Überführung von l(−)‐Asparagin in l(−)‐Serin

Schneider, Ferdinand

doi:10.1002/jlac.19375290102

Cited by 26 publications

(8 citation statements)

References 20 publications

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“…The -secoestrone (2a), easily accessible in four steps from 3-methoxyestrone (1a) through a Grob fragmentation Scheme 1. Reaction of the secoestrone aldehyde 2a derived from 3-methoxyestrone (1a) and p-bromoaniline in the presence of BF 3 ·OEt 2 as a key step, [30] was hydrogenated to give the saturated aldehyde 6a (Scheme 2). Treatment of 6a with aniline (7) or with its mono-, di-and trisubstituted derivatives 8Ϫ28, containing electron-withdrawing halo, nitro or halomethyl groups in different positions, produced the imines 29Ϫ50, which readily underwent transformation in the presence of BF 3 ·OEt 2 .…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Novel D‐Secoestrone Isoquinuclidines by an Unpredicted Iminium Ion‐Induced 1,5‐Hydride Shift

et al. 2003

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Unique 9,13-bridged D-secoestrone alkaloids have been synthesized and structurally characterized. Treatment of 3-methoxy-16,17-secoestra-1,3,5(10)-trien-17-al (6a) with aniline (7) or substituted aniline derivatives 8−28 in the presence of different Lewis and Brønsted acids produces the bridged azaestrone derivatives 51−67 and the alkenes 68−73 in high yields in a domino-type process. The imines 29−50 are proposed as intermediates, undergoing 1,5-hydride shifts via the

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Section: Resultsmentioning

confidence: 99%

Synthesis of Novel D‐Secoestrone Isoquinuclidines by an Unpredicted Iminium Ion‐Induced 1,5‐Hydride Shift

et al. 2003

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“…This can be achieved by the formylation of 17-ketosteroids at C-16. 33 16-Formyl-17-ketosteroids (35) can be transformed into D-secosteroids (36), by including a Grob fragmentation as the key step (Scheme 8). 34,35 These fragmentation products (39) bear two valuable functional groups, a formyl and an allyl group, which allow a wide range of further transformations.…”

Section: Fragmentation -Cyclization Strategiesmentioning

confidence: 99%

“…33 16-Formyl-17-ketosteroids (35) can be transformed into D-secosteroids (36), by including a Grob fragmentation as the key step (Scheme 8). 34,35 These fragmentation products (39) bear two valuable functional groups, a formyl and an allyl group, which allow a wide range of further transformations. An effective, simple epimerization of C-13 has been elaborated for the synthesis of 17-keto-13α-5-androstenes 36 and -estranes.…”

Section: Fragmentation -Cyclization Strategiesmentioning

confidence: 99%

Recent developments in the isolation and synthesis of D-homosteroids and related compounds

Wölfling

2007

Arkivoc

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Both naturally occurring and synthetic D-homologs of compounds with a sterane skeleton exhibit diverse biological activity. The main sources of isolation are plants and marine organisms. The synthetic D-homosteroids are potential leads for drug discovery. This review focuses on steroids with a six-membered carbocyclic ring D and related compounds, the isolation or syntheses of which were reported between the mid-1990s and mid-2006.

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confidence: 99%

“…The yellow oil obtained by evaporation of the hydrolysate was treated with nitrous acid (Schneider, 1937) to convert any free amine present to a diazonium salt. The diazonium salt was hydrolyzed by stirring at 30°, pH 3, for about 1 hr (Schneider, 1937). Evaporation of an ethyl acetate extract of the acidic reaction mixture yielded a yellow oil which could be separated into two products by thin-layer chromatography (see Table I).…”

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confidence: 99%

Specificity of the neurotoxin from Lathyrus sativus as an amino acid antagonist

Mehta¹,

Hsu²,

Haskell³

1972

Biochemistry

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This paper reports evidence that a neurotoxin from the pulse Lathyrus sativus behaves as a potent amino acid antagonist in certain microorganisms. The toxin was isolated in 1963 from Lathyrus sativus seeds. Consumption of these seeds as a major calorie source has long been associated with outbreaks of the paralytic human disease known as neurolathyrism. The toxin was assigned the structure ß-oxalyl-L-a,/3-diaminopropionic acid. This paper describes work to confirm the structure of the toxin and to determine its specificity as an amino acid antagonist. The toxin depresses c X^Vonsumption of Lathyrus peas has been associated for more than 2000 years with a crippling human disease now known as neurolathyrism. (For recent reviews, see Padmanaban, 1969, andRao et al., 1969.) Three research groups in India (Murti et al., 1964;Roy et al., 1963;Rao et al., 1964) have reported the isolation of a neurotoxin from Lathyrus sativus seeds. The toxin produces muscle tremors, paralysis of the legs, and convulsions when injected into animals with an immature or damaged blood-brain barrier (Rao and Sarma, 1967) or when introduced intrathecally into adult monkeys . The toxin was assigned the structure /3-7V-oxaIyl-L-a,/3-diaminopropionic acid (Rao et al., 1964;Murti et al., 1964), and its possible role as the cause of human neurolathyrism was suggested.Conclusive evidence that human neurolathyrism is due solely to /3-A-oxalyl-L-a,0-diaminopropionic acid is lacking. However, the compound warrants investigation because of its demonstrated neurotoxic properties.The structural similarity of the toxin to common amino acids suggested to us that its neurotoxicity may stem from a possible role as an amino acid antagonist. This paper describes work to confirm the structure of the toxin and to determine the specificity of the toxin as an amino acid antagonist. Materials and MethodsSynthetic Toxin. All microbiological experiments described in this paper were carried out with highly purified synthetic toxin prepared from the copper chelate of L-a,/3-diaminopropionic acid and ethyl oxalyl chloride. L-a,/3-Diaminopropionic acid (Calbiochem, La Jolla, Calif.) was converted to a copper chelate as described by Rao et al., 1964. Ethyl oxalyl chloride was synthesized in about 85% yield with f From the

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Überführung von l(−)‐Asparagin in l(−)‐Serin

Cited by 26 publications

References 20 publications

Synthesis of Novel D‐Secoestrone Isoquinuclidines by an Unpredicted Iminium Ion‐Induced 1,5‐Hydride Shift

Synthesis of Novel D‐Secoestrone Isoquinuclidines by an Unpredicted Iminium Ion‐Induced 1,5‐Hydride Shift

Recent developments in the isolation and synthesis of D-homosteroids and related compounds

Specificity of the neurotoxin from Lathyrus sativus as an amino acid antagonist

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