Directional effects of substituents in the ozonolysis of nephthalenes. Synthesis of o-phthalaldehydes

Pappas, James J.; Keaveney, William P.; Berger, Melvin G.; Rush, Raymond V.

doi:10.1021/jo01266a063

Cited by 21 publications

(5 citation statements)

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“…A solution of N ε -acryloyl- l -lysine (vide supra, 0.2 g) in CH 3 OH was treated with a stream of O 3 for 45 min at −78 °C. The reaction was purged with Ar for 5 min to remove dissolved O 3 and 5 mL of (CH 3 ) 2 S was added, and the reaction mixture was stirred at −78 °C for 2 h and then at room temperature for 12 h. , The reaction mixture was taken to dryness in vacuo and the product was purified by recrystallization from EtOH (yield 30%): 1 H NMR (D 2 O) δ 1.45 (m, 2H, γ -C H 2 ), 1.68 (m, 2H, β -C H 2 ), 1.87 (m, 2H, δ -C H 2 ), 2.98 (t, 2H, ε -C H 2 ), 3.76 (t, 2H, α -C H ), 5.12 (s, 1H, COC H O); 13 C NMR (D 2 O) 22.0 ppm ( γ - C H 2 ), 26.6 ( δ - C H 2 ), 30.5 ( β - C H 2 ), 53.9 ( ε - C H 2 ), 55.3 ( α - C H), 169.0 (CO C HO), 174.7 ( C OCHO), 175.7 ( C OOH); MS, m / z 203.22 (MH + ).…”

Section: Methodsmentioning

confidence: 99%

Mechanism of Aqueous Decomposition of Trichloroethylene Oxide

and

Guengerich

1999

J. Am. Chem. Soc.

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The aqueous decomposition of trichloroethylene (TCE) oxide is shown to involve both pH-independent and hydronium ion-dependent regions. C−C bond scission is a major reaction at all pH values. Disappearance of TCE oxide is the rate-determining step for the formation of CO under the conditions studied. The product distribution of CO and three carboxylic acids (HCO2H, Cl2CHCO2H, and glyoxylic acid) did not change considerably over the pH range of −1.5−14, in general, even though the hydrolysis mechanism changes from hydronium ion-dependent to pH-independent. Mechanisms for the hydronium ion-dependent and pH-independent hydrolysis of TCE oxide were elucidated on the basis of the results of H2 18O and H incorporation and identification of products of the reaction of TCE oxide with lysine in both H2 16O and H2 18O. In the pH-independent hydrolysis, a zwitterionic intermediate could be formed and undergo an intramolecular rearrangement (Cl- shift) to generate dichloroacetyl chloride, which would subsequently decompose to Cl2CHCO2H. The zwitterionic intermediate could also hydrolyze at the less sterically hindered methylene to give a glycol anion, which would dehydrohalogenate to form an oxoacetyl chloride intermediate. The oxoacetyl chloride could hydrolyze to generate either glyoxylic acid, as a final product, or an anionic intermediate, which could go through a concerted mechanism to generate CO, HCO2H, and chloride. A mechanism proposed for the hydronium ion-dependent hydrolysis is very similar to that for the pH-independent hydrolysis except for the first step, which involves hydronium ion attack on TCE oxide to form a TCE-oxide cation intermediate. The lysine amide adducts were characterized by HPLC and mass spectrometry as those resulting from reaction with the postulated acyl chlorides.

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Section: Methodsmentioning

confidence: 99%

Mechanism of Aqueous Decomposition of Trichloroethylene Oxide

and

Guengerich

1999

J. Am. Chem. Soc.

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“…This rearrangement shares with the Beckmann rearrangement the feature that the migrating group retains its stereochemical configuration. The migration is usually considered to be concerted 79 Chern. Soc.…”

Section: Migration To Nitrogenmentioning

confidence: 99%

Advanced Organic Chemistry

Carey

Sundberg

1995

126

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“…An unsuccessful attempt was made to avoid the dimethyl sulfoxide difficu1ty.b~ steam distillation prior to extraction. It is possible that this problem using dimethyl sulfide in the preparation of o-phthalaldehyde was encountered by Pappas et al (12) 3Microanalyses were carried out using a Perkin-Elmer 240 Elemental Analyser. 4All n.m.r.…”

Section: Methodsmentioning

confidence: 99%

“…Pappas and co-workers (1 1, 12) confirmed the surprising resistance of the cyclic hydroxymethoxyperoxide intermediate to reduction by sodium iodide. He was successful in obtaining a 40-50% yield of o-phthalaldehyde (as the bis [(2,4-dinitropheny1)-hydrazone] derivative) by treating the cold methanolic ozonation product with dimethyl sulfide (1 1) and a 57% yield using triphenylphosphine (12).…”

mentioning

confidence: 99%