Reaktionen von Isochinolinium-Salzen mit Hydroxylamin-Derivaten, 3. Mitteilung. Mechanismus der Aminoxid-Bildung / Reactions of Isoquinolinium Salts with Hydroxylamine Derivatives, 3rd Communication. Mechanism of Amine Oxide Generation

1999 ◽  
Vol 54 (7) ◽  
pp. 913-922 ◽  
Author(s):  
H. Möhrle ◽  
R. Nießen
Keyword(s):  
Steric Hindrance ◽  
Nitrous Acid ◽  
Ring Opening ◽  
Amine Oxide ◽  
Stable Compound ◽  
Amine Oxides ◽  
Communication Mechanism ◽  
Hydroxylamine Derivatives ◽  
Moderate Yield

2-Methylpapaverinium iodide (1) reacted with hydroxylamine to papaverine-N-oxide (2), but without a detectable intermediate and only in moderate yield, caused by the steric hindrance of the 1-substituent. The ring opened product of 2-dinitrophenylisoquinolinium salt with hydroxylamine, the enamine-oxime 3b gave rise to a 3-substituted cyclic nitrone (6), when heated with triethylamine. This alkali-stable compound was transformed with acid quantitatively to isoquinoline-N-oxide (4). The enaminonitrile 9c, treated with triethylamine showed cyclization to the iminoisoquinoline 10, which by loss of nitrous acid produced the tetracyclic azaindole 11. The 2-methoxyisoquinolinium salt 16 was cleaved with O-methylhydroxylamine to the resistant di(O-methyloximes) (20a/b), unable to form the amine oxide 4. From these and former results, a mechanism for the ring opening of cycliminium salts and the recyclization to amine oxides was proposed.

Thienoisothiazoles. II. The synthesis of 5-alkylthioisothiazoles and the preparation of Thieno[3,2-d]isothiazole derivatives

1982 ◽  
Vol 35 (2) ◽  
pp. 393 ◽  
Author(s):  
FC James ◽  
HD Krebs
Keyword(s):  
Carboxylic Acid ◽  
Carbon Disulfide ◽  
Ring Opening ◽  
Hypophosphorous Acid ◽  
Bromo Derivative ◽  
Ring Open ◽  
Moderate Yield

Alkylation of the reaction product of sodium 3-iminobutyronitrile and carbon disulfide produces alkyl 2-cyano-3-iminodithiobutyrates (1) in moderate yield, which on iodine oxidation afford 5-alkylthio-3-methylisothiazole-4-carbonitriles (2b-e). Ethyl 4-amino-3-methylthieno[3,2-dliso- thiazole-5-carboxylate (3a) which was obtained by cyclization of ethyl 2-(4-cyano-3-methylisothiazol- 5-ylthio)acetate (2c) yields 3-methylthieno[3,2-d]isothiazole (3f) on deamination, hydrolysis and decarboxylation. This compound forms a 5-nitro and 5-bromo derivative. The position of the substituents was verified by synthesis. On reduction with hypophosphorous acid, 3-methylthieno- [3,2-d]isothiazole and some of its derivatives readily ring-open, yielding stable 3-acetimidoylthio-phen-2-thiols (4d-g), which are useful intermediates for the preparation of 3-acetyl-2-mercaptothiophen derivatives. Ring-opening of the isothiazole ring in 3-methylthieno[3,2-d]isothiazole (3f) and its 5-bromo derivative (3m) occurs during lithiation reactions, resulting in the formation of 3-acetyl-2-butylthiothiophen, isolated as the thiosemicarbazone (4c), and 3-acetyl-2-butylthio-thiophen-5-carboxylic acid (4b) respectively.

scholarly journals Synthesis of Octahydropyrano[2,3-d]Pyrimidine Derivatives via Tetrahydropyrano[3,2-e][1,3]Thiazolo[3,2-a]Pyrimidine and 2,6-Dichlorobenzonitrile Oxide

2018 ◽  
Vol 42 (6) ◽  
pp. 317-319
Author(s):  
Qing Zeng ◽  
Demin Ren ◽  
Aiting Zheng ◽  
Xiaofang Li
Keyword(s):  
Ring Opening ◽  
Crystallographic Analysis ◽  
Dipolar Cycloaddition ◽  
Pyrimidine Derivatives ◽  
X Ray ◽  
Moderate Yield

N1-substituted octahydro-1 H-pyrano[2,3- d]pyrimidines derivatives were prepared in moderate yield by the reaction of methyl [(4a RS,5 SR,10a RS)-5-aryl-2-oxo-3,4,4 a,10 a-tetrahydro-2 H,5 H-pyrano[3,2- e][1,3]thiazolo[3,2- a]pyrimidin-8(9 H)-ylidene]acetate and 2,6-dichorobenzonitrile oxide via a domino 1,3-dipolar cycloaddition/ring-opening/dethionation process. The structures of the products were characterised by spectroscopic and X-ray crystallographic analysis.

scholarly journals Ring Opening of Spiroepoxides Dithianedioxide with Bis-nucleophiles

2011 ◽  
Vol 3 (3) ◽  
pp. 575-586
Author(s):  
R. Ritmaleni ◽  
V. K. Aggarwal
Keyword(s):  
Amino Acid ◽  
Amino Alcohol ◽  
Ring Opening ◽  
Ring Opening Reaction ◽  
The Right ◽  
Morpholine Ring ◽  
Moderate Yield

This research was aimed to apply the spiroepoxide dithianedioxide for the synthesis of amino acid via ring opening of the spiroepoxide by bis-nucleophiles. First attempt was made to synthesize the bis-nucleophiles, amino alcohol, which was eventually used to the ring opening reaction of the spiroepoxide to produce the morpholine ring compound. The reaction was carried out in racemic and asymmetric method with moderate yield and high 99%. The last step produced amino acid that was still remained unsuccessful. However, it cannot be concluded yet whether the spiroepoxide dithianedioxide is the right intermediate for the synthesis of amino acid.Keywords:  Amino alcohol; Morpholine ring; Spiroepoxide dithianedioxide; Amino acid.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: 10.3329/jsr.v3i3.6746               J. Sci. Res. 3 (3), 585-596 (2011)

Deprotonation de N-oxydes d'amines aliphatiques: schéma réactionnel général et nouvelle synthèse de pyrrolidines

1985 ◽  
Vol 63 (3) ◽  
pp. 725-734 ◽  
Author(s):  
René Beugelmans ◽  
Leïla Benadjila-Iguertsira ◽  
Jacqueline Chastanet ◽  
Guillermo Negron ◽  
Georges Roussi
Keyword(s):  
Tertiary Amine ◽  
Amine Oxide ◽  
Secondary Amines ◽  
Lithium Diisopropylamide ◽  
Efficient Synthesis ◽  
Remarkable Property ◽  
Amine Oxides ◽  
Trimethylamine Oxide ◽  
First Time ◽  
Hydrolysis Of

Amine oxides, 1, 5, 10, 15, 21, 23, when treated by lithium diisopropylamide undergo deprotonation. Monodeprotonation gives rise either to secondary amines and benzaldehyde resulting from the hydrolysis of an intermediate immonium (I) or to hydroxylamines via a Stevens-like rearrangement observed for the first time on an amine oxide. Double deprotonation gives an immonium ylid (Y) which, depending upon the structure of the initial tertiary amine yields either "head to head" piperazines (biradical-like behavior of (DD)) or aziridines. The immonium ylid (Y5) derived from trimethylamine oxide, whose formation and reactivity are reported for the first time, has the remarkable property of undergoing cycloaddition reactions with unactivated olefins, leading to a new and efficient synthesis of various pyrrolidines.

Studies in Amine Oxide Rearrangement: Meisenheimer Rearrangement of m-Substituted Tertiary Amine Oxides.

ChemInform ◽  
2006 ◽  
Vol 37 (28) ◽  
Author(s):  
K. C. Majumdar ◽  
B. Roy ◽  
P. K. Basu ◽  
P. Biswas
Keyword(s):  
Tertiary Amine ◽  
Amine Oxide ◽  
Amine Oxides
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