ChemInform Abstract: One-Pot Preparation of Derivatives of the Unknown Fluoreno(2,3,4-ij)isoquinoline Ring from Conjugated Ketenimines by a Consecutive Electrocyclic Ring-Closure/Claisen Rearrangement/Intramolecular Diels-Alder Cycloaddition/Double Aromat

A new series of 5,6-dihydro-4H-1,2-oxazines were synthesized via hetero Diels-Alder reaction of α-nitrosolefins with derivatives of allylbenzene. α-Nitrosoolefins were generated from ketoximes by the action of chloramine-T and triethylamine.

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ChemInform Abstract: One-Pot Preparation of Pyrido(2,3,4-de)quinazolines and Benzo(de)(1,6) naphthyridines by a Consecutive Process Involving an Aza-Wittig/ Electrocyclic Ring Closure/Heterocumulene-Mediated Annelation or Intramolecular Diels-Alder Cycloa

ChemInform ◽

10.1002/chin.199223189 ◽

2010 ◽

Vol 23 (23) ◽

pp. no-no

Author(s):

P. MOLINA ◽

M. ALAJARIN ◽

A. VIDAL

Keyword(s):

Diels Alder ◽

Ring Closure ◽

One Pot

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Studies Towards the Synthesis of Salvinorin A

Australian Journal of Chemistry ◽

10.1071/ch05338 ◽

2006 ◽

Vol 59 (5) ◽

pp. 340 ◽

Cited By ~ 19

Author(s):

Anthony R. Lingham ◽

Helmut M. Hügel ◽

Trevor J. Rook

Keyword(s):

Stereoselective Synthesis ◽

Aqueous Media ◽

Alder Reaction ◽

Diels Alder ◽

Ring Closure ◽

Salvinorin A ◽

One Pot ◽

Diels Alder Reaction ◽

Opioid Receptor Agonist ◽

Ether Bridge

Salvinorin A 1, a psychoactive neoclerodane diterpenoid from the Mexican sage S. divinorum, has gained interest as a selective κ-opioid receptor agonist. Non-racemic 3-furylamines 9a and 9b have been prepared from (+)-pseudoephedrine and (–)-ephedrine for application in the stereoselective synthesis of the ketone ring of 1. Diels–Alder reaction of 9b with methyl acrylate in aqueous media, followed by selective ether bridge cleavage, has allowed access to the cyclohexenone 17 with preservation of stereochemistry at C2. A model route to the lactone ring has also been achieved through a one-pot deconjugation/esterification procedure of 2-bromocrotonyl chloride 20 to the furyl alcohol 19 followed by Reformatski-mediated ring closure.

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One-pot, Three-component Synthesis of 7H-[1,3,4]Thiadiazolo[ 3,2-a]pyridines from 2-Phenacyl-[1,3,4]thiadiazole Derivatives and Arylmethylene-cyanoacetic Acid Derivatives

Zeitschrift für Naturforschung B ◽

10.1515/znb-2007-1011 ◽

2007 ◽

Vol 62 (10) ◽

pp. 1298-1304 ◽

Cited By ~ 1

Author(s):

Imran Ali Hashmi ◽

Wolfgang Frey ◽

Ivo C. Ivanovc ◽

Willi Kantlehner

Keyword(s):

Ring Closure ◽

The Novel ◽

Pyridine Derivatives ◽

Cyanoacetic Acid ◽

One Pot ◽

X Ray ◽

Thiadiazole Ring ◽

Thiadiazole Derivatives ◽

Hydroxy Compounds ◽

Derivatives Of

Generally, arylmethylene-cyanoacetic acid derivatives react with enols and aromatic or heteroaromatic hydroxy compounds to afford 2-amino-4H-pyran derivatives of type 6. In contrast, a ring closure with the nitrogen atom of the thiadiazole ring occurs when 2-phenacyl-1,3,4-thiadiazoles (1a - d) act on derivatives of arylmethylene-cyanoacetic acid giving rise to the formation of 7H- [1,3,4]thiazolo[3,2-a]pyridine derivatives 5a - r. The same products are obtained if 2-phenacyl-1,3,4- thiadiazoles react with aromatic or heteroaromatic aldehydes and cyanoacetic acid derivatives. The constitution of the novel compounds 5 has been confirmed by an X-ray analysis of 5a.

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Orthoamides and iminium salts, LXXXIX. Reactions of N,N,N′,N′,N″,N″,N′″,N′″-octamethyl-acetylene-bis(carboxamidinium) tetrafluoroborate with nucleophilic reagents – new methods for the preparation of amidinium salts and ketene aminalsa

Zeitschrift für Naturforschung B ◽

10.1515/znb-2014-0204 ◽

2015 ◽

Vol 70 (4) ◽

pp. 225-241 ◽

Cited By ~ 2

Author(s):

Konstantin Drandarov ◽

Ioannis Tiritiris ◽

Willi Kantlehner

Keyword(s):

Ethyl Cyanoacetate ◽

Diels Alder ◽

Ring Closure ◽

Secondary Amines ◽

Mercaptoacetic Acid ◽

Iminium Salts ◽

Hydroxy Compounds ◽

Acidic Compounds ◽

Derivatives Of

AbstractThe acetylene-bis(carboxamidinium) salt 4 dehydrates carboxylic acids to the corresponding anhydrides, as the byproduct 2-oxo-but-2-en-amidinium salt 6b was isolated. Aromatic hydroxy compounds and 2-furyl-methylmercaptan add to the triple bond of the salt 4 to give 2-aryloxy- and 2-alkylmercapto-but-2-ene-bis(amidinium) salts 7–9. According to this reaction principle, 2-organoamino-buten-2-ene-bis(amidinium) salts 10 and 11 were prepared from 4 and primary and secondary amines, whereas 4-chlorobenzhydrazide reacted with 4 to give the imidazole-3-carboxamidinium salt 13. The reaction of CH2-acidic compounds as malononitrile or ethyl cyanoacetate with the bis(amidinium) salt 4 affords 2-cyanomethylene-but-3-enamidinium salts 15. With the CH-acidic diethyl 2-bromomalonate, compound 4 undergoes a Michael-initiated ring closure cyclopropenation reaction with further ring opening by the released Br– to the corresponding 2-diethoxycarbonylmethylene-3-bromo-but-3-enamidinium salt 18. Unlike cyclopentadiene and furane, the reaction of N-methylpyrrole and bis(amidinium) salt 4 does not lead to Diels–Alder [4 + 2] cycloadduct but to the Michael-type 1:1 adduct 20. Pyrrole- and thiophene-2-carboxamidinium salts 23–25 can be prepared from compound 4 and esters of glycine, N-methylglycine (sarcosine), and mercaptoacetic acid, respectively. The derivatives of quinoxaline-2-carboxamidinium salts 29 are accessible from aromatic 1,2-diamines and compound 4. The reaction of the CH2/NH-acidic cyanoacetamide with the bis(amidinium) salt 4 produced the 3-pyrroline-2-on derivatives 33.

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