THE INFLUENCE OF SUBSTITUENTS ON THE EASE AND DIRECTION OF RING OPENING IN THE LiAlH4–AlCl3 REDUCTIVE CLEAVAGE OF SUBSTITUTED 1,3-DIOXOLANES

1964 ◽  
Vol 42 (5) ◽  
pp. 990-1004 ◽  
Author(s):  
B. E. Leggetter ◽  
R. K. Brown
Keyword(s):  
Electron Donor ◽  
Electron Acceptor ◽  
Ring Opening ◽  
Room Temperature ◽  
Reductive Cleavage ◽  
The Other ◽  
Ring Cleavage ◽  
Other Hand ◽  
Influence Of Substituents

The room temperature hydrogenolysis by LiAlH4–AlCl3 of ether solutions of a number of 1,3-dioxolanes has been studied.Electron donor substituents on the C2 atom of the ring accelerate while electron acceptor substituents on C2 retard the reductive ring cleavage. The same effect but to a lesser extent is observed when these substituents are attached to the C4 or C5 atom of the ring.When electron donor substituents are attached to C4, ring cleavage occurs predominantly at the C2—O bond remote from the C4 position. On the other hand, electron-withdrawing groups attached to C4 give predominantly scission of the C2—O bond closer to the C4-substituted position. In contrast to this marked control over the direction of ring cleavage exhibited by substituents on C4, those on C2 generally have little or no effect on the direction of ring opening.A mechanistic interpretation of the results is presented.

scholarly journals Synthesis of spiro[dihydropyridine-oxindoles] via three-component reaction of arylamine, isatin and cyclopentane-1,3-dione

2013 ◽  
Vol 9 ◽  
pp. 8-14 ◽  
Author(s):  
Yan Sun ◽  
Jing Sun ◽  
Chao-Guo Yan
Keyword(s):  
Acetic Acid ◽  
Reaction Mechanism ◽  
Room Temperature ◽  
The Other ◽  
Other Hand ◽  
Three Component Reaction ◽  
High Yields

A fast and convenient protocol for the synthesis of novel spiro[dihydropyridine-oxindole] derivatives in satisfactory yields was developed by the three-component reactions of arylamine, isatin and cyclopentane-1,3-dione in acetic acid at room temperature. On the other hand the condensation of isatin with two equivalents of cyclopentane-1,3-dione gave 3,3-bis(2-hydroxy-5-oxo-cyclopent-1-enyl)oxindole in high yields. The reaction mechanism and substrate scope of this novel reaction is briefly discussed.

Diversification of α–Ketoamides via Transamidation Reactions with Alkyl and Benzyl Amines at Room Temperature

2021 ◽  
Author(s):  
Shweta Singh ◽  
Sureshbabu Popuri ◽  
Qazi Mohammad Junaid ◽  
Sabiah Shahul Hameed ◽  
Jeyakumar Kandasamy
Keyword(s):  
Room Temperature ◽  
The Other ◽  
Alkyl Amines ◽  
Other Hand ◽  
Wide Range

A wide range of N-tosyl α–ketoamides underwent transamidation with various alkyl amines in the absence of catalyst, base, or additives. On the other hand, transamidation in N-Boc α–ketoamides is achieved...

P-doped graphene-C60 nanocomposite: A donor–acceptor complex with a P-C dative bond

2022 ◽  
Author(s):  
Rabindranath Lo ◽  
Debashree Manna ◽  
Pavel Hobza
Keyword(s):  
Electron Acceptor ◽  
The Other ◽  
Acceptor Complex ◽  
Dative Bond ◽  
Other Hand ◽  
Doped Graphene ◽  
Donor Acceptor

Phosphorous-doped graphene can form a covalent dative bond with the electron acceptor, C60 molecule. On the other hand, C60 on graphene and N-doped graphene surfaces can only form vdW complexes....

scholarly journals Catalytic photoinduced electron transport across a lipid bilayer mediated by a membrane-soluble electron relay

2015 ◽  
Vol 51 (96) ◽  
pp. 17128-17131 ◽  
Author(s):  
B. Limburg ◽  
E. Bouwman ◽  
S. Bonnet
Keyword(s):  
Electron Transfer ◽  
Electron Transport ◽  
Lipid Bilayer ◽  
Electron Donor ◽  
Electron Acceptor ◽  
The Other

Unidirectional photocatalytic electron transfer from a hydrophilic electron donor encapsulated in the interior of a liposome, to a hydrophilic electron acceptor on the other side of the membrane, has been achieved using the simple membrane-soluble electron relay 1-methoxy-N-methylphenazinium (MMP+).

Arylhydrazonothiazolidinones: Ring Cleavage and Alkylation of the 5-Arylhydrazono Derivatives of Rhodanine and Isorhodanine

1979 ◽  
Vol 34 (3) ◽  
pp. 507-510 ◽  
Author(s):  
Nazmi A. Kassab ◽  
Sanaa O. Abd Allah ◽  
Said A. Elbahaii
Keyword(s):  
Hydrazine Hydrate ◽  
The Other ◽  
Ring Cleavage ◽  
Ethyl Bromoacetate ◽  
Other Hand ◽  
Alkyl Derivatives ◽  
Derivatives Of

Abstract The 5-arylhydrazono derivatives of rhodanine and isorhodanine were subjected to the action of hydrazine hydrate to afford the arylhydrazonomercaptomethyl-triazolinones (3) and -triazolinthiones (3) respectively. Treatment of 1 with benzylamine afforded thioxalic acid dibenzylamide (5). On the other hand treatment of 2 with the same reagent afforded the corresponding benzylimino derivatives (6).Alkylation of 1 and 2 with ethyl bromoacetate and chloroacetamide yielded the corresponding S-alkyl derivatives (7) and (8), respectively.

Langmuir-Blodgett films of One-dimensional Nanowires composed of Amphiphilic Tetrathiafulvalenes and Electron Acceptor

2008 ◽  
Vol 1144 ◽  
Author(s):  
Yoko Tatewaki ◽  
Junko Takizawa ◽  
Tatsuya Hatanaka ◽  
Mutsumi Kimura ◽  
Hirofusa Shirai
Keyword(s):  
Electron Acceptor ◽  
Room Temperature ◽  
The Other ◽  
Water Interface ◽  
One Dimensional ◽  
Langmuir Blodgett ◽  
Electrical Conductivities ◽  
Air Water Interface ◽  
Langmuir Blodgett Films ◽  
Mixed Layers

ABSTRACTWe found that novel amphiphilic tetrathiafulvalene (TTF; 1) organized into supramolecular assemblies by the addition of electron acceptor 2,3,5,6-tetrafluoro-7,7'f,8,8'f-tetracyano-p-quinodimethane (F4TCNQ) at the air-water interface. The assemblies on the air-water interface can be transferred onto the surface of mica and the morphologies of transferred films were investigated by AFM. The morphology of Langmuir-Blodgett films strongly depended on the ratio between 1 and F4TCNQ. Film of 1:1 mixture of 1 and F4TCNQ formed nanoscopic wires having an average dimension of 5.0 (height) × 70 (width) × 3000 (length) nm. On the other hand, the film of 2:1 mixture of 1 and F4TCNQ showed the mixed domains of wires and flat monolayers. Thus, the completely charge-transferred complex (1+)(F4TCNQ-) formed one-dimensional nanowires having a micrometer length. Room temperature electrical conductivities of cast film for 1:1 and 2:1 mixed layers of 1 and F4TCNQ were 2.4 × 10−4 and 8.0 × 10−5 S cm−1, respectively.

2-Aryloxytetrahydrofurans. Their Reductive Cleavage by Ether Solutions of AlH2Cl and their Cleavage and Rearrangement by Ether Solutions of AlCl3

1972 ◽  
Vol 50 (22) ◽  
pp. 3639-3647 ◽  
Author(s):  
P. C. Loewen ◽  
R. K. Brown
Keyword(s):  
Electron Donor ◽  
Bond Cleavage ◽  
Reductive Cleavage ◽  
Para Position ◽  
Ring Cleavage ◽  
Electrophilic Attack ◽  
Aryl Ring ◽  
Excellent Yield ◽  
Acid Catalyzed

The hydrogenolysis of 2-aryloxytetrahydrofurans by excess AlH2Cl gave, in excellent yield, only those products expected from exo C—O bond cleavage regardless of the nature of the substituent in the aryl ring. None of the 4-aryloxy-1-butanol, the product expected from ring cleavage, was detected. The reaction was very much faster than the corresponding AlH2Cl hydrogenolysis of 2-alkoxytetrahydrofurans which is known to give only ring cleavage products under similar conditions.Treatment of 2-aryloxytetrahydrofurans or pyrans with AlCl3 in ether, resulted in acid-catalyzed cleavage to the corresponding phenol and dihydrofuran or dihydropyran, the latter immediately forming polymeric products. For those 2-aryloxytetrahydrofurans or pyrans, unsubstituted, or substituted with electron donor groups in the aryl ring, another product was obtained which resulted from electrophilic attack of one protonated dihydrofuran or pyran on the ortho or para position of the phenol. These rearrangement products were also obtained in small amounts as byproducts when 2-aryloxytetrahydrofurans were hydrogenolyzed with insufficient AlH2Cl.

Record-Breaking Steric Crowding in Trialkylamines Prepared by Oxidative Ring Opening

Synthesis ◽  
2020 ◽  
Vol 52 (24) ◽  
pp. 3801-3810
Author(s):  
Klaus Banert ◽  
Manuel Heck ◽  
Andreas Ihle ◽  
Erik Michael ◽  
Richard Weber
Keyword(s):  
Ring Opening ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Model Compound ◽  
Ring Cleavage ◽  
Open Chain ◽  
Tert Butyl ◽  
Steric Crowding ◽  
Acid Catalyzed ◽  
Subsequent Acid

AbstractEpoxidation of olefinic heterocyclic amines and subsequent acid-catalyzed hydrolysis or alternatively the direct dihydroxylation with the help of osmium tetroxide led to diols, which underwent ring cleavage in the presence of lead tetraacetate to give 3-isopropyl-2,2,4,4-tetramethyl-3-azahexanedial and 3-tert-butyl-2,2,4,4-tetramethyl-3-azapentanedial. Whereas the former dialdehyde is a highly unstable model compound because of a rapid intramolecular aldol reaction, the latter product proves to be isolable at room temperature. Furthermore, this compound is the first open-chain tri-tert-alkylamine establishing in a new record of steric crowding in tertiary amines. Strong tendencies to a Hofmann-like elimination reaction or to ring-closing reactions were observed when the aldehyde units of 3-tert-butyl-2,2,4,4-tetramethyl-3-azapentanedial were transformed into other functionalities, since both types of reactions led to a significantly decrease of the steric stress.

Letters to the Editor

PEDIATRICS ◽  
1973 ◽  
Vol 52 (2) ◽  
pp. 309-309
Author(s):  
C. Warren Bierman
Keyword(s):  
Room Temperature ◽  
Skin Testing ◽  
The Other ◽  
Letters To The Editor ◽  
Other Hand ◽  
Number Of Patients ◽  
Testing Solution

Dr. Bergner is quite correct in pointing out that skin testing with a freshly prepared penicillin solution will select out only about 30% of patients who are anaphylacticly sensitive to penicillin.1 On the other hand, the use of a sterile solution of benzylpenicillin diluted with alkaline buffered saline (pH 7.6) and permitted to stand at room temperature for at least two weeks appreciably increases the number of patients so detected.2 We would agree that the availability of a penicilloyl polylysine (PPL) testing solution and a stabilized minor determinent mixture (MDM) would greatly enhance the armamentarium of the clinician to detect anaphylactic sensitivity to penicillin.3

PRECOCIOUS TERMINATION OF “OBLIGATORY” DIAPAUSE IN FIELD-COLLECTED PUPAE OF ANTHERAEA POLYPHEMUS

1968 ◽  
Vol 100 (2) ◽  
pp. 134-139 ◽  
Author(s):  
A. Mansingh ◽  
B. N. Smallman
Keyword(s):  
Adult Development ◽  
Room Temperature ◽  
The Other ◽  
Mortality Factor ◽  
Natural Mortality ◽  
Antheraea Polyphemus ◽  
Other Hand ◽  
Heavy Mortality

AbstractAntheraea polyphemus Cramer pupae, collected in early August, were found to maintain adult development at room temperature and natural daylength of late August and early September. These pupae had almost no coldhardiness, and heavy mortality occurred in the group of pupae stored at 6 °C. On the other hand, the pupae of A. polyphemus collected in late September were in diapause and were perfectly coldhardy. The possible relationship between the date of pupation and the incidence of diapause, and its significance as a natural mortality factor, is discussed.

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