Reissert compound studies. XL. The first monocyclic reissert compounds

Pyridazine and pyrimidine have been reacted with trimethylsilyl cyanide and benzoyl chloride to give the first examples of Reissert compounds derived from monocyclic systems.     

An unexpected ring-opening in the reissert reaction on 2,3-diphenylquinoxaline-n-oxide.

When quinoxaline-N-oxide 1 is reacted with KCN and benzoyl chloride in water (the Reissert reaction) or methanol, the products are 2-,5- and 6- chloroquinoxaline (the latter being the major product: 42±6 %) and small amounts of 2-cyanoquinoxaline. Using three equivalents of trimethylsilyl cyanide instead of KCN, and dichloromethane as the solvent, leads to a 72 % yield of 2-cyanoquinoxaline. The reaction of trimethylsilyl cyanide and benzoyl chloride with 2,3-diphenylquinoxaline-N-oxide 2 leads to an unexpected ring-opening product 13; its structure is based on spectroscopic data and on an X-ray crystallographic analysis.     

Furopyridines. XXI. Synthesis of cyano derivatives of furo-[2,3-b]-, -[2,3-c]- and -[3,2-c]pyridine and their conversion to derivatives having another carbon-substituent

Cyanation of furo[2,3-b]-, -[2,3-c]- and -[3,2-c]pyridine N-oxides 1a, 1b and 1c by the Reissert-Henze method, reaction with benzoyl chloride and trimethylsilyl cyanide in dichloromethane and the reaction with trimethylsilyl cyanide and triethylamine in acetonitrile afforded 6-cyanofuro[2,3-b]- 2a , 7-cyanofuro[2,3-c]- 2b and 4-cyanofuro[3,2-c]pyridine 2c in moderate to excellent yield. The cyano group in 2a, 2b and 2c was converted to carboxamides 3a, 3b and 3c , ethyl imidates 5a, 5b and 5c and ethyl carboxylates 6a, 6b and 6c . Reaction of the N-oxides with trimethylsily bromide in acetonitrile gave the deoxygenated furopyridine 7a and 7d , bifuropyridyl 8b and 8c , and the N-oxide 9 of 8c .     

Reissert compound studies. LXIV. Reissert compound and other products from an isolated N-benzoylisoquinolinium triflate salt

In the presence of trimethylsilyl trifluoromethanesulfonate, a methylene chloride solution of isoquinoline and benzoyl chloride gave N-benzoylisoquinolinium triflate ( 3 ) and N-H-isoquinolinium triflate ( 4 ). Depending on the reaction conditions, reaction of 3 may occur on the isoquinoline ring yielding a Reissert compound and 1,2-dihydroisoquinoline species. Otherwise, reactions transpire on the carbonyl of 3 to give an amide, an ester, and an anhydride.     

Reissert compound studies. XLI. Synthesis and reactions of the pyrrolo[1,2-α]quinoxaline reissert compound and its analogs

Reaction of pyrrolo[1,2-α]quinoxaline, either by the phase-transfer catalyst method or by the trimethylsilyl cyanide method, yielded the Reissert compound, 5-benzoyl-4-cyano-4,5-dihydropyrrolo[1,2-α]quinoxaline. This Reissert compound rearranged to 4-benzoylpyrrolo[1,2-α]quinoxaline upon sodium hydride treatment. It also underwent methylation with methyl iodide and sodium hydride. A few Reissert analogs of the pyrroloquinoxaline were also prepared and their reactions studied.     

Pyridazines. XXV. Formation of 2-benzoyl-2,5-dihydro-3-pyridazinecarbonitrile derivatives in the reissert reaction of pyridazines

Pyridazines 1a, b on treatment with potassium cyanide/benzoyl chloride in a mixed solvent system gave 2-benzoyl-2,5-dihydro-3-pyridazinecarbonitriles 3a, b together with products resulting from attack of one mole of cyanide ion and three moles of benzoyl chloride ( 5a, b ). The structures of these novel compounds are proved. A plausible reaction mechanism is proposed, involving rearrangement of initially formed 2a, b into 3a, b . Furthermore, the synthesis of the pyridazine Reissert compound 2a is reported.     

Reissert compound studies. LXVII. The pyrido[3,4-b]pyrazine reissert compound

The pyrido[3,4-b]pyrazine systems investigated were found to form Reissert compounds in the presence of an acyl halide (or chloroformate) and trimethylsilyl cyanide. Only the mono Reissert compounds were isolated. In the case of 2,3-diphenylpyrido[3,4-b]pyrazine ( 7 ), its reaction with benzene sulfonyl chloride and trimethylsilyl cyanide gave 5-cyano-2,3-diphenylpyrido[3,4-b]pyrazine ( 16 ). Alkylation of the Reissert compound 11 and analog 12 either directly gave the alkylated hetercyclic base or the alkylated Reissert analog compound.     

Reissert compound studies. XXXIX. A novel approach to the berbine and 6-azaberbine systems and related derivatives of ellipticine

A new synthetic method for the construction of the berbine, 6-azaberbine, and indoloberbine ring skeletons is reported. Treatment of heterocyclic bases such as isoquinolines, phthalazines, and ellipticine with 2-chloromethylbenzoyl chloride and trimethylsilyl cyanide gave the corresponding Reissert compounds. Treatment of these Reissert compounds with sodium hydride resulted in intramolecular cyclization with loss of hydrogen cyanide.     

Reaction of <Emphasis Type="Italic">N,N</Emphasis>′-bis(trimethylsilyl)dicyandiamide with bis(η<Superscript>5</Superscript>-cyclopentadienylvanadium) dichloride

1,3,5-Tris[bis(η⁵-cyclopentadienyl)chlorovanadium]melamin is prepared in high yield by the reaction of N,N′-bis(trimethylsilyl)dicyandiamide with bis(η⁵-cyclopentadienylvanadium) dichloride in tetrahydrofuran. As side products, trimethylchlorosilane and cyclopentadiene formed. Reaction of N,N′-bis(trimethylsilyl) dicyandiamide with benzoyl chloride results in the formation of tris(benzoyl)melamin.     

Reactions of N-1(2,2-dichloroalkylidene)amines with potassium cyanide: synthesis of β-chloro-α-cyanoenamines, α-chloroimidates and 2-amino-5-cyan

Reaction of N-1(2,2-dichloroalkylidene)amines, prepared by chlorination of aliphatic aldimines with N-chlorosuccinimide, with excess of potassium cyanide in methanol gave β-chloro-α-cyanoenamines. When the reaction was carried out for a longer period, α-chloroimidates were isolated (except for N-t-Bu compounds). Reaction of the α-chloroaldimines with potassium cyanide in dimethylsulphoxide at 70° gave 1,2-dicyanoenamines while at 120° 2-amino-5-cyanopyrrols were produced via 1,3-dicyanoenamines. The reaction mechanisms are discused.     

Organometallic derivatives V. The lithiation of ferrocenylmethyl cyanide

Ferrocenylmethyl cyanide has been dilithiated with n-butyllithium and condensation of the lithiated intermediate with benzyl chloride gave α,α-dibenzylferrocenylmethyl cyanide. The lithioferrocene was also condensed with methyl iodide, butylbromide and 1,2-dichloroethane to give the corresponding α-disubstituted ferrocenylmethyl cyanides. The reactions of these α-disubstituted ferrocenylmethyl cyanides with n-butyllithium and lithium aluminium hydride have been investigated.     

Sur l'acylation des métylfuorènes I. Benzoylation et acétylation du méthyl-1-fluorène

Benzoylation and acetylation of 1-methylfluorene according Friedel-Crafts in carbon disulfide with aluminium chloride yielded the corresponding 2-acyl derivatives. By oxydation the benzoyl derivative gave 2-benzoyl-9-oxo-fluorene-1-carboxylic acid, cyclizable into 1,2-phthalyl-fluorenone.     

Pyrazine nucleoside analogs. Synthesis and reactions of some 5-thio-substituted pyrazines

5-Benzylthio-1,2-dihydro-2-oxopyrazine ( 8 ) was prepared from 2-amino-5-bromopyrazine by sequential treatment with sodium thiobenzylate and diazotization. Condensation of the silyl derivative of 8 with a protected 2-deoxyribofuranosyl chloride gave α and β anomers of 5-benzylthiopyrazine nucleosides. Reaction of 2,5-dichloropyrazine 4-oxide with sodium thiobenzylate followed by hydrolysis gave 5-benzylthio-1,2-dihydro-2-oxopyrazine 4-oxide ( 16 ).     

Unexpected Pt(II) migration between the calixarene oxygen atoms

Reaction between the 1,3-bis(trimethylsilyl) ether of calix[4]arene and platinum(II) difluoro complexes unexpectedly results in the formation of the 1,2-bridging platinum(II) calixarene complex, which, upon treatment with 2 equiv of acyl chloride, reinstates the 1,3-disubstitution pattern in the calixarene moiety.     

Trimethylsilyl Cyanide Addition to Carbonyl Compounds Under Neutral Condition Catalyzed by Iodine

Reaction of trimethylsilyl cyanide with aliphatic or aromatic aldehydes and ketones in the presence of a catalytic amount of elemental iodine produced the corresponding cyanohydrin trimethylsilyl ethers in very short time and high yields.     

Furopyridines. XVII . Cyanation,chlorination and nitration of furo[3,2-b]pyridine N-oxide

The N-oxide 2 of furo[3,2-b]pyridine ( 1 ) was cyanated by the Reissert-Henze reaction with potassium cyanide and benzoyl chloride to give 5-cyano derivative 3 , which was converted to the carboxamide 4 , carboxylic acid 5 , ethyl ester 6 and ethyl imidate 8 . Chlorination of 2 with phosphorus oxychloride yielded 2-9a , 3- 9b , 5- 9c and 7-chloro derivative 9d . Reaction of 9d with sodium methoxide, pyrrolidine, N,N-dimethylformamide and ethyl cyanoacetate afforded 7-methoxy- 10 , 7-(1-pyrrolidyl)- 11 and 7-dimethylaminofuro[3,2-b]pyridine ( 14 ) and 7-(1-cyano-1-ethoxy-carbonyl)methylene-4,7-dihydrofuro[3,2-b]pyridine ( 12 ). Nitration of 2 with a mixture of fuming nitric acid and sulfuric acid gave 2-nitrofuro[3,2-b]pyridine N-oxide ( 15 ).     

Synthesis of 13-azaequilenin analogs from 1,2-dihydro-4-methyl-benz(f)isoquinolines

Reaction of 1,2-dihydro-4-methyl-benz(f) isoquinolines with methyl acrylate and oxalyl chloride gave the corresponding tetracyclic compounds, while with chloroacetyl chloride an enamide was obtained which could not be cyclised thermally.     

Quino[1,2-c]quinazolines. II. Synthesis of 12,13-dihydro-11bH-quino-[1,2-c]quinazolines via the versatile intermediates 2-(2-amino-4,5-dimethoxyphenyl)-6,7-disubstituted-1,2,3,4-tetrahydroquinolines

The versatile intermediates 2-(2-amino-4,5-dimethoxyphenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroquinoline ( 2a ) and 6-(2-amino-4,5-dimethoxyphenyl)-5,6,7,8-tetrahydro[1,3]dioxolo[4,5-g]quinoline ( 2b ) were used in the preparation of a wide variety of 12,13-dihydro-11bH-quino[1,2-c]quinazolines by reaction with triethyl orthoformate, cyanogen bromide, urea and carbon disulfide in pyridine. Reaction of the thio and keto products with methyl iodide and phosphorus oxychloride, respectively, gave the requisite methylthio and chloro derivatives. Novel Reissert type reactions occurred when the intermediates 2a,b were reacted with acetic anhydride or benzoyl chloride. The attempted dehydrogenation of 12,13-dihydro-2,3,9,10-tetramethoxy-11bH-quino[1,2-c]quinazoline ( 3a ) is also reported.     

Reissert Compound Studies. LXI. Preparation and Reactions of Quinazoline Di-Reissert Compounds

Various di-Reissert compounds and analogs were prepared from quinazoline by use of trimethylsilyl cyanide together with a catalytic amount of anhydrous aluminum chloride. Reactions of these quinazoline di-Reissert compounds are reported.     

Pyrimido[5,4-b]quinolines. III. Synthesis of 10-alkyl-substituted 10-deazaalloxazines

A general method for the synthesis of 10-alkyl-substituted 10-deazaalloxazines (VIII) and the related chemistry are described. 4-Alkyl-substituted 3-aminoquinolines (IV) were reacted with benzoyl chloride and potassium cyanide in methylene chloride-water mixture to obtain Reissert compounds (V) which were hydrolyzed with a mixture of hydrobromic acid and acetic acid, and subsequently with 20% potassium hydroxide to give the corresponding 3-aminoquinaldic acids (VII). Cyclization with urea gave the 10-deazaalloxazines (VIII). Oxidation, hydroxylation and alkylation reactions of the 10-methyl derivatives (VIIIa,b) and of their quinaldic acid precursors are also reported.