Reactions of phenyl-substituted heterocyclic compounds. VII. Reagent-dependent orientation in the nitration of 4-phenylpyrimidine

1967 ◽  
Vol 45 (13) ◽  
pp. 1431-1437 ◽  
Author(s):  
Brian M. Lynch ◽  
Lizzie Poon
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Nucleophilic Addition ◽  
Heterocyclic Compounds ◽  
Trifluoroacetic Anhydride ◽  
Reaction Products ◽  
Heterocyclic Nitrogen

In the nitration of 4-phenylpyrimidine, the nature of the reaction products is strongly dependent upon the nitrating reagent. Mixed nitric and sulfuric acids yield 4-o- and 4-m-nitrophenylpyrimidines in the ratio 2:3, whereas nitric acid – trifluoroacetic anhydride yields 4-o-, 4-m-, and 4-p-nitrophenylpyrimidines in the ratio 45:29:26, and nitric acid – acetic anhydride yields 2,4-diacetoxy-1,3,5-trinitro-6-phenyl-1,2,3,4-tetrahydropyrimidine.An explanation of these findings involves the possibility of the addition of nitronium ion at the heterocyclic nitrogen, followed in some circumstances by nucleophilic addition.

REACTIONS OF PHENYL-SUBSTITUTED HETEROCYCLIC COMPOUNDS: V. NITRATIONS OF 1,3- AND 1,5-DIPHENYLPYRAZOLES

1964 ◽  
Vol 42 (7) ◽  
pp. 1605-1615 ◽  
Author(s):  
Brian M. Lynch ◽  
Yuic-Yung Hung
Keyword(s):  
Nitric Acid ◽  
Magnetic Resonance ◽  
Acetic Anhydride ◽  
Sulphuric Acid ◽  
Heterocyclic Compounds ◽  
Substituted 1

Dinitration of 1,3- or 1,5-diphenylpyrazole in sulphuric acid yields the corresponding di(p-nitrophenyl) compounds, while nitric acid–acetic anhydride yields the 4-nitro-1-p-nitrophenyl compounds.Mononitration at the 4-position occurs when the diphenylpyrazoles and several other 1-phenylpyrazoles are nitrated at 0° by nitric acid–acetic anhydride.Possible explanations of the dependence of orientation on the nature of the nitrating agent-are discussed.Nuclear magnetic resonance (n.m.r.) spectroscopy was used in demonstrating the structures of many of the nitration products, and a general discussion of the n.m.r. spectra of substituted 1-phenylpyrazoles is given.

REACTIONS OF PHENYL-SUBSTITUTED HETEROCYCLIC COMPOUNDS: II. NITRATIONS AND BROMINATIONS OF 1-PHENYLPYRAZOLE DERIVATIVES

1963 ◽  
Vol 41 (6) ◽  
pp. 1540-1547 ◽  
Author(s):  
Misbahul Ain Khan ◽  
Brian M. Lynch ◽  
Yuk-Yung Hung
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Heterocyclic Compounds ◽  
Electrophilic Substitution ◽  
Chloroform Solution ◽  
Pyrazole Ring ◽  
Conjugate Acid ◽  
Acetyl Nitrate ◽  
Silver Sulphate ◽  
Mixed Acids

Nitrations of 1-phenylpyrazole (I), 1-p-biphenylylpyrazole (II), and 1,5-diphenylpyrazole by "acetyl nitrate" (nitric acid – acetic anhydride) occur selectively in the 4-position of the pyrazole ring, as do brominations of I and II in chloroform solution. These results are in agreement with R. D. Brown's calculations of localization energies for electrophilic substitution in pyrazole.However, nitration of I by mixed acids at 12° yields 1-p-nitrophenylpyrazole, and bromination of I by bromine in concentrated sulphuric acid in the presence of silver sulphate yields 1-p-bromophenylpyrazole.The variations in orientation of substitution can be rationalized if the reacting species of I in strongly acidic solvents is the conjugate acid, in which the pyrazole ring is deactivated by protonation.

Synthesis of Cyclic Nitramines From Products of the Cyclocondensation Reaction of Guanidine With 2,3,5,6-Tetrahydroxypiperazine-1,4-dicarbaldehyde

1994 ◽  
Vol 47 (11) ◽  
pp. 2033 ◽  
Author(s):  
IJ Dagley ◽  
JL Flippenanderson
Keyword(s):  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Acetic Anhydride ◽  
Formic Acid ◽  
Guanidine Hydrochloride ◽  
Chloride Ion ◽  
Trifluoroacetic Anhydride ◽  
Cyclocondensation Reaction ◽  
Cyclic Nitramines ◽  
Cis Isomer

The reaction of 2,3,5,6-tetrahydroxypiperazine-1,4-dicarbaldehyde (1) with guanidine hydrochloride in hydrochloric acid can be controlled to give 2,6-diiminododecahydrodiimidazo[4,5-b:4′,5′-e] pyrazine (2a) or the cis isomer of 4,5-diamino-2-iminoimidazolidine (4). Compound (4) reacts with formaldehyde, or formic acid followed by reduction, to give 2-iminooctahydroimidazo[4,5-d] imidazole (7). Treatment of (2a) or (7) with nitric acid gives dinitro derivatives that were isolated as nitric acid salts of the cyclic guanidines. Reaction of the dinitro derivatives with nitric acid/acetic anhydride in the presence of chloride ion gives 4,8-dinitro-2,6-bis( nitroimino ) dodecahydrodiimidazo -[4,5-b:4′,5′-e] pyrazine (3a) and 1,3-dinitro-5-( nitroimino ) octahydroimidazo [4,5-d] imidazole (9). The reaction of (7) with nitric acid/ trifluoroacetic anhydride was controlled to give either the tetranitro or a dinitro bis ( trifluoroacetyl ) derivative of the corresponding bicyclic urea.

Ipso nitration. XIX. Formation of cyclohexadiene adducts from nitration of 4-ethyltoluene and 1,4-diethylbenzene in nitric acid and acetic anhydride

1978 ◽  
Vol 31 (6) ◽  
pp. 1241 ◽  
Author(s):  
A Fischer ◽  
GN Henderson ◽  
RJ Thompson
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Trifluoroacetic Acid ◽  
Trifluoroacetic Anhydride ◽  
Phenyl Acetate ◽  
Aqueous Methanol ◽  
Methyl Phenyl

Nitration of 4-ethyltoluene in acetic anhydride at -20° gives the diastereoisomers of 1-ethyl-4-methyl-4-nitrocyclohexa-2,5-dienyl acetate and of 4-ethyl-1-methyl-4-nitrocyclohexa-2,5-dienyl acetate. Similar nitration of 1,4-diethylbenzene gives the diastereoisomers of 1,4-diethyl-4-nitro-cyclohexa-2,5-dienyl acetate. Rearomatization of the adducts of p-ethyltoluene in trifluoroacetic acid-trifluoroacetic anhydride gives 4-ethyl-2-nitrotoluene from the 1-ethyl-4-methyl-4- nitro isomers and 4-ethyl-3-nitrotoluene from the 4-ethyl-1-methyl-4-nitro isomers. In aqueous methanol 2-ethyl- 5-methylphenyl acetate is obtained from the 1-ethyl-4-methyl-4-nitro isomers and 5-ethyl-2- methyl-phenyl acetate from the 4-ethyl-1-methyl-4-nitro isomers.

Ring Contractions of 3-Azido-4H-quinolizin-4-ones and 3-Azido-4H-azino[1,2 - x]pyrimidin-4-ones: a Novel Approach to 3-Aminoindolizines and their Aza Analogues

2008 ◽  
Vol 61 (2) ◽  
pp. 107 ◽  
Author(s):  
Simon Rečnik ◽  
Anton Meden ◽  
Branko Stanovnik ◽  
Jurij Svete
Keyword(s):  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Acetic Anhydride ◽  
Trifluoroacetic Anhydride ◽  
Reaction Products ◽  
Thermal Transformations ◽  
X Ray Diffraction ◽  
Ring Contraction ◽  
X Ray ◽  
Novel Approach

Thermal transformations of 3-azido-4H-quinolizin-4-ones 4a,b and 3-azido-4H-azino[1,2–x]pyrimidin-4-ones 4c,d, available from the corresponding heteroarylamines 2a–d, were studied. The reaction products were mostly dependent on the solvent. Thus, heating of 3-azido-1-cyano-4H-quinolizin-4-one (4a) in toluene afforded 2-(pyridin-2-yl)fumaronitrile 5a, whereas 3-amino-1-cyano-4H-quinolizin-4-one (8) was obtained on treatment of 4a in a mixture of toluene and trifluoroacetic anhydride. However, heating of 4a in acetic anhydride and in acetic acid resulted in a ring contraction to produce 3-(diacetylamino)indolizine-1-carbonitrile 6a and 3-(acetylamino)indolizine-1-carbonitrile 7a, respectively. Similarly, ring contractions took place on heating ethyl 3-azido-4-oxo-4H-quinolizin-1-carboxylate 4b and 3-azido-4H-azino[1,2–x]pyrimidin-4-ones 4c,d in acetic anhydride or acetic acid to produce the N-acetylated 3-aminoindolizine derivatives 6b, 7b and 3-aminoimidazo[1,2–x]azine derivatives 6c,d in 30–89% yields. The structures of compounds 5–8 were determined by NMR spectroscopy and X-ray diffraction.

Studies on the synthesis of heterocyclic compounds. XI. Cleavage of 1,3-benzodioxoles by magnesium bromide-acetic anhydride

1983 ◽  
Vol 20 (3) ◽  
pp. 703-707 ◽  
Author(s):  
Leonardo Bonsignore ◽  
Anna Maria Fadda ◽  
Giuseppe Loy ◽  
Antonio Maccioni ◽  
Gianni Podda
Keyword(s):  
Acetic Anhydride ◽  
Heterocyclic Compounds ◽  
Magnesium Bromide

Acetylation and Formylation of 3-Ferrocenylpyrroles

1999 ◽  
Vol 64 (1) ◽  
pp. 99-106
Author(s):  
Battsengel Gotov ◽  
Štefan Toma ◽  
Eva Solčániová
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Aluminum Chloride ◽  
Acetyl Chloride ◽  
Trifluoroacetic Anhydride ◽  
Acid Mixture ◽  
Chloride Method

Acetylations of 3-ferrocenyl-1-methylpyrrole as well as 3-cyano-4-ferrocenylpyrrole and 3-cyano-4-ferrocenyl-1-methylpyrrole were performed. The course of the acylation is highly dependent on the acylation agent, that is acetyl chloride/aluminum chloride (method A), trifluoroacetic anhydride-acetic acid mixture (method B) or acetic anhydride/Sc(OTf)3 (method C). Method A gives the acetylation on ferrocene moiety, method B affords the trifluoroacetylation on pyrrole moiety and method C affords pyrrole moiety acetylation. Vielsmeier-Haack formylation gives the products of substitution on pyrrole moiety.

Selective Nitroxylation of Adamantane Derivatives in the System Nitric Acid–Acetic Anhydride

2020 ◽  
Vol 56 (9) ◽  
pp. 1532-1539
Author(s):  
Yu. N. Klimochkin ◽  
E. A. Ivleva ◽  
I. K. Moiseev
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Adamantane Derivatives

Addition Reactions in the Nitration of Some Polycyclic Aromatic Compounds

1972 ◽  
Vol 50 (20) ◽  
pp. 3367-3372 ◽  
Author(s):  
A. Fischer ◽  
D. R. A. Leonard
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Nitro Group ◽  
Aromatic Compounds ◽  
Addition Reaction ◽  
Polycyclic Aromatic Compounds ◽  
Addition Reactions ◽  
Polycyclic Aromatic ◽  
Acetyl Nitrate

Reaction of 3-oxo-1,2,3,7,8,9,10,10a-octahydrocyclohepta[de]naphthalene with nitric acid in acetic anhydride gives two stereoisomeric 4-acetoxy-6a-nitro-3-oxo-1,2,3,4,6a,7,8,9,10,10a-decahydrocyclohepta[de]-naphthalenes as well as the expected nitro substitution products. Formation of these adducts from a substrate containing a meta-directing deactivating substituent shows that the 1,4-addition reaction of acetyl nitrate is more general than previously suspected. 1,4-Acetyl nitrate adducts are also formed from tetralin, benzsuberane, 5,6,7,8-tetrahydrocyclohepta[fg]acenaphthene, and 1,2,3,4,7,8,9,10-octahydrodicyclohepta[de,ij]naphthalene. Decomposition of the last two adducts gives in each case a product with the nitro group substituted into the alicyclic ring.

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