The Duality of Mechanism for Nitration in Acetic Anhydride
11.06.2023 the addition of nitric acid to acetic anhydride) have been much used in studying aromatic nitration. The nature of the effective nitrating agent ...
FURAN Reaction with electrophiles - Protonation
HNO. 3. / H. 2. SO. 4. S. AcO NO2 conc. HNO3 Ac2O. X. X=S - Thiophene. X=O - Furan. X. NO2. H. AcO. NO2. X=S. X=O. O. NO2. H. AcO. H. Pyridine. O. NO2.
An Addition Reaction of Indane with Nitric Acid in Acetic Anhydride
indane is reacted with nitric acid and acetic anhydride. These adducts both mechanism cannot account for the formation of the trans isomer (4). We ...
Nitration of the tetramethylbenzenes in acetic anhydride. Formation
Side-chain (benzylic) nitrate derivatives are formed when the dihalotetramethylbenzenes in methylene chloride are nitrated with nitric acid. (9). Excellent
Product Class 3: N-Nitroamines
concd HNO3 Ac2O
Journal of Organic Chemistry
transfer electrophilic mechanism depending on the system and experimental conditions. HNO3/Ac2O; KNO3/H2SO4/DCM) and conditions (temperature
Kinetics of Aromatic Nitration in Acetic Anhydride1
nitric acid-acetic anhydride solutions at 25°. Upper 1.987. M HN03; lower Such a mechanism accounts for the first-order de- pendence of rate on nitric ...
34-Bis(4′-nitrofurazan-3′-yl)furoxan: a Melt Cast Powerful
However in such typical nitrating systems as HNO3/Ac2O
Facile access to nitroarenes and nitroheteroarenes using N
30.07.2019 HNO3/Ac2O. 0 °C to RT 6 h. 95% c. N. O. NO2. N. O. NO2. O. N. O. NO2. O. N. S. O ... radical mechanism
Nitration Chemistry in Continuous Flow using Acetyl Nitrate
Ac2O/HNO3 mixtures are on the other hand characterized by a certain explosive Mechanism VCH Publishers. Inc.
FURAN Reaction with electrophiles - Protonation
Page 2. Reaction with electrophiles - Nitration. Cannot use conc. HNO. 3. / H. 2. SO. 4. S. AcO NO2 conc. HNO3 Ac2O. X. X=S - Thiophene. X=O - Furan.
Heterocyclic Chemistry
c-HNO3. N. O. NO2. 100 °C. Electrophilic Substitution c-HNO3
The mechanism of nitration of anisole in the nitric acid - acetic
etfeot on the rate ot nitratiD~ in acetic anhydride caueed a very glightincreaee in the yield of aoetoxy product. Sulphuric acid• therefore
25.3 THE CHEMISTRY OF FURAN PYRROLE
https://www.saplinglearning.com/media/loudon/loudon5ech25sec03.pdf
Theoretical Investigation on the Mechanism and Design of Catalysts
Nitrolysis of HA using HNO3/NH4NO3/AcOH/Ac2O reagent gives a mixture of RDX and HMX. The yield of. RDX is usually higher than that of HMX. To increase.
THIOPHENES Reactions with electrophiles at C Preferably at C-2
Mechanism?? Page 11. C-metallation and further reactions. In the 2 / 5 pos.
Arkivoc Review Template
26-Dec-2016 In addition the proposed mechanisms of ipso-nitration ... indicated
Kinetics of Aromatic Nitration in Acetic Anhydride1
the mechanism of aromatic nitration for aqueous mixed acid and for nitric acid solutions in a number for mixtures of nitric acid with acetic anhydride.7.
[PDF] The mechanism of nitration of anisole in the nitric acid - acetic
acid-acetic anhydride mixturea He found that the acetoxylation: nitration rate ratio wae constant throughout each run and
[PDF] The mechanism of nitration of diphenylamine in the nitric acid
interpreted the results of their vapour pressure studies on the acetic anhydride - nitric acid system as evidence for the equilibria Ac2o + 21mo3
The Duality of Mechanism for Nitration in Acetic Anhydride
These observations relate to solutions prepared from pure nitric acid where [HNO] < ca lo4 M If the nitrating solutions were kept for several hours before
An Addition Reaction of Indane with Nitric Acid in Acetic Anhydride
indane is reacted with nitric acid and acetic anhydride These adducts both decompose on standing by loss of nitrous acid forming 5-acetoxyindane
Nitration of the tetramethylbenzenes in acetic anhydride Formation
Careful reaction of prehnitene with nitric acid in acetic anhydride at -60°C followed by quenching with ammonia at the same tempera-
[PDF] Furan derivatives 1? Role of acetic anhydride in nitration of 3-(2
Kinetic data of this reaction show the almost quantitative reaction between HNO3 and acetic anhydride during 60 min [15] and the nitration mixture prepared
Kinetics of Aromatic Nitration in Acetic Anhydride1
rium with HNO3 is suggested by Raman spectra for mixtures of nitric acid with acetic anhydride 7 Nitronium ion also has been detected in concen-
Salicylic Acid Nitration by Means of Nitric Acid/Acetic Acid System
The nitration of salicylic acid has been thus studied by using HNO3/H2SO4/H2O (the mixed acid) aque- ous HNO3 (70 by weight) HNO3/Ac2O/AcOH and HNO3/ AcOH
[PDF] FURAN Reaction with electrophiles - Protonation - UiO
Furanes as diene - one of the first DA examples Furan reacts with many dienophiles (alkenes alkynes allenes) exo isolated (termodyn favoured)
The least aromatic 5-membered ring
SO H H H H7.1 ppm
127 ppm
7.2 ppm
126 ppm
6.3 ppm
110 ppm
7.4 ppm
144 ppm
SO1.71Å
1.37Å
1.42Å
1.37Å
1.35Å
1.44Å
Reaction with electrophiles - Protonation
O O H HRing opening
O HMuch less basic than
ordinary ethers O H HMajor protonated form
Conc. H
2 SO 4Lewis acids (i.e. AlCl
3Decomp.
O H HH 2 O O OHHemiacetal
O OReaction with electrophiles - Nitration
Cannot use conc. HNO
3 / H 2 SO 4 SAcO NO
2 conc. HNO 3 , Ac 2 O XX=S - Thiophene
X=O - Furan
X NO 2 HAcO NO
2 X=S X=O O NO 2 H AcO HPyridine
O NO 2Halogenation
O Br 2Dioxane,
o C X Br H Br O Br H Br HSeen on
low temp NMR - HBr O Br Br 2 O Br Br can be isolated O MeO 2 C Br 2 O MeO 2 C Br Br O Br Br HOOH Br 2 HBr Br BrOH HO Br HOH HO see 15.14.1.2 O Br O Br Br1. t-Buli
2. H 2 O1. n-BuLi
2. DMF
O Br CHOReaction with electrophiles - Acylation
ODMF, POCl
3 O O "Vilsmeyer"Furfural
Also very readily available
by other routes OR'COCl or
(R'CO) 2 O BF 3 Et 2 O RR: H, Me
O R O R'Alkylation
Generally not practical (polyalkylation, polymerisation)Condensation with Aldehydes and Ketones
ORCHO, H
O OH RFurther react.
O OH CCl 3 stableFrom chloral
C.f. N H H , RCHO NHR=H, alkyl
H OH R H ±H N H R H OH 2 - H 2 O N H R HPolymer
Reaction with electrophiles - Condensation with imines / iminium ions CH 2 O, R 2 NH, H N R R OUnsubst furan: iminium ion must be preformed
O H N R R H O N R R X B(OH) 2 X=O X=S Ph 2 CHNH 2 HO 2 CCHO NH R O 2 C X X=O X=S CO 2 H Ph 2 HCHN ipso subst.Reaction with oxidating agents
O R 'R (Ox) R 'R O ODiv. ox. agents p 300
E-isomer in most casesO
Br 2 , MeOH O H H OMe MeOPb(OAc)
4 O OAc AcOReaction with nucleophiles
Some ex. on furans activated with -NO
2 groupMetallation and further react.
O n-BuLi Et 2O, Δ
O Li O n-BuLiTHF, -78
o C Br O Li > -40 o C n-BuLi TMEDA hexane, Δ O Li Li O Li OLi O Br LDA O Br Li (ODG) n-BuLi O CO 2 H LDA O CO 2 Li Li O CO 2 Li Li O Li B(OR) 3Hydrolysis
O B(OH) 3 BR 3 O B R R R Li I-IO R BR 2 H I I O RPd-cat couplings
O Li O MetAr-X (or related)
cat Pd O Ar O Br O Br BrAr-Met
cat Pd O Br Ar N RPd(OAc)
2 N H PdOAc R OAc N R PdOAc EWG N R EWG Heck + Pd(0)Cu(II)
c.f. O EWG cat. Pd O EWG O cat. Pd Ar-X O Ar like an alkene in HeckHeteroaryl-Heck
O ArAr-Pd-X
O O H Ar H PdXH-Pd-X
Cycloadditions
X O OO X O O O H HX=O: r.t.; 80%
X=S: 100 oC, 15kbar; 42%
Furanes as diene - one of the first DA examples
Furan reacts with many dienophiles (alkenes, alkynes, allenes) exo isolated (termodyn favoured) endo (kinetic prod.) With 1 O 2 O OO Oquotesdbs_dbs14.pdfusesText_20[PDF] hoboken fireworks 2020
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