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PubMedDate not supplied

[Preliminary study of the comparative action of 1 methyl-2 (2 naphtyl) aziridine on kindling effect and on paradoxical sleep (author's transl)].

Methyl-2 (2 Naphtyl) Aziridine (MNA) is a new agent which has been demonstrated to have effects on paradoxical sleep (PS) and on the levels of cerebral noradrenaline (Yamamoto, 1975). It has been tried on a experimental model of epilepsy, the kindling effect, produced in the cat by repetitive stimulation of the amygdala. The results obtained in the cat confirmed blockage of paradoxical sleep (PS) and revealed a marked reduction in the number of stimuli required to produce the effect. The shortening of the time before the first generalised seizure did not seem attributable to privation of paradoxical sleep. The role of cerebral catecholamine reduction, however, is discussed.

Animals↗
PubMed2001

Searches for new interstellar molecules, including a tentative detection of aziridine and a possible detection of propenal.

Rotational spectroscopy at millimeter wavelengths is a powerful means of investigating the chemistry of dense interstellar clouds. These regions can exhibit an interesting complement of gas phase molecules, including relatively complex organics. Here we report the tentative first astronomical detection of aziridine (ethylenimine), the possible detection of propenal (acrolein), and upper limits on the abundances of cyclopropenone, furan, hydroxyethanal (glycolaldehyde), thiohydroxylamine (NH2SH), and ethenol (vinyl alcohol) in various interstellar clouds.

Acetaldehyde↗
PubMed2005

Chemistry of tetrathiomolybdate: aziridine ring opening reactions and facile synthesis of interesting sulfur heterocycles.

Benzyltriethylammonium tetrathiomolybdate, [BnEt3N]2MoS4, has been used successfully to effect ring opening of aziridines in a regiospecific and stereospecific manner under mild reaction conditions without the use of Lewis acid catalyst. Utility of this reagent in tandem and multistep processes in a one-pot operation for the synthesis of various novel sulfur heterocycles in very good yield is also reported.

Aziridines↗
PubMed2006

De novo synthesis of Tamiflu via a catalytic asymmetric ring-opening of meso-aziridines with TMSN3.

An asymmetric ring-opening reaction of meso-aziridines with TMSN3 was developed using a catalyst prepared from Y(OiPr)3 and chiral ligand 2 in a 1:2 ratio. Excellent enantioselectivity was realized from a wide range of substrates with a practical catalyst loading. The products were efficiently converted to enantiomerically enriched 1,2-diamines, which are versatile chiral building blocks for pharmaceuticals and chiral ligands. This reaction was applied to a catalytic asymmetric synthesis of Tamiflu, a very important anti-influenza drug containing a chiral 1,2-diamino functionality.

Antiviral Agents↗
PubMed1991

Dual-function radiosensitizers. Alpha-[[(2-bromoethyl)amino]methyl]-2-nitro-1H-imidazole-1-ethanol and related compounds: preparation via an aziridine equivalent.

An improved synthesis of the dual-function radiosensitizer alpha-[[(2-bromoethyl)amino]methyl]-2-nitro-1H-imidazole-1-ethanol (2, RB 6145) has been developed. Previously, the synthetic difficulties associated with this compound limited its attractiveness as a clinical candidate, although its radiosensitizing activity in preclinical models warranted its further development. The synthesis described uses a 2-oxazolidinone as an aziridine equivalent and provides 2 in 47% yield.

Acetates↗
PubMed1986

Isolation, synthesis, and antitumor evaluation of spirohydantoin aziridine, a mutagenic metabolite of spirohydantoin mustard.

Spirohydantoin mustard (SHM), a central nervous system directed nitrogen mustard with anticancer activity, was metabolized in the presence of mouse liver postmitochondrial supernatant (9000g fraction) to a nonpolar alkylating metabolite. The metabolite was isolated by thin-layer chromatography of chloroform or ethyl acetate extracts of incubation mixtures, and its structure was established by mass spectral analysis, synthesis, and cochromatography. The metabolite, spirohydantoin aziridine, was mutagenic for Salmonella typhimurium TA1535 in the Ames assay but inactive as an antitumor agent against P388 leukemia in vivo.

Animals↗
PubMed1990

2-(4-Amino-4-carboxybutyl)aziridine-2-carboxylic acid. A potent irreversible inhibitor of diaminopimelic acid epimerase. Spontaneous formation from alpha-(halomethyl)diaminopimelic acids.

2-(4-Amino-4-carboxybutyl)aziridine-2-carboxylic acid (3) (aziridino-DAP) was identified as the product of spontaneous hydrolysis of alpha-(halomethyl)diaminopimelic acids (alpha-halomethyl-DAPs) 2a-c. Under physiological conditions, 3 is an extremely potent irreversible inhibitor of the bacterial enzyme diaminopimelic acid epimerase (DAP-epimerase; EC 5.1.1.7). This unusual mode of action of an alpha-halomethyl amino acid with a non-pyridoxal enzyme is investigated. Synthesis and characterization of 2a-c and 3, kinetics of spontaneous formation of 3 from alpha-halomethyl-DAPs, and kinetics of enzyme inhibition by both 3 and by alpha-halomethyl-DAPs are reported.

Amino Acid Isomerases↗
PubMed1999

Crystal structure of human DT-diaphorase: a model for interaction with the cytotoxic prodrug 5-(aziridin-1-yl)-2,4-dinitrobenzamide (CB1954).

The crystal structure of human DT-diaphorase (NAD(P)H oxidoreductase (quinone); EC 1.6.99.2) has been determined to 2.3 A resolution. There are only minor differences in shape and volume between the active sites of the rat and human enzymes and in the hydrophobic environment in the vicinity of the substrate. The isoalloxazine ring of the bound FAD is more buried in the human structure. Molecular modeling was used to examine optimal positions for the antitumor prodrug CB1954 (5-(aziridin-1-yl)-2,4-dinitrobenzamide) in both the human and rat enzyme active sites. This suggests that the position of CB1954 in the active site of the human enzyme is very similar to that in the rat, although there are detailed differences in the predicted patterns of hydrogen bonding between side chains and the drug. Some of the differences are a consequence of the shift in position for the FAD molecule and may contribute to the observed differences in rate of the two-electron reduction of CB1954.

Amino Acid Sequence↗
PubMed2002

Regioselective and stereoselective nucleophilic ring opening reactions of a phenyl-substituted aziridine: enantioselective synthesis of beta-substituted tryptophan, cysteine, and serine derivatives.

The asymmetric synthesis of beta-phenyl-substituted cysteine, tryptophan, and serine derivatives was successfully developed. In this approach, the key intermediate, enantiomerically pure 3-phenylaziridine-2-carboxylic ester 7, was prepared from alpha,beta-unsaturated ester 1 by employing the Sharpless asymmetric dihydroxylation. The aziridine 7 was treated with 4-methoxybenzylthiol, indole, and acetic acid to give beta-phenyl-substituted cysteine, tryptophan, and serine, respectively, in a clean S(N)2 type ring opening at the C3 position. This general approach can be used to synthesize a variety of beta-substituted novel amino acids.

Amino Acids↗
PubMed2003

Regio- and stereoselectivity of diethylaluminum azide opening of trisubstituted epoxides and conversion of the 3 degrees azidohydrin adducts to isoprenoid aziridines.

The regioisomer ratios (3 degrees,2 degrees /2 degrees,3 degrees ), and in some cases the stereochemistry, of vicinal azidohydrins formed in reactions of 11 trisubstituted terpene epoxides with Et(2)AlN(3) in toluene are reported. The more highly substituted azide usually predominated (3 degrees,2 degrees /2 degrees,3 degrees ratios >or= 40:1 to 2.5-1) in accord with a Markovnikov orientation and an S(N)1-like transition state. Reversed regioisomer ratios were observed with 6,7-epoxygeranyl acetate (1:2.5) and cis-1,2-epoxylimonene (1:3.3 to 1:10). The tertiary azido diols from 2,3-epoxygeraniol, 2,3-epoxyfarnesol, and 2,3-epoxynerol were formed as single isomers with inversion of configuration at C3 (>or= 35-40:1 for the C(10) azido diols). The regioselectivity was affected by the presence and proximity of oxy functional groups on the epoxide substrate (OH, OAc, and OSi-tBuMe(2)), the equivalents of Et(2)AlN(3), and additives (EtOAc or EtOH). The results and trends are rationalized by consideration of the structural and stereoelectronic characteristics of proposed diethylaluminum epoxonium ion intermediates and transition states, together with the nucleophilicity of the azide donor. Six of the 3 degrees,2 degrees azidohydrins were converted to the corresponding aziridines by primary-selective silylations of four azido diols, mesylations, and reductive cyclizations with LiAlH(4).

Azides↗
PubMed2003

Improved asymmetric synthesis of aziridine 2-phosphonates using (S)-(+)-2,4,6-trimethylphenylsulfinamide.

The aza-Darzens reaction of lithium diethyl iodomethylphosphonate with enantiopure N-(2,4,6-trimethylphenylsulfinyl)imines affords a single diastereomeric N-sulfinylaziridine 2-phosphonate which, on treatment with MeMgBr, gives the corresponding NH-aziridine 2-phosphonate chiral building blocks. An improved asymmetric synthesis of (S)-(+)-2,4,6-trimethylphenylsulfinamide is also given.

Aziridines↗
PubMed2005

o-nitrobenzenesulfonamides in nucleoside synthesis: efficient 5'-aziridination of adenosine.

5'-Aziridinoadenylates of the form 1 and a related nitrogen mustard variant have been constructed using a novel variation of the Mitsunobu reaction. Such molecules allow conversion of biological methyltransferases into nucleoside transferases, thus providing powerful tools for investigating S-adenosyl-l-methionine (SAM)-dependent methylation. We present here a highly effective synthesis of such molecules that is amenable to aziridine diversification as well as elaboration of the base moiety so as to afford "bumped" cofactor mimics compatible with "hole"-bearing mutant proteins.

Adenosine↗
PubMed2006

Mechanism and diastereoselectivity of aziridine formation from sulfur ylides and imines: a computational study.

A computational investigation of the title reaction involving semistabilized (R = Ph) and stabilized (R = CO2Me) sulfur ylides has been performed using DFT methods including a continuum model of solvent. Our results provide support for the generally accepted mechanism and are in very good agreement with observed cis/trans selectivities. This study shows that betaine formation is nonreversible, and that selectivity is thereby determined at the initial addition step, in the case of semistabilized ylides. Our analysis indicates moreover that addition TS structures are governed by the steric strain induced by the N-sulfonyl group, which favors the transoid approach in the case of syn betaine formation and the cisoid mode of addition in anti TSs. The observed low trans selectivity is accounted for by the favorable Coulombic interactions and stabilization by C-H...O hydrogen bonding allowed in the cisoid anti addition TS. In the case of stabilized ylides, the endothermicity of betaine formation combined with the high barrier to ring closure render the elimination step rate- and selectivity-determining. Accordingly, the low cis selectivity observed in stabilized ylide reactions is explained by the lower steric strain in the elimination step generated by the formation of the cis aziridine (as compared to the trans case).

Aziridines↗
PubMed2006

A theoretical study of rhodium(I) catalyzed carbonylative ring expansion of aziridines to beta-lactams: crucial activation of the breaking C-N bond by hyperconjugation.

The regioselectivity and enantiospecificity of the [Rh(CO)2Cl]2-catalyzed carbonylative ring expansions of N-tert-butyl-2-phenylaziridine to yield 2-azetidinone and the lack of reactivity of N-tert-butyl-2-methylaziridine along this process were investigated at the B3LYP/6-31G(d) (LANL2DZ for Rh) theory level taking into account solvent effects. According to our results, the regioselectivity in the ring expansion of N-tert-butyl-2-phenylaziridine and the unreactivity of N-tert-butyl-2-methylaziridine experimentally observed are determined by the different degree of activation of the breaking C-N bond in the initial aziridine-Rh(CO)2Cl complex due to its hyperconjugation interaction with the substituent on the carbon atom. When a phenyl substituent is present its hyperconjugation interaction with the C(alpha)-N bond facilitates the insertion of the metal atom into this bond. On the other hand, when the substituent is a methyl group, a larger stability of the initial complex along with a lower stabilization through hyperconjugation of the TS for insertion of the Rh atom into the C(alpha)-N bond make the ring expansion of N-tert-butyl-2-methylaziridine unviable. The enantiospecificity experimentally observed is also reproduced by our calculations given that the stereogenic center is never perturbed to change its configuration.

Aziridines↗
PubMed2001

An efficient synthesis of (-)-chloramphenicol via asymmetric catalytic aziridination: a comparison of catalysts prepared from triphenylborate and various linear and vaulted biaryls.

[reaction--see text] The antibiotic (-)-choramphenicol has been synthesized in only four steps from p-nitro-benzaldehyde in optically pure form from an asymmetric catalytic aziridination reaction with a chiral catalyst prepared from triphenylborate and the (R)-VAPOL ligand. Catalysts generated from the VAPOL and VANOL ligands give much higher asymmetric induction than do catalysts prepared from 6,6'-diphenylVAPOL, BINOL, and BANOL ligands.

Anti-Bacterial Agents↗