyl diazenes; radicals, spin trapping; spin trapping, rate constant.

Research paper thumbnail of The Α-Hydroxyalkyl Diazenes and the Α-Hydroperoxyalkyl Diazenes as Sources of Radicals for the Kinetic Studies of Some Radical-Molecule Reactions in Solution

α-Hydroxyalkyl diazenes and -hydroperoxyallcyl diaz.enes are known for a long timeas initiators f... more α-Hydroxyalkyl diazenes and -hydroperoxyallcyl diaz.enes are known for a long timeas initiators for fn:e radical polymerization. Their application as suitable radical precursors for kinetic studies such as the radical-molecule and radical-radical reactions are not well-exploited. This thesis deals mainly with the rate constants for a number of radical-molecule reactions studied by generating radicals in solution from suitable radicalprecursors mentioned above. The initiation mechanism for the decomposition ofa-hydroxyalkyl diazenes was also investigated. Alkyl(1-hydroperoxy-1-methylethyl)diazenes (154) [(CH₃)₂C(OOH)N=NR] a, R = c-C₃H₅-CH₂; b,R = c-C₃H₅-CD₂; c, R = CH₂=CH-(CH₂)₃-CH₂; d, R =CH₃(CH₂)₂-CH₂ and phenyl(1-hydroperoxy-1-methylethyl)diazene (l54e) were prepared in solution by autoxidation of the corresponding hydrazones of acetone. They (154a-e) were converted to the corresponding alkyl(1-hydroxy-1-methylethyl)diazene (155a-d) andphenyl(1-hydroxy-1-methylethyl)diazene (155e)...