Mechanisms for the Benzoylation of 2-Aminopyridine

1979 ◽  
Vol 32 (2) ◽  
pp. 381 ◽  
Author(s):  
LW Deady ◽  
DC Stillman
Keyword(s):  
Acetic Anhydride ◽  
Benzoyl Chloride ◽  
Relative Rate ◽  
Direct Reaction ◽  
Ring Nitrogen ◽  
Derivatives Of

Relative rate studies on ring methyl-substituted derivatives of 2-aminopyridine in pyridine solvent show that reaction with benzoyl chloride gives monobenzoyl derivatives by direct reaction on the exocyclic nitrogen (N'). The reaction is analogous to acetylation with acetic anhydride. Reaction in acetone, however, gives, except for the 6-methyl compound, N',N?-dibenzoylamino compounds, even in the presence of excess of amine. The results are shown to be consistent with ring nitrogen benzoylation (N1), followed by rapid N'-benzoylation and intramolecular benzoyl rearrangement from N1 to N'.

THE ALCOHOLYSIS OF TRIALKYLALKOXYSILANES: PART II. THE PREPARATION AND CHEMISTRY OF METHYL 2,3,4-TRI-O-TRI-METHYLSILYL-α-D-GLUCOPYRANOSIDE

1965 ◽  
Vol 43 (7) ◽  
pp. 2004-2011 ◽  
Author(s):  
D. T Hurst ◽  
A. G. McInnes
Keyword(s):  
Magnetic Resonance ◽  
Acetic Anhydride ◽  
Proton Magnetic Resonance ◽  
Benzoyl Chloride ◽  
Phenyl Isocyanate ◽  
High Yield ◽  
Aqueous Methanol ◽  
Trimethylsilyl Group ◽  
Acidic Catalysts ◽  
Derivatives Of

The trimethylsilyl group on the 6-position of methyl 2,3,4,6-tetra-O-trimethylsilyl-α-D-glucopyranoside is preferentially removed by methanolysis, using basic or acidic catalysts, giving methyl 2,3,4-tri-O-trimethylsilyl-α-D-glucopyranoside in high yield (>80%). Reaction of the latter with acetic anhydride, benzoyl chloride, or phenyl isocyanate produces the corresponding 6-substituted derivatives in quantitative yield. The trimethylsilyl residues from the latter compounds are hydrolyzed by 50% aqueous methanol with the concomitant formation of 6-O-acetyl, 6-O-benzoyl, or 6-carbanilate derivatives of methyl α-D-glucopyranoside in excellent yield. Chemical and proton magnetic resonance (p.m.r.) studies established the structure of methyl 2,3,4-tri-O-trimethylsilyl-α-D-glucopyranoside, and of subsequent derivatives prepared from this compound. Infrared and p.m.r. evidence is offered to support conclusions regarding the conformation of the groups or atoms attached to C6 and C5 of the glucoside residue in some of these compounds.

Analogs and derivatives of tenoxicam. 1. Synthesis and antiinflammatory activities of analogs with different residues on the ring nitrogen and the amide nitrogen

1987 ◽  
Vol 30 (4) ◽  
pp. 678-682 ◽  
Author(s):  
Dieter Binder ◽  
Otto Hromatka ◽  
Franz Geissler ◽  
Karl Schmied ◽  
Christian R. Noe ◽  
...  
Keyword(s):  
Amide Nitrogen ◽  
Ring Nitrogen ◽  
Derivatives Of

Approaches to the Synthesis of 5-Benzylidene-2-imidazolin-4-ones

1990 ◽  
Vol 43 (2) ◽  
pp. 367 ◽  
Author(s):  
RH Prager ◽  
C Tsopelas
Keyword(s):  
Acetic Anhydride ◽  
Aromatic Aldehydes ◽  
Darzens Reaction ◽  
Derivatives Of

Aromatic aldehydes , but not ketones, can be condensed with glycocyamidine . The corresponding alkylbenzylideneglycocyamidines may be made from glycidic esters by reaction with guanidine, followed by cyclization with acetic anhydride. A number of mono- and di -acetylated derivatives of 6,7-dihydropyrrolo[2,3-c]azepine-4,8(1H,5H)- dione have been prepared, but failed to undergo the Darzens reaction. Bromo- and iodo-2-arylazoimidazoles, protected on nitrogen by the methoxyethoxymethyl group, failed to undergo clean lithiation.

ChemInform Abstract: ON REACTIONS OF 6-METHOXY-1,2,3,4-TETRAHYDRO-BETA-CARBOLINONES-(1) AND THEIR DICHLOROPHOSPHORYLS WITH ACETIC ANHYDRIDE, SYNTHESIS OF 5-ACETYL DERIVATIVES OF THE BETA-CARBOLINE SERIES

1975 ◽  
Vol 6 (51) ◽  
pp. no-no
Author(s):  
L. N. YAKHONTOV ◽  
M. YA. URITSKAYA ◽  
O. S. ANISIMOVA ◽  
T. YA. FILIPENKO ◽  
K. F. TURCHIN ◽  
...  
Keyword(s):  
Acetic Anhydride ◽  
Derivatives Of

α-(4-Tolyl)dopamine, derivatives and analogues; Synthesis and pharmacological screening

1983 ◽  
Vol 48 (5) ◽  
pp. 1447-1464 ◽  
Author(s):  
Vladimír Valenta ◽  
Jiří Holubek ◽  
Emil Svátek ◽  
Antonín Dlabač ◽  
Marie Bartošová ◽  
...  
Keyword(s):  
Acetic Anhydride ◽  
Hydrobromic Acid ◽  
Benzoyl Chloride ◽  
Substitution Reactions ◽  
Low Degree ◽  
Anticataleptic Activity ◽  
Pharmacological Screening ◽  
Higher Doses ◽  
Hydroxyethyl Piperazine ◽  
Antiarrhythmic Effects

The ketone XIII, obtained by Friedel-Crafts reaction of toluene with homoveratroyl chloride, was converted by the Leuckart reaction to the formamido derivative IXb which was used as the starting product for the synthesis of amines IIIb-Vb. Reduction of the ketone XIII gave the alcohol XVI which was treated with hydrogen chloride and afforded the chloro compound XVII. Its substitution reactions with 1-methylpiperazine, 1-(2-hydroxyethyl)piperazine and 1-phenylpiperazine resulted in the piperazines VIb-VIIIb. Acylations of the amine IIIb with acetic anhydride and homoveratroyl chloride gave the amides Xb and XIb which, together with the formamide IXb, were subjected to the Bischler-Napieralski reaction. 3,4-Dihydroisoquinolines XXII-XXIV were obtained and reduced to the 1,2,3,4-tetrahydroisoquinolines XXVb-XXVIIb. Treatment of XXVIIb with formaldehyde afforded the berbine derivative XXVIII. Demethylation of the amine IIIb with hydrobromic acid resulted in the title compound IIIa. Similar demethylations of the dimethoxyamines IVb-VIIIb, XXVb and XXVIb led to the dihydroxyamines IVa-VIIIa, XXVa and XXVIa which are dopamine derivatives. Reaction of Va with benzoyl chloride gave the dibenzoate XXX. The CNS activities of the compounds prepared are of a low degree. Several of them (IIIa-VIa, IIIb-Vb, XXVb) show in higher doses signs of central stimulant action but only for compound IVa an antireserpine effect was proven. The expected anticataleptic activity was found only in a low degree with compound VIIIa; on the contrary, compounds IIIa and XXVa are procataleptogenic. Some compounds (IIIa, IXb, XXVIa, XXVIII) potentiated thiopental. In single cases local anaesthetic, spasmolytic, hypotensive, hypertensive, hypoglycaemic, diuretic and antiarrhythmic effects were observed.

Selective benzoylation of benzyl β-l-arabinopyranoside and benzyl α-d-xylopyranoside

1967 ◽  
Vol 45 (21) ◽  
pp. 2493-2500 ◽  
Author(s):  
T. Sivakumaran ◽  
J. K. N. Jones
Keyword(s):  
Benzoyl Chloride ◽  
Derivatives Of

Benzoylation of benzyl β-l-arabinopyranoside with 2.2 molar equivalents of benzoyl chloride gave benzyl 2,3-di-O-benzoyl-β-l-arabinopyranoside (65–70%) and benzyl 2,3,4-tri-O-benzoyl-β-l-arabinopyranoside (10–15%). Benzyl α-d-xylopyranoside, under similar conditions, gave benzyl 2,4-di-O-benzoyl-α-d-xylopyranoside (45%), benzyl 2,3-di-O-benzoyl-α-d-xylopyranoside (27%), benzyl 2,3,4-tri-O-benzoyl-α-d-xylopyranoside (15%), and benzyl 2-O-benzoyl-α-d-xylopyranoside (9%). Several new derivatives of benzyl β-l-arabinopyranoside and benzyl α-d-xylopyranoside have been prepared. These benzoates lead to the ready preparation of 4-O-substituted l-arabinose and d-xylose derivatives. These results are compared with those obtained for the selective benzoylation of hexopyranosides.

scholarly journals Enaminonitrile as Building Block in Heterocyclic Synthesis: Synthesis of Novel 4H-Furo[2,3-d][1,3]oxazin-4-one and Furo[2,3-d]pyrimidin-4(3H)-one Derivatives

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Manal M. El-Shahawi ◽  
Ahmed K. El-Ziaty
Keyword(s):  
Acetic Anhydride ◽  
Building Block ◽  
Benzoyl Chloride ◽  
Heterocyclic Synthesis ◽  
Elemental Analyses ◽  
Nitrogen Nucleophiles

2-Amino-4,5-diphenylfuran-3-carbonitrile 1 was utilized as building block for the construction of new furo[2,3-d]pyrimidin-4(3H)-one derivative 2 and 4H-furo[2,3-d][1,3]oxazin-4-one derivative 3 via treatment with acetic anhydride and benzoyl chloride, respectively. The 4H-furo[2,3-d][1,3]oxazin-4-one derivative 3 was transformed into novel furo[2,3-d]pyrimidin-4(3H)-ones 4–8, tetrazolylfuran derivative 10, and furo[3,2-d]imadazolone derivative 11 via reaction with various nitrogen nucleophiles. The structure features of the synthesized compounds were established from their spectral and elemental analyses.

Übergangsmetallkomplexe mit Nitroxidradikalen: Palladium-, Platin-, Pentamethylcyclopentadienyl-rhodium- und -iridium-Komplexe sowie α-Aminocarboxylatkomplexe mit Donor-haltigen Derivaten des 2,5-Dihydroimidazol-l-oxyls / Transition Metal Complexes of Nitroxide Radicals, Palladium, Platinum, Pentamethylcyclopentadienyl Rhodium and Iridium Complexes, and α-Aminocarboxylate Complexes with Derivatives of 2,5-Dihydroimidazole-l-oxyls

1998 ◽  
Vol 53 (1) ◽  
pp. 101-109 ◽  
Author(s):  
Frank Hintermaier ◽  
Sylvia Helding ◽  
Leonid B. Volodarsky ◽  
Karlheinz Sünkel ◽  
Kurt Polbom ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Molecular Structures ◽  
Iridium Complexes ◽  
X Ray Diffraction ◽  
Chelate Complexes ◽  
X Ray ◽  
Ring Nitrogen ◽  
Derivatives Of ◽  
Ring Nitrogen Atom ◽  
Palladium Platinum

2,5-Dihydroimidazoline-l-oxyl radicals I, II with imino substituents coordinate to Pd(II) and Pt(II) complexes with formation of the N,N chelate complexes 1-6. With oxygen containing substituents either monodentate N-coordination to give 8 or N ,O chelate formation to give 9 takes place, depending on the position of the oxygen atom relative to the ring nitrogen atom. With radicals III that also have the second ring nitrogen atom oxidized and the Rh(III) or Ir(III) complexes [Cp*MCl2]2 the O , O chelates 11 -13 could be obtained, while with Na2PdCl4 the heterocycle was destroyed with formation of a N,N chelate complex 10 of an α-nitrosooxime ligand. The orthopalladated 2,2,5,5 tetramethyl-4-phenyl-2,5-dihydroimidazoline-l-oxyl complex 7a reacts with several a-amino acidates under splitting of the dichloro bridge with formation of the C,N/N,O-bis-chelate complexes 7b-f. The molecular structures of 2 and 10 were determined by X-ray diffraction.

Syntheses of Enantiomeric N-(3-Hydroxy-2-phosphonomethoxypropyl) Derivatives of Purine and Pyrimidine Bases

1993 ◽  
Vol 58 (3) ◽  
pp. 649-674 ◽  
Author(s):  
Antonín Holý
Keyword(s):  
Benzoyl Chloride ◽  
Sodium Hydride ◽  
Cesium Carbonate ◽  
Amino Groups ◽  
Heterocyclic Base ◽  
Pyrimidine Bases ◽  
Derivatives Of ◽  
General Method

Methods of preparation of N-(3-hydroxy-2-phosphonomethoxypropyl) (HPMP) derivatives of (2S)- and (2R)-configuration (compounds I and XXVII, respectively) are described. The general method starts from the corresponding N-(2,3-dihydroxypropyl) derivatives which were converted either into the (R)-enantiomers XIII by reaction of the base with (R)-glycidol butyrate (XII) in the presence of cesium carbonate and subsequent methanolysis, or into the (S)-enantiomers XI by alkylation of the base with (R)-2,2-dimethyl-4-tosyloxymethyl-1,3-dioxolane (V) in the presence of the same reagent. The amino groups on the heterocyclic base in compounds XI and XIII were benzoylated by silylation followed by reaction with benzoyl chloride and the obtained N-benzoates XV and XVII on reaction with trityl chloride afforded the corresponding 3'-O-trityl derivatives XVI and XVIII. These compounds were condensed with bis(2-propyl) p-sulfonyloxymethylphosphonate (XXIII) in dimethylformamide in the presence of sodium hydride to give the fully protected diesters XXIV and XXVIII. These compounds could be selectively acid-hydrolyzed to remove the trityl group only under formation of compounds XXXV, or methanolyzed and then acid-hydrolyzed to remove the trityl and N-benzoyl groups and lead to compounds XXVI and XXX, or treated with bromotrimethylsilane to remove the trityl and 2-propyl group to give phosphonates of the type XXXI. All the three types of compounds were then converted into free phosphonates of the (S)-series (I) and the (R)-series (XXVII). Derivatives of cytosine (Ia, XXVIIa), adenine (Ib, XXVIIb), 2,6-diaminopurine (Ic, XXVIIc) and guanine (Id, XXVIId) were prepared. Condensation of the partially blocked adenine deriavtive XXXV with the tosyl derivative XXIII and subsequent deprotection afforded 9-(S)-(2,3-diphosphonomethoxy propyl)adenine (XLIII). Reaction of the same compound XXXV or its (R)-enantiomer XXXVIII with diethyl phosphonate , followed by deblocking, afforded 3'-O-phosphoryl derivatives (S)-HPMPA (XXXVII) and (R)-HPMPA (XL).

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