5385-87-5Relevant academic research and scientific papers
The p: K a of Br?nsted acids controls their reactivity with diazo compounds
Fei, Na,Sauter, Basilius,Gillingham, Dennis
, p. 7501 - 7504 (2016/06/14)
We study the O-alkylation of phosphate groups by alkyl diazo compounds in a range of small molecules and biopolymers. We show that the relatively high pKa of phosphate in comparison to the other naturally occurring Br?nsted acids can be exploited to control alkylation selectivity. We provide a simple protocol for chemical modification of some of the most important instances of phosphates in natural compounds including in small molecule metabolites, nucleic acids, and peptides.
Syntheses of Phospholipids Containing 2-Nitrobenzyl Ester Moieties at the Terminals of Alkyl Chains and Properties of Photodegradable Liposomes from the Lipids
Yamaguchi, Kazuo,Tsuda, Yoshihiro,Shimakage, Taka-Aki,Kusumi, Akihiro
, p. 1923 - 1929 (2007/10/03)
Phospholipid 1a bearing 2-nitrobenzyl ester moieties as a photocleavable group at the terminal of alkyl chains was synthesized from the corresponding terminal carboxy-bearing phospholipid 2 by the reaction with 2-nitrophenyl-substituted diazomethane. Phospholipid, 1b bearing α-methyl-2-nitrobenzyl group, 1c bearing 4,5-dimethoxy-2-nitrobenzyl group, and 1d bearing α-methyl-4,5-dimethoxy-2-nitrobenzyl group were similarly synthesized by the use of the respective diazo compounds. The order of photolysis rates of 2-nitrobenzyl ester linkage of phospholipids by ultrahigh-pressure mercury lamp is 1b≥1d > 1a > 1c. Liposomes of 1a-1d containing calcein in the inner aqueous layer were prepared by vortexing, sonication, and gel-filtration. UV irradiation resulted in fast release of the entrapped fluorescence dye. The order of release rates : 1b≥1d > 1c> 1a is consistent with that of photolysis rates except for 1c, which has poor retention of the dye.
Photochemistry of (2-nitrophenyl)diazomethane studied by the matrix isolation technique. (Nitrophenyl)carbene to (carboxylphenyl)nitrene rearrangement by successive reduction of the nitro group with the carbenic center
Tomioka, Hideo,Ichikawa, Naoki,Komatsu, Kazunori
, p. 8045 - 8053 (2007/10/02)
Irradiation (λ > 350 nm) of (2-nitrophenyl)diazomethane (1) matrix-isolated in Ar at 10 K provided 2-nitrosobenzaldehyde (3) presumably as a result of intramolecular oxygen migration in (2-nitrophenyl)carbene (2). Upon further irradiation (λ > 350 nm), 3 was decomposed to give a mixture of 2,1-benzisoxazol-3(1H)-one (4) and carbonylcyclopentadiene imine (5) along with CO2. The oxazolone (4) underwent decarboxylation to give 5 upon irradiation with shorter wavelength light (λ > 300 nm) but not at longer wavelength (λ > 350 nm), suggesting 4 is not the direct precursor for 5 in the photolysis of 3. Irradiation (λ > 350 nm) of (4-n-butyl-2-nitrophenyl)diazomethane (1b) under similar conditions resulted in the formation of carbonyloximinocyclohexadienylidene (7) which then produced the oxazolone (4b) and the imine (5b) upon further irradiation, suggesting that a 1,4-biradical generated as a result of abstraction of H at the ortho position by the photoexcited nitroso group was involved in the reaction of 3 forming 4. (2-Carboxyphenyl)nitrene (9) generated by 1,4-OH shift in the 1,4-biradical was postulated as an intermediate leading to 5, and this was actually demonstrated by independent generation of 9 by the photolysis of 2-azidobenzoic acid (8).
A Discriminating Protecting Group Strategy for Alcohols and Amines
Liotta, Louis J.,Ganem, Bruce
, p. 215 - 222 (2007/10/02)
The protection of alcohols and amines as O- and N-benzyl derivatives has long played a central role in organic synthesis.For case where the conventional method of benzylation under strongly base conditions is not applicable, we now describe an alternate method using phenyldiazomethane that proceeds under near-neutral conditions with HBF4 as a catalyst.O-Benzylation occurs at -40 deg C and works well on primary, secondary, and tertiary alcohols.The techique is compatible with ester, acetal, and relative halide functiolatities.Under the same conditions PhCHN2 also N-benzylates primary and secondary amines, albait more slowly.However S-benzylation is only marginally successful.As a consequence aminoalcohols like 2-hydroxymethylpiperidine can be O-benzylayed cleanly and in good yield.Thus HBF4-mediated benzylations using PhCHN2 achieve a kinetic selectivity not customarily possible in the standard Williamson ether synthesis.Preliminary experiments with other, substituted phenyldiazomethanes indicate the method can be extended to the production of substituted benzyl ethers and amines.
