Acyl Nitroso Compounds Research Articles

ChemInform Abstract: Short Synthesis of 14β‐Acylaminocodeinones from the Cycloadducts of Thebaine and Acylnitroso Compounds.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Reactions of Acyl Nitroso Compounds with Amines: Production of Nitroxyl (HNO) with the Preparation of Amides.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Short Synthesis of 14β-Acylaminocodeinones from the Cycloadducts of Thebaine and Acylnitroso Compounds

R. I. Gourlay and G. W. Kirby, J. Chem. Res. (S), 1997, 152 DOI: 10.1039/A608557A

Reactions of acyl nitroso compounds with amines: Production of nitroxyl (HNO) with the preparation of amides

Oxidation of hydroxamic acids in the presence of amines generates nitrous oxide (N 2O) and the corresponding amide. The identification of N 2O suggests the intermediacy of nitroxyl (HNO). Retro-Diels Alder dissociation of cyclopentadiene-acyl nitroso compound cycloadducts releases N 2O with amide formation.

General access to polyhydroxylated nortropane derivatives through hetero diels-alder cycloaddition. Part II: Synthesis of (±) calystegine B 2.

Calystegine B 2 was prepared by the intramolecular cyclisation of a polyhydroxylated 4-amino-cycloheptanone. This intermediate results from a heteroycloaddtion between an acylnitroso compound and a cyclohepta-1,3-diene. The diene is in turn obtained from iron-complexed tropone.

Electrophilic amination of 2-azadienes

2-Azadienes 1 bearing a trialkylsilyloxy group on position 3 can be regarded as carboxylic acid synthons. Their cycloadditions with several classes of nitroso compounds have been studied in details as well as the transformation of the adducts into α-amino acids. This study showed that arylnitroso compounds such as nitrosobenzene reacted with 2-azadienes to give adducts that are potential precursors of α-N-arylamino acids. We have outlined an important limitation to the use of α-chloronitroso compounds. They are not compatible with highly functionalized dienes like 2-azadienes. On the other hand α-cyanonitroso and acylnitroso compounds reacted with azadienes to give adducts which were readily converted into α-amino acid derivatives.

Stereoselective total synthesis of (–)-pumiliotoxin C by an aqueous intramolecular acylnitroso Diels–Alder approach

A chiral approach to (–)-pumiliotoxin C based on an aqueous intramolecular acylnitroso Diels–Alder reaction is described. Upon treatment of the (S)-1,3-diene hydroxamic acid 19, available from L-malic acid, with Pr4NIO4 under the aqueous conditions, the in situ generated acylnitroso compound 19 was subjected to intramolecular [4 + 2] cycloaddition to yield the trans-1,2-oxazino lactam 21 with significantly increased diastereoselectivity in comparison with the same cycloaddition conducted in a chloroform solution. Subsequent addition of the propyl side chain was achieved by means of a tandem Grignard reaction–NaBH3CN reduction in a completely stereocontrolled manner. The bicyclic 1,2-oxazine 26 thus obtained was converted into the all-cis-decahydroquinoline 34 by sequential reductive N–O bond cleavage, aldol condensation of the diketone 31 and hydrogenation of the octahydroquinolone 33. Clemmensen reduction of 34, followed by LiAlH4 reduction, provided a ca. 2 : 1 epimeric mixture of α-methyl and β-methyl isomers 36 and 37, and subsequent debenzylation converted the major isomer 36 into 5-epi-pumiliotoxin C 2. On the other hand, 34 underwent LiAlH4 reduction followed by Swern oxidation to afford a 1.2 : 1 epimeric mixture of the decahydroquinolones 39 and 41. Equilibrium control of this epimeric mixture by prolonged heating with Zn(OTf)2 followed by treatment with ethane-1,2-dithiol resulted in the exclusive formation of the thermodynamically more stable β-methyl epimer 43 as a single isomer, which was converted into (–)-pumiliotoxin C 1 by desulfurization and debenzylation.

General access to polyhydroxylated nortropane derivatives through hetero diels -alder cycloaddition

Title compounds were prepared by the intramolecular cyclisation of 4-aminocycloheptanones as the key step. The functionalisation of the iron-complexed tropone gave cyclohepta-1,3-dienes. The 4-aminocycloheptanones result from a heterocycloaddition between an acylnitroso compound and a eyclohepta-1,3-diene.

Stereoselective cycloadditions of chiral acyl-nitroso compounds; hydrolytic reactions of a clyclopentadiene adduct

Treatment of the adduct between the acyl nitroso intermediate derived from (R)-α-hydroxyphenylacetohydroxamic acid and cyclopentadiene, 1, with dilute aqueous acid provides a high yield of the cyclopentene 2 hydrochloride, suitable for further, synthetically useful transformations.

Stereoselective cycloadditions of chiral acyl-nitroso compounds; palladium(0) catalyzed allylic displacement with concomitant loss of the chiral auxiliary

The methylated diacetate 4, derived from the readily available hydroxamic acid 1, undergoes Pd o catalyzed nucleophilic allylic displacement under conditions which also result in the removal of the chiral auxiliary and its replacement with an easily removed acetyl group.

Stereoselective cycloadditions of chiral acyl-nitroso compounds; unexpected formation of an oxazolidinone

On treatment with either N-phenyltrifluoromethanesulphonimide or p-toluenesulphonyl chloride and base, hydroxamic acid 3 provides the oxazolidinone 4 in moderate yield, probably by a pathway involving fragmentation; Boc derivative 8 is suitable substrate for Pd o catalyzed nucleophilic displacement.

ChemInform Abstract: Amino Acid Derived Chiral Acyl Nitroso Compounds: Diastereoselectivity in Intermolecular Hetero Diels‐Alder Reactions.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Asymmetric syntheses of novel amino acids and peptides from acylnitroso-derived cycloadducts

Oxidative cleavage of cycloadducts of amino acid-derived acylnitroso compounds produces peptides in which the carbon framework of the new carboxy terminal amino acid was generated from cyclopentadiene.

Total synthesis of (−)-pumiliotoxin C by aqueous intramolecular acylnitroso Diels-Alder approach

A chiral approach to (−)-pumiliotoxin C via a stereoselective intramolecular hetero Diels-Alder reaction of a chiral acylnitroso compound performed in an aqueous medium is described.

Amino Acid-Derived Chiral Acyl Nitroso Compounds: Diastereoselectivity in Intermolecular Hetero Diels-Alder Reactions

The diastereoselectivities of chiral acyl nitroso dienophiles derived from optically pure N-protected α-amino hydroxamic acids have been de- termined in intermolecular hetero Diels-Alder reactions. The cycloaddi- tion reactions afforded synthetically useful quantities of functionally rich, optically pure cycloadducts, useful for the preparation of a vari- ety of compounds of potential biological interest. Molybdenum hexacar- bonyl reduction of the cycloadducts gave optically pure allylic alco- hols. Osmium tetraoxide-catalyzed dihydroxylation of several bis-ally- lically substituted intermediates gave only the diastereomerically pure diols corresponding to naturally occurring 2',3'-dihydroxynucleoside analogs

Spin trapping of methyl radicals by the acyl nitroso compound Ph--C(= O)NO formed in the photochemical reaction between benzohydroxamic acid, dimethyl sulfoxide and hydrogen peroxide. An EPR study.

By the use of EPR spectroscopy, it has been shown that acyl nitroso compounds can act as spin traps for short-lived radicals with the formation of acyl aminoxyl radicals. The reaction was studied for the system benzohydroxamic acid [Ph--C(= O)N(H)]-dimethyl sulfoxide-hydrogen peroxide. The acyl aminoxyl radicals appeared almost immediately when the reaction mixture was irradiated in situ in the EPR cavity with UV light. The trapping reaction involved two photochemical reactions, i.e. the oxidation of the hydroxamic acid to the acyl nitroso compound Ph--C(= O)NO, and the formation of methyl radicals from dimethyl sulfoxide. The EPR spectra are superpositions of the spectra of two species of acyl aminoxyl radicals, i.e. the radicals Ph--C(= O)N(O.)H formed by oxidation of the parent benzohydroxamic acid, and the radical Ph--C(= O)N(O.)CH3, formed by trapping of methyl radicals.

Enhanced stereoselectivity in aqueous intramolecular hetero Diels-Alder cycloaddition of chiral acylnitroso compounds

In an aqueous medium, intramolecular hetero Diels-Alder cycloadditions of the chiral acylnitroso compounds, generated from the chiral hydroxamic acids by in situ periodate oxidation, shows a pronounced enhancement of the trans selectivity compared with the results obtained by employing nonaqueous conditions.

ChemInform Abstract: Asymmetric Induction in the Diels‐Alder Reactions of α‐Hydroxy Acyl Nitroso Compounds.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Asymmetric induction in the Diels–Alder reactions of α-hydroxy acyl nitroso compounds

The hydroxamic acids 7, derived from a series of α-hydroxy acids 5, have been oxidised with periodate to form transient, chiral acyl nitroso compounds 8, which were trapped in situ with cyclopentadiene and cyclohex-1,3-diene to give mixtures of diastereoisomeric, Diels–Alder cycloadducts 9 and 10, respectively. Cycloaddition at 0 °C occurred with moderate stereoselectivity, e.g. both the mandeloyl nitroso compound 8a with cyclopentadiene and the tert-butylglycoloyl nitroso compound 8d with cyclohexadiene gave ca. 5:1 mixtures of diastereoisomers. Much higher diastereoselectivities (cycloadduct ratios ca. 10:1 for 9a, 9d and 10d) were observed at –78 °C. The mandeloyl nitroso compound 8a, which can form an intramolecular hydrogen bond between the hydroxy and nitroso groups, showed higher stereoselectivities than its O-methyl ether 8b. The major cycloadduct 13a of the (S)-mandeloyl nitroso compound 12 and cyclohexadiene was degraded to the bicyclic oxazine 15 of known absolute configuration. Formation of the cycloadduct 13a as the major product is consistent with preferential endo addition of the hydrogen bonded nitroso compound 12 from the face anti to the phenyl group.

Diastereoselective [4+2] Cycloadditions of Acyl Nitroso Compounds

A highly diastereoselective route to unsaturated amino alcohol derivatives has been developed that features the [4+2] cycloaddition of chiral acyl nitroso compounds to a variety of conjugated dienes; a useful oxidative method for generating acyl nitroso compounds from the corresponding hydroxamic acids under very mild conditions was also discovered.