bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on the syntheses of azole derivatives. Part II . Syntheses of N‐(1‐ or 2‐Substituted)indazolones via Diazotization
Authors: Kametani Tetsuji , Sota Kaoru , Shio Masahisa
Published: March 2009

Syntheses of 2,5‐disubstituted‐indazolones (Ixa–g) and 3‐hydroxy‐1‐substituted‐1H‐indazoles (XIVa,b) were achieved by diazotization of 2‐benzoylaniline (VIa–g) and N‐benzoylhydrazine (XIIa–c), respectively.
Studies on the syntheses of azole derivatives. Part III. Syntheses of 1‐Phenyl‐Δ2‐1,2,4‐triazolin‐5‐one and 4‐Phenyl‐Δ2‐1,3,4‐oxadiazolin‐5‐one Derivatives by Fusion of 1‐Phenyl‐2‐acylhydrazine with Urea
Authors: Kametani Tetsuji , Sota Kaoru , Shio Masahisa
Published: March 2009

Fusion of 1‐phenyl‐2‐acylhydrazine (III) with urea gave Δ2‐1,2,4‐triazolin‐5‐one and Δ2‐1,3,4‐oxadiazolin‐5‐one derivatives together with various by‐products. Furthermore, various derivatives were synthesized for the purpose of examination in a pharmacological screening test.
Synthesis of 4‐azatricyclo[4.3.1.13,8] undecane (4‐azahomoadamantane)
Authors: Narayanan V. L. , Setescak L.
Published: March 2009

Efficient routes for the synthesis of 4‐azahomoadamantane (V) via the Beckmann and Schmidt rearrangements are described. The lactam III is unusual in that it forms a stable crystalline hydrochloride IV.
Preparation and some reactions of 3‐oxazoline N‐oxides
Authors: Hansen Gary R. , Boyd Robert L.
Published: March 2009

Substituted 3‐oxazolines react with m‐chloroperoxybenzoic acid to give the corresponding 3‐oxazoline N‐oxides. These heterocyclic nitrones underwent molecular rearrangements, but would not react with 1,3‐cyclo‐addition type reagents.
The preparation of 1,2,4‐Triazines and 1,2,4‐Triazolines from substituted carboxamide hydrazones
Authors: Case Francis H.
Published: March 2009

Substituted carboxamide hydrazones have been condensed with 2,3‐butanedione and with glyoxal to form 1,2,4‐triazines; with benzaldehyde and pyridine‐2‐carboxaldehyde to yield 1,2,4‐triazolines.
Condensation of pyridoxal with the methyl ester of glycine
Authors: Korytnyk W. , Ahrens H.
Published: March 2009

Condensation of pyridoxal with the methyl ester of glycine gave the aminocoumarin analog 3‐amino‐8‐rnethyl‐2‐oxo‐2H‐pyrano[2,3‐c]pyridine‐5‐methanol (III), and not the expected aldimine. The structure of the compound was deduced by independent synthesis and by comparing its NMR spectrum with that of 3‐aminocoumarin. The new reaction provides routes for the synthesis of α4‐pyridoxylideneglycine and α4‐pyridoxyloxoacetic acid derivatives. It may also provide a model for irreversible inactivation of vitamin B6 in biochemical systems.
1,2,4‐Triazoles. XXV. The effect of pyridine substitution on the isomerization of s‐Triazolo[4,3‐a] pyridines into s‐Triazolo[1,5‐a] pyridines
Authors: Potts K. T. , Surapaneni C. R.
Published: March 2009

The isomerization of s‐triazolo[4,3‐a]pyridines into s‐triazolo[1,5‐a]pyridines is greatly facilitated by electron withdrawing nitro substituents in the pyridine ring and retarded by electron donating amino groups.
Investigation of some tetrazole derivatives of 1,8‐naphthyridines
Authors: Carboni S. , Da Settimo A. , Ferrarini P. L. , Ciantelli P. L.
Published: March 2009

Several tetrazole derivatives have been prepared from 7‐amino‐2‐hydroxy‐3‐phenyl‐1,8‐naphthyridine (Id). Evidence is presented to demonstrate that the tetrazole ring structure is the dominant species in the solid state and in alkaline solution while the open‐chain azido form dominates in acidic solution. In addition it has been shown that the presence of a phenyl group in a position adjacent to the tetrazole nucleus apparently stabilizes the tetrazole ring.
Quinoline syntheses by reaction of hydrazoic acid with α,β‐disubstituted cis‐chalcones
Authors: Pratt Robert E. , Welstead William J. , Lutz Robert E.
Published: March 2009

Hydrazoic‐sulfuric acid mixture converted cis‐α‐phenyl‐β‐benzoylchalcone (trans‐dibenzoylstilbene, 4) into 2,3‐diphenyl‐4‐benzoylquinoline (5) the structure of which was proved by debenzoylation to 2,3‐diphenylquinoline. α,β‐Diphenyl and cis‐α,β‐dibromochalcones similarly were converted respectively into 2,3,4‐triphenylquinoline (19) and 2‐phenyl‐3,4‐dibromoquinoline (20). The structure of 19 was shown by difference from the corresponding isoquinoline 21 (synthesized). Smith's mechanism for the analogous conversion of o‐phenylbenzophenone into 9‐phenylphenanthridine through the 9‐fluorenol and the 9‐hydroazide with loss of nitrogen and ring expansion, was supported by methyl label experiments using 2‐(p‐tolyl)benzophenone which gave a 53:47 mixture of 3‐ and 8‐methyl‐6‐phenylphenanthridines. Applicability of the mechanism to the reactions with disubstituted cis‐chalcones was shown by sulfuric acid conversions of two of these into indenol 22 and 2‐bromo‐3‐phenylindenone (24), respectively. trans‐Dibenzoylstilbene underwent resinification in sulfuric acid, giving the quinoline (5) only when hydrazoic acid was present.
Synthesis of 4‐hydroxy‐2‐methylisocarbostyril‐3‐carboxanilides
Authors: Lombardino Joseph G.
Published: March 2009

A procedure for preparing the title compounds is reported. These compounds represent the first 2‐substituted‐4‐hydroxyisocarbostyrils, a structural type which could not be obtained by N‐alkylation of the previously known 2H‐4‐hydroxyisocarbostyril. Although 3‐carboxanilides in this series could not be made by aminolysis of the corresponding 3‐ester, they were successfully prepared from 4‐hydroxy‐2‐methylisocarbostyril using aryl isocyanates and sodium hydride in hexamethylphosphoramide as solvent. Evidence is presented for an enolic (“4‐hydroxy”) form of the title compounds and preference for O‐alkylation was observed. Contrary to previous reports, data was obtained to support the enolic structure of the previously known 4‐hydroxyisocarbostyril.
The reactions of 4‐dicyanomethylene‐2‐phenyl‐4H‐1‐benzopyran and some benzologs with nucleophiles
Authors: Reynolds G. A. , Vanallan J. A. , Petropoulos C. C.
Published: March 2009

4‐Dicyanomethylene‐2‐phenyl‐4H‐1‐benzopyran (1) reacts with primary amines under mild conditions to give 4‐imino‐3‐alkyl‐5‐alkylimino‐2‐phenyl‐3,4‐dihydro‐5H‐[1]benzopyrano[3,4‐c]‐pyridine derivatives which, in turn, are hydrolyzed with acid to 4‐imino‐3‐alkyl‐2‐phenyl‐3,4‐dihydro‐5H‐[1]benzopyrano[3,4‐c]pyridin‐5‐ones. When more vigorous conditions are employed for the reactions of 1 with primary amines, Dimroth rearrangements take place and the products are derivatives of 4‐alkyl‐ (or aryl)amino‐5‐alkyl‐ (or aryl)imino‐2‐phenyl‐5H‐[1]benzopyrano‐[3,4‐c]pyridine. The latter compounds are hydrolyzed by acid to the corresponding 5‐pyridone derivatives. The reaction of 1 with piperidine gives 2‐phenyl‐4‐piperidyl‐5H‐[1]benzopyrano‐[3,4‐c]pyridin‐5‐one. Sodium methoxide reacts with 1 to give 3‐cyano‐2‐methoxy‐4‐(2‐hydroxyphenyl)‐6‐phenylpyridine. Two benzologs of 1 have been allowed to react with primary and secondary amines and the products are analogous to those obtained from 1.
Synthesis of 3,5‐Disubstituted‐4,5‐dihydroindeno[1,2‐c] [1,2]diazepin‐6(1H)‐ones
Authors: Mosher William A. , Innes John E.
Published: March 2009

3,5‐Disubstituted 4,5‐dihydroindeno[1,2‐c][1,2]diazepin‐6 (1H)‐ones (3a–g) were obtained in 29–72% yields by condensing 2‐(substituted‐2‐acylethyl)‐1,3‐indandiones (1a–n) with hydrazine. The NH group of the indenodiazepinones 3a–g is quite unreactive. Two methods based on the Michael reaction were used for preparing the acylethylindandiones 1a–n: one from 1,3‐indandione and chalcone‐type compounds and the other from 2‐benzylidene‐1,3‐indandione and acetophenones. The latter method was found more practical and of more general application.
Cyanorhodanines
Authors: Allan Frederick J. , Allan G. Graham
Published: March 2009

Three types of cyanorhodanines have been synthesized for evaluation as fungicides for the protection of cellulose. The first group comprised five cyanobenzylidenerhodanines prepared by the condensation of 4‐cyanobenzaldehyde with rhodanine and its 3‐allyl, ‐carboxymethyl, ‐ethyl and ‐phenyl congeners. The corresponding carboxy analogs were similarly synthesized from terephthaldehydic acid. The second group consisted of cyanobenzylidenerhodanines containing a β‐cyanovinyl aromatic side‐chain introduced by the condensation of ethyl cyanoacetate with formylbenzylidenerhodanines. The latter are versatile intermediates for the synthesis of substituted rhodanines and a convenient procedure for their preparation is now reported. The third type of cyanorhodanines contained a β,β‐dicyanovinyl aromatic side‐chain correspondingly prepared from the formylbenzylidenerhodanines by condensation with malononitrile.
Pyrrolemethanols
Authors: Sonnet Philip E.
Published: March 2009

Both 2‐ and 3‐pyrrolemethanols hearing electron‐withdrawing ring substituants react with alcohols in the presence, of acid to produce ethers. Dipyrrylmethanes are formed only as byproducts under these conditions. Other reactions of these pyrrolemethanols are described.
Bis‐Pyrazolones as azodienophiles
Authors: Gillis Bernard T. , Valentour James C.
Published: March 2009

Lead tetraacetate oxidations of 2,3,3a,4,6,7,7a,8‐octahydrobenzo[1,2‐c:4,5‐c']dipyrazolo‐3,7‐dione and 2,3,3a,4,5,5a,6,7‐octahydrobenzo[2,1‐c:3,4‐c']dipyrazolo‐3,6‐dione in the presence of 1,3‐cyclopentadiene, 1,3‐cyclohexadiene, 2,3‐dimethyl‐1,3‐butadiene or 1,4‐diphenyl‐1,3‐butadiene have yielded octahydrodipyridazino[1,2‐a:1,2‐a']benzo[1,2‐c:4,5‐c']dipyrazolo‐6,14‐diones and octahydrodipyridazino[1,2‐a:1,2‐a']benzo[2,1‐c:3,4‐c']dipyrazolo‐6,9‐diones. In one of the eight Diels‐Alder reactions two isomeric products were isolated.
The synthesis of 3,4,4a,9a‐tetrahydro‐2(1H)‐carbazolones
Authors: Wittekind Raymond R. , Lazarus Sam
Published: March 2009

Cyclization of 4‐(1‐methylindol‐3‐yl)‐2‐butanone and the corresponding 1‐benzyl analog in trifluoroacetic acid furnishes 9‐methyl‐ and 9‐benzyl‐3,4,4a,9a‐tetrahydro‐2(1H)‐carbazolone, respectively. Under the same conditions, 4‐(indol‐3‐yl)‐2‐butanone gives the dimer, 3‐(3‐oxo‐butyl)‐2‐[3‐(3‐oxobutyl)‐2‐indolinyl] indole. When boron trifluoride etherate is used instead of trifluoroacetic acid, the desired 3,4,4a,9a‐tetrahydro‐2(1H)‐carbazolone is obtained. The determination of the structure of the tetrahydrocarbazolones is described and the stereochemistry of the ring fusion is discussed.
Nitrene insertion reactions. 1. Dimethyl N‐carbethoxyazepines and their cycloaddition reaction products
Authors: Photis James M.
Published: March 2009

Dimethyl‐N‐carbethoxyazepines, isolated from the reaction between ethyl azidoformate and o‐, m‐ and p‐xylenes, react with tetracyanoethylene to give [4 + 2] Diels‐Alder adducts. Nitroso‐benzene is inert toward 2‐methylazepines, but reacts with 3,6‐dimethyl‐N‐carbethoxyazepine to give a [6 + 2] cycloadduct. The effect of two methyl substituents on the course of the cycloaddition reactions is discussed.
Synthesis of heterocyclic compounds. II. A simple one‐step synthesis of pyridines from aldehydes and malononitrile
Authors: Alvarez‐Insúa Alberto S. , Lora‐Tamayo M. , Soto José L.
Published: March 2009

The condensation of several aldehydes with malononitrile in the presence of a alcohol‐alkoxide system provides a new simple, one‐step route to 4‐substituted 2‐amino‐3,5‐dieyano‐6‐alkoxy‐pyridines. The best results are obtained with the aromatic aldehydes. The structure of these compounds was established from a study of their infrared, ultraviolet and nuclear magnetic resonance spectra.
Reaction of phenolic mannich bases with enamines. General synthesis of pyran‐containing fused ring systems
Authors: Von Strandtmann Maximilian , Cohen Marvin P. , Shavel John
Published: March 2009

The reaction of o‐phenolic Mannich bases with enamines yields cyclic O,N‐acetals having a 2‐aminodihydropyran or a spiropyranopiperidine structure in common. The 2‐aminodihydro‐pyrans are easily converted to 2‐hydroxydihydropyrans and to pyrans. The preparation of a large variety of pyran‐containing fused ring systems is reported.
Thiophene series. Substituent effect on thiophenoxy debromination of various 2‐nitro‐3‐bromo‐5‐X‐thiophenes
Authors: Guanti Giuseppe , Dell'Erba Carlo , Spinelli Domenico
Published: March 2009

The kinetics of the reaction of a series of 2‐nitro‐3‐bromo‐5‐X‐thiophenes with sodium thiophenoxide in methanol were determined.

The plot of log k against σ‐values gave ρ‐value + 4.51 at 20°.

Good correlation was observed pointing out the validity of the Hammett relationship for reactions occurring directly on the thiophene ring at the β‐position with respect to the heteroatom.
Rearrangements of the aminoalkylation products of tetrahydro‐2H‐1,3‐oxazine‐2‐thione
Authors: Clapp Richard C. , Long Louis
Published: March 2009

The nature of the compounds afforded by the rearrangement of the aminopropylation and aminoethylation products of tetrahydro‐2H‐1,3‐oxazine‐2‐thione (I) has been investigated. In both instances compounds that can be considered to result from ring opening at either the C‐O or C‐S bond of a hypothetical bicyclic intermediate of structure IV were obtained. The compounds required for identification of the rearrangement products have been prepared by the reaction of the 2‐methylthio derivatives of 2‐thiazoline, 5,6‐dihydro‐4H‐1,3‐thiazine, and 5,6‐dihydro‐4H‐1,3‐oxazine with the appropriate hydroxyalkylamine or mercaptoalkylamine.
Benzothiazolium derivatives. III. Nucleophilic substitution reactions of benzothiazolium salts
Authors: Sohar Paul , Denny George H. , Babson Robert D.
Published: March 2009

The reactions of 2,3‐dihydrothiazolo[2,3‐b]benzothiazolium bromide 1 (A− Br−) with certain nucleophilic reagents have been performed for the purpose of ascertaining the reaction pathways and identifying the group that is displaced from the central carbon atom of the dithiocarbamate system. The nature of complex salt‐like intermediates formed initially from 1 (A− Br−) has been studied and confirmed. For comparison, a number of nucleophilic substitution reactions of 2‐methylthio‐3‐methylbenzothiazolium iodide 17 and 2‐dimethylamino‐3‐methylbenzothiazolium perchlorate 18 have been examined.
Luminescent 2‐(hydroxyaryl)‐1 H‐naphth[2,3‐d] imidazole derivatives
Authors: Orlando C. M. , Wirth J. G. , Heath D. R.
Published: March 2009

The synthesis and spectroscopic properties of a new class of luminescent 1H‐naphth[2,3‐d]‐imidazole compounds are described. The ultraviolet spectra of 2‐(hydroxyaryl)‐1H‐naphth[2,3‐d]‐imidazole derivatives are presented and discussed. Significant effects of structure and physical state of the luminescent compounds are observed on the measured emission wave length throughout the visible spectrum. The luminescence quantum efficiency of one of the naphthimidazole derivatives is reported.
Pyridazines. XXXVIII. Pyrrolo[1,2‐b] pyridazines and 4H‐4a,7b‐diazacyclopent[cd] indenes
Authors: Zupan M. , Stanovnik B. , Tišler M.
Published: March 2009

Pyrrolo[1,2‐b] pyridazines have been prepared and investigated for electrophilic substitutions. Depending on the electrophile and reaction conditions, mono, di, tri or tetrasubstituted derivatives were formed. Some investigations are reported also for the related 4H‐4a,7b‐diazacyclopent[cd]‐indenes.
Azinotriazines. I. Synthesis and spectral data of pyrido[3,2‐e] ‐as‐triazines
Authors: Lewis Arthur , Shepherd Robert G.
Published: March 2009

A series of pyrido[3,2‐e]‐as‐triazines (VI) was prepared via acid‐catalyzed cyclization of suitable 2‐substituted 3‐aminopyridines obtained by reduction of the corresponding 3‐nitro‐pyridines. Cyclization of 3‐amino‐2‐hydrazinopyridines (III) with triethyl orthoformate and hydrochloric acid, or cyclodehydration of 2‐(2‐acetylhydrazino)‐3‐aminopyridines (IV) with alcoholic hydrogen chloride gave 1,2‐dihydropyrido[3,2‐e]‐as‐triazine hydrochloride (V). Mild dehydrogenation with alkaline potassium ferricyanide yielded heteroaromatic pyrido[3,2‐e]‐as‐triazines (VI), for which ultraviolet and nmr spectral data are reported.
Azinotriazines. II Cyclizations leading to pyrido[3,4‐e] ‐ and [4,3‐e]‐as‐triazines. Ring interconversion of a pyrido‐as‐triazine 1‐oxide to a pyridotriazole
Authors: Lewis Arthur , Shepherd Robert G.
Published: March 2009

Treatment of 4‐chloro‐3‐nitropyridine (I) with hydrazine hydrate followed by catalytic reduction gave 3‐amino‐4‐hydrazinopyridine (III). Acid‐catalyzed cyclizations of III and subsequent dehydrogenation gave pyrido[3,4‐e]‐as‐triazines (V). Treatment of I with guanidine followed by base‐catalyzed cyclization gave 3‐aminopyrido[4,3‐e]‐as‐triazine 1‐oxide (VII). The 1‐oxide function was removed by reduction and subsequent dehydrogenation gave the 3‐amino derivative (IX). On treatment with hot alkali VII rearranged to a triazolo[4,5‐c]pyridine (X). The ultraviolet and nmr spectra of derivatives of the title ring systems are reported.
Nitro derivatives of phenyl‐1,2,3‐triazole
Authors: Neuman Peter N.
Published: March 2009

A number of tri‐ and tetranitro‐N‐phenyl‐1,2,3‐triazolyl compounds were synthesized by a combination of condensation, cycloaddition, and nitration reactions, and their crystal densities, impact sensitivities, and thermal stabilities were determined.
Sur la synthèse des furo[3,2‐c] pyridines
Authors: Eloy F. , Deryckere A.
Published: March 2009

Le principe de la cyclisation des isocyanates de vinyle, substitués par un groupement vinylidène appartenant à un hétérocycle, a été appliqué à la synthèse de furo[3,2‐c] pyridines. La cyclisation thermique de furyl‐2 isocyanato‐1 éthylénes a conduit à des furo[3,2‐c]pyridones qui furent utilisées comme intermédiates pour l'obtention d'autres dérivés furopyridiniques.
Derivatives of 10,11‐dihydro‐5H‐dibenzo[a,d] cycloheptene and related compounds. III. Azaketones
Authors: Villani Frank J. , Daniels Peter J. L. , Ellis Claire A. , Mann Thomas A. , Wang Kai‐Chih
Published: March 2009

The preparation and properties of four isomeric azadibenzoeycloheptenones 3 and their 10,11‐dihydro derivatives 2 are described. The ketones 2 were prepared by cyclization of appropriately substituted phenethylpyridine carboxylic acids and dehydrogenated to 3. Four monochloro derivatives 24 of the 4‐azaketone 2d are also described.
Hydrogen bonded complexes of ϵ‐caprolactam
Authors: Wigler Paul W. , Vercellotti Sharon V.
Published: March 2009

The ultraviolet absorption band of a complex between 9‐ethyladenine and ∈‐caprolactam has been observed at a wavelength longer than that of the absorption band for the 9‐ethyladenine monomer. Absorbance values (at 277.5 mμ) of solutions that contained 9‐ethyladenine and different concentrations of ∈‐caprolactam in cyclohexane were determined at different temperatures. Linear plots were utilized to determine the apparent association constant (K′ ) of the 9‐ethyladenine‐caprolactam complex over the range of 25° to 60°. The K′ values for the complex of 4‐aminopyrimidine and ∈‐caprolactam were determined for the same temperature range from the absorbance of cyclohexane solutions at 282.5 mμ. The K' values of the two complexes are the same at 25°, but ∈‐caprolactam is more strongly bonded to 9‐ethyladenine than to 4‐aminopyrimidine at elevated temperatures. The synthesis of 4‐amino‐1‐ethylbenzimidazole hydro‐chloride was performed. An attempt to detect a complex between ∈‐caprolactam and 4‐amino‐1‐ethylbenzimidazole in a cyclohexane solution was not successful.
An unusual arylation of 4‐oxo‐3,4‐dihydropyrimido[4,5‐b]quinoline
Authors: Campaigne E. , Randau G.
Published: March 2009

Treatment of 4‐oxo‐3,4‐dihydropyrimido[4,5‐6 ]quinoline (II) with phosphorus oxychloride and a dialkylaniline resulted in the introduction of a p‐dialkylaminophenyl group at position‐5, and reduction of the central (pyridine) ring, as well as substitution of oxygen by chlorine at po‐sition‐4, forming compounds considered to be 4‐chloro‐5‐(p‐dialkylaminophenyl)‐5, 10‐dihydro‐pyrimido[4,5‐6 ]quinolines (XV). Several 4‐oxo‐3,4‐dihydropyrimido[4,5‐b ]quinolines having phenyl substituents at position‐5 were synthesized unequivocally, and could be readily reduced to the corresponding 4‐oxo‐5‐phenyl‐3,4,5,10‐tetrahydropyrimido[4,5‐6]quinolines, and the 4‐oxo group replaced by chlorine, in the usual manner, leading to compounds related structurally to XV. Comparison of the chemical and physical properties of these compounds established the structure of XV, and a mechanism which rationalizes the formation of XV from II is presented.
The synthesis of oxazolo‐ and oxazino[3,2‐d] [1,4]benzodiazepinones
Authors: Lemke Thomas L. , Hanze Arthur R.
Published: March 2009

Cyclization of 2′‐benzoyl‐4′‐chloro‐2‐[(2‐hydroxypropyl)amino]acetanilide (8) and 2′‐bcnzoyl‐4‐ehloro‐2‐[(3‐hydroxypropyl)amino]acetanilide (7) led to the respective oxazolo (3) and oxazino (5) analogs of 7‐chloro‐1,3‐dihydro‐5‐phenyl‐2H‐1,4‐benzodiazepin‐2‐one. Cyclization of 2′‐benzoyl‐4′‐chloro‐2‐[2,3‐dihydroxypropyl)amino]acetanilide (9) could produce either the oxazolo (4) or oxazino (10) analog. Data is presented to show that cyclization occurred to give the oxazolo (4) analog.
Novel buron heterocycles. I. 2,3‐dihydro‐1,3,2‐benzodiazaborin‐4(III)‐ones and 1,2‐dihydro‐ 1,3,2‐benzodiazaborines
Authors: Yale Harry L.
Published: March 2009

A series of 2,3‐dihydro‐1,3,2‐benzodiazaborin‐4(IH)‐ones have been prepared and their ir spectra compared with those of their carbon isosteres. Solvolysis of these boron compounds in ethanol has been followed by uv and reveals a relationship between structure and rates of ethanol‐ysis. Unexpectedly, these boron heterocycles, in contrast to their carbon isosteres, dissolve in aqueous alkali to form stable anions and the significance of this is discussed. The 1 :1 adducts of 1 and phosphorus oxychloride has been utilized to prepare two derivatives of the very stable 1,2‐dihydro‐2‐phenyl‐1,3,2‐benzodiazaborin heterocycle.
Investigation of routes to indeno[2,1‐f] ‐2H‐1,2,4‐triazepinediones
Authors: Mosher William A. , Foothill Richard H.
Published: March 2009

The synthesis of a number of 3‐(substituted thiosemiearbazido)‐2‐(a]koxycarbonyl)indones (1) from 2‐alkoxycarbonyl‐1, 3‐indandiones and substituted thiosemicarbazides is described. Cyeliza‐tion of compounds 1 in the presence of a variety of catalysts gave substituted Δ2‐1,2,4‐triazoline‐5‐thiones (3) and (4), instead of the expected substituted 3(4H)‐thioxoindeno[2,1‐f]‐2H‐1,2,4‐triazepine‐5(5aH),6‐diones (2). The preparation of 4‐(2‐methyl‐1,3‐dioxo‐2‐indanylmethyl)semi‐carbazide (9) is reported. Cyelization of 9 gave 5,5a‐dihydro‐5a‐methylindeno[2,1‐f]‐2H‐1,2,4‐triazepine‐3(4H),6‐dione (10). Structure assignments of these compounds are discussed.
Small charged rings. XIV. Dimer formation through 2‐arylaziridinium salts
Authors: Leonard Nelson J. , Klainer Jeremy A.
Published: March 2009

2,5‐Diary 1‐substituted N,N,.N',N' ‐lelramethylpiperazinium diperchlorates have been synthesized in two steps: condensation of an aromatic aldehyde with dimethylamine perchlorate to give the corresponding N,N‐dimelhylaralkylideneiminium perehlorate, followed by reaction with diazo‐methane. Nmr evidence was obtained for the intermediate in the second step being the corresponding 2‐aryl‐1, 1‐dimethylaziridinium perchlorate.
The synthesis of 3‐deazaorotidine and related nucleoside derivatives of 4‐hydroxy‐2‐pyridone
Authors: Currie Bruce L. , Robins Morris J. , Robins Roland K.
Published: March 2009

Condensation of 6‐earbethoxy‐4‐hydroxy‐2‐pyridone or a silyl derivative of 5‐earbomethoxy‐4‐hydroxy‐2‐pyridone with 2′,3′,5′‐tri‐O‐benzoyl‐D‐ribofuranosyl halide has provided the 3‐deaza analogs of orotidine and uridine‐5‐carboxylic acid. The corresponding amides have also been prepared in view of their possible structural relationship to l‐β‐D‐ribohiranosyl nicotinamide. Tri‐O‐benzoyl‐3‐deazauridine was treated with N‐bromosuccinimide to give, after deblocking, 3‐bromo‐4‐hydroxy‐1‐(β‐D‐ribofuranosyl)‐2‐pyridone. The anomeric configuration of these nuclcosides was confirmed by pmr spectroscopy.
Substitution and addition reactions of aziridine with perfluorinated hydrocarbons. Nuclear magnetic resonance spectra of N‐perfluoroalkyl aziridines
Authors: Lautenschlaeger F. , Myhre M. , Hopton F.
Published: March 2009

The reaction of aziridine with chlorotrifluoroethylene, perfluorobenzene, cyclic perfluoroole‐fins and tetracyanoethylene was investigated. The degree of substitution was affected by the ring size of the perfluoroolefin.

The temperature dependence of the nuclear magnetic resonance spectra, particularly with respect to the temperature of coalescence of the aziridinyl protons, was investigated.
The crystal and molecular structure of |2‐keto‐|7‐deoxo‐8‐azacstrone methyl ether hydrohromide
Authors: Brown J. N. , Towns R. L. R. , Trefonas L. M.
Published: March 2009

The crystal and molecular structure of 12‐keto‐17‐deoxo‐8‐azaeslrone methyl ether hydro‐bromide (C18H24BrNO2) has been determined by a single crystal, x‐ray diffraction study. The compound crystallizes in the monoclinie space group P21/n with unit cell constants a = 12.024 (2), b = 10.340 (1), c = 14.269 Å (2), β = 104.12° (1). The structure was solved by the heavy atom method and refined by block‐diagonal least‐squares to a final R‐value = 0.036 for the 8.35 independently measured, statistically significant reflections. All hydrogen atoms, including methyl hydrogens, were located.
Total synthesis of camptotheein. I. Synthesis of ethyl 8‐(α‐chlorobutyryloxymethyl)‐7,9‐dioxo‐7,8,9,11 ‐tetrahydroindolizino[ 1,2‐a]quinoline‐8‐carboxylate and related tetracyclic compounds
Authors: Liao T. K. , Nyberg Wayne H. , Cheng C. C.
Published: March 2009

A practical synthesis of the 8‐ethoxycarlbonyl‐8‐hydroxymethyl‐7,9‐dioxo‐7,8,9,11‐tetrahydro‐indolizino[ 1,2‐a]quinoline ester of α‐chlorohutyric acid, a tetracyclic intermediate for the total synthesis of the alkaloid camptothecin, was prepared from the anil of o‐aminohenzaldehyde in six steps. Preparative procedures of other related tetracyclic compounds are also reported.
Mass spectra of pyridazines and their N‐oxides
Authors: Ogura Haruo , Sugimoto Shingo , Igeta Hiroshi , Tsuchiya Takashi
Published: March 2009

The mass spectra of pyridazines and their N‐oxides is reported. Previous electron impact studies on aromatic amine N‐oxides reported the appearance of M‐16 and/or M‐17 ion peaks as the usual feature of the fragmentations. In our experiments, the representative fragmentation of the pyridazine N‐oxides involves formation of a M‐30 (M‐NO) ion. The fragmentation patterns substantiated by extensive high resolution studies and the analysis of the appropriate metastable ions.
Synthesis of new s‐triazolo[4,3‐b] pyridazines
Authors: Francavilla P. , Lauria F.
Published: March 2009

A new synthesis of s‐triazolo[4,3‐b]pyridazine derivatives has been achieved starting from 3,6‐dichloropyridazine. The method opens the way to substitutions in the 2‐ or 3‐ positions. A tri‐cycloderivative, a bis‐s‐triazolopyridazine, has also been synthesized.
Conformational isomerism of 2‐carboazetidines
Authors: Rodebaugh Richard M. , Cromwell Norman H.
Published: March 2009

A number of 1‐alkyl‐2‐carboazetidines have been prepared from the reaction of primary amines with α,γ‐dibromocarbonyl compounds. Several of these new azetidines exhibit doublet carbonyl stretching absorptions in their infrared spectra. A possible explanation of this phenomenon is offered in terms of three rotational conformers which represent various degrees of dipole‐dipole and steric interactions. The cis and trans forms of 1‐t‐butyl‐2‐carbomethoxy‐4‐methylazetidine have been obtained from the reaction of t‐butylamine with methyl α,γ‐dibromovalerate. A detailed examination indicates that the ir and nmr spectra of these epimers are in agreement with the foregoing conformational postulates.
Azomethines with electron withdrawing substituents II. 1,4‐Cycloaddition of sulfonyl or acyl isonitrosomalono compounds with cyclopentadiene
Authors: Biehler Jean‐Marie , Fleury Jean‐Pierre
Published: March 2009

Le caractère diénophile dcs dérivés isonitrosomaloniques sulfonylés ou acylés dépend étroite‐ment des substituants du carbone (‐CN, ‐COOR, ‐CONH2) et de l'azote (‐O‐SO2‐R, ‐O‐CO‐R) azométhiniques. Les azométhines à substituants nitrile et sulfonyloxy présentent l'activité diénophile la plus marquée. La structure des adduits aza‐2 norbornènes obtenus avec le cyclopentadiène a été déterminée par spectrométrie de R.M.N. La cycloaddition est stéréo‐sélective; les facteurs intervenant dans la transition sont discutés. Selon leur substitution en position 2 ou 3 les aza‐2 norbornenes subissent une scission rétrodienique plus ou moins aisée.
Ring closures from enecarbamoyl thiocyanates. Syntheses of 5,6,7,8‐tetrahydro‐4‐thio‐2,4(lH,3H)‐quinazolinediones and related compounds
Authors: Chupp John P.
Published: March 2009

Alkyl (1‐cyclohexen‐1‐yl)carbamoyl chlorides (1) react with thiocyanate ion to form enecarbamoyl thiocyanates (2). In pyridine solution 2 readily isomerizes to the isothiocyanate 4, which however is not isolated, but immediately transformed in good yields to tetrahydro‐4‐thio‐2,4(lH,3H)quinazolinediones (3). Various transformations of 3, including conversion to tetra‐hydro‐2,4(2H,4H)quinazolinedione (5), dithione (6), alkylation products (8 and 9), sodium salts 11 and Raney nickel degradation to 4,4a,5,6,7,8,8a‐octahydro‐l‐methyl‐2(1H)quinazolinone (7), were carried out to investigate their chemistry and substantiate structural assignments.
Isothiazolcs III: 2‐carbamoyl‐4‐isothiazolin‐3‐ones
Authors: Lewis Sheldon N. , Miller George A. , Szamborski Eugene C. , Hausman M.
Published: March 2009

The reaction of several 3‐hydroxyisothiazoles with alkyl and aryl isocyanates has given high yields of 2‐earbamoyl‐4‐isothiazolin‐3‐ones as the only isolahle products. Reaction with an iso‐thioeyanate, however, afforded a mixture of the isomerie 2‐thioearbamoyl‐4‐isothiazolin‐3‐one and 3‐isothiazolyl thiocarbamate.
1,3,5‐Trisubstituted hexahydrotriazines as mannich reagents. II. Preparation of p‐secondary aminomethylphenols
Authors: Reynolds Delbert D. , Cossar Bernard C.
Published: March 2009

Phenol and a variety of substituted phenols have been aminomethylated by new Mannich reagents prepared from 1,3,5‐trisubstituted hexahydrotriazines. In contrast to the conventional aminomethylating agents, which react preferentially in the ortho position, the new reagents favor para substitution. A variety of newpara secondary aminomethylphenols have been prepared.
The crystal structure of 2‐hydroxymethylpyridine N‐oxide
Authors: Desiderata R. , Terry J. C.
Published: March 2009

The structure of 2‐hydroxymethylpyridine N‐oxide was determined from X‐ray diffractometer data by a direct method. The compound crystallizes in the monoclinic space group P21/c with cell dimensions a = 7.079, b = 8.046, c = 10.599 Å, cosβ = −0.2252. A total of 1241 independent reflections were refined to an R value of 0.06. The N‐O dative bond has a length of 1.321 Å and the dative oxygen is bonded to a hydroxyl group on a symmetry related molecule by an inter‐molecular hydrogen bond. The structure corroborates recent findings concerning the relationship between the strength of hydrogen bonding to a dative oxygen and the length of the NO dative bond.
Studies on the synthesis of anthyridine
Authors: Carboni S. , Da Settimo A. , Hertini D. , Mori C. , Tonetti I.
Published: March 2009

The sulfuration of various anthyridones (I) to the corresponding thioderivatives (II) and the desulfuration of these to 5,10‐dihydroanthyridine (III) is descrihed. The preparation of anthyridin‐5‐one (1d) from 6 ‐methyl‐2,2 ‐dipyridylamino‐3‐carboxylic acid (V) is also described.
The preparation of 3‐chlorobenzo[b] thiophene derivatives from cinnamie acids
Authors: Wright W. B. , Brabander H. J.
Published: March 2009

The reaction of cinnamic acid derivatives with thionyl chloride and pyridine is a general procedure for the preparation of derivatives of 3‐chlorobenzo[b] thiophene‐2‐carbonyl chloride from readily accessible starting materials. These compounds are easily converted to the corresponding acids, esters and amines.
7‐Deazapurines II. Syntheses and reactions of 5‐aminopyrrolo[2,3‐d] pyrimidine‐6‐carbonitrile and related compounds
Authors: Kim Dong Han , Santilli Arthur A.
Published: March 2009

The reaction of 4‐chloro‐2‐phenyl‐5‐pyrimidinecarbonitrile (III) with N‐methylglycinonitrile gave 4‐[(eyanomethyl)methylamino]‐2‐phenyl‐5‐pyrimidinecarbonitrile (VIa), which upon cycli‐zation under Dieckmann conditions afforded 5‐amino‐7‐methyl‐2‐phenyl‐7H‐pyrrolo[2,3‐d]‐pyrimidine‐6‐carbonitrile (VIIa). Other examples (VIIb and VIIc) were prepared similarly from the reactions of III with glycinamide and ethyl glycinate, respectively. The preparation of simple 5‐amino derivatives of the pyrrolo[2,3‐d] pyrimidines thus synthesized is described. The alkyla‐tion of VIIc with N‐cyeloheptylchloroacetamide took place at the ring nitrogen, giving XII. The reaction of VIIa with formamide gave 4‐amino‐5‐methyl‐7‐phenyl‐5H‐pyrrolo[2,3‐d:4,5‐d′ ]‐dipyrimidine (XIII), the first member of a new ring system. Treatment of VIIa with carbon disulfide and pyridine afforded another example of this new ring system, 1,5‐dihydro‐5‐methyl‐7‐phenyl‐2H‐pyrrolo[2,3‐d:4,5‐d′] dipyrimidine‐2,4‐(3H)dithione (XIV).
Nitrene insertion reactions. Part III. The steric effect of the Isopropyl and t‐butyl groups. 1,6 Type cycloaddition of tetracyanoethylene to 1H‐azepines
Authors: Photis James M.
Published: March 2009

Various alkyl and aryl carboxynitrenes generated thermally from the azidoformates react with para‐di‐t‐butylbenzene with a high degree of selectivity to yield predominantly, or exclusively, 3,6‐di‐t‐butylazepine‐N‐carboxylates. 3,6‐Dialkylazepines react readily with tetracyanoethylene to afford the first known TCNR‐1H‐azepine cycloadducts of the 1,6 type.
Synthesis of furo[2,3‐b]pyridine
Authors: Mcfarland J. W. , Wollerman R. P. , Sadler W. C. , Coleman G. N.
Published: March 2009

Two routes were employed to synthesize unsubstituted furo[2,3‐b]pyridine (IV). The first method started with ethyl 5‐aminofuro[2,3‐b] pyridine‐2‐carboxylate (1) and involved successive deamination, hydrolysis, and decarboxylation. The second method began with 5‐nitrofuro[2,3‐b ]‐pyridine‐2‐carboxylic acid (V) and consisted of successive decarboxylation, reduction, and deamination reactions.
2,2′‐Disubstituted 5,5′‐bipyrimidines
Authors: Pater Richard
Published: March 2009

Syntheses of 2,2′‐bis(methylthio)‐, 2,2′‐diamino‐, 2,2′‐dihydroxy‐, 2,2′ ‐dichloro‐, and 2,2′ ‐diethoxy‐5,5;′‐bipyrimidines are described.
Syntheses of benzomorphan and related compounds. Part III. An alternate synthesis of 3‐substituted‐1,2,3,4,5,6‐hexahydro‐8‐hydroxy‐2,6‐methano‐6,11‐dimethyl‐3‐benzazocine
Authors: Kametani T. , Kigasawa K. , Hayasaka M. , Wakisaka K. , Satoh F. , Aoyama T. , Ishimaru H.
Published: March 2009

Reduction of the appropriate Schiff bases gave 5‐benzylamino‐3‐methyl‐2‐pentene (XVII) and l‐benzylamino‐3‐methylpentane (XVIII), the condensation of which with methyl 3‐(4‐methoxyphenyl)‐2,3‐epoxypropionate afforded a mixture of the isomeric 1‐benzyl‐2‐(4‐methoxy‐benzyl)‐3,4‐dimethyl‐4‐hydroxypiperidines (XIXa and XIXb). The piperidinols were heated with hydrobromic acid, respectively, to afford 3‐benzyl‐1,2,3,4,5,6‐hexahydro‐8‐hydroxy‐2,6‐methano‐6,11‐dimethyl‐3‐benzazocine (II). Since the conversion of II to pentazocine (Ic) had already been accomplished, an alternate synthesis of Ic was achieved.
Mass spectra of some 1,2,4‐triazole derivatives
Authors: Potts K. T. , Armbruster R. , Houghton E.
Published: March 2009

Fragmentation of various 1,2,4‐triazole derivatives occurs by two predominant pathways involving the loss of RCN originating from both C3 and C5 positions. The resulting diazirinium radical cation was observed to lose a nitrogen atom to give a nitrilium ion whose substitution pattern was dependent upon the original substituents in the nucleus.
The synthesis of some 7‐ and 7,8‐substituted 2,3,4,5‐tetrahydro‐1H‐3‐benzazepines
Authors: Pecherer B. , Sunbury R. C. , Brossi A.
Published: March 2009

The nitration of 2,3,4,5‐tetrahydro‐1H‐3‐benzazepine and its 3‐methyl and 3‐acetyl derivatives yields the corresponding 7‐nitro derivatives which can be further transformed by classical procedures. The preparation of the ether cleavage products of the known 2,3,4,5‐tetrahydro‐7,8‐dimethoxy‐1H‐3‐benzazepine is also reported.
Synthesis of two new heterocyclic ring systems: Benzo[3,4] cyclohepta[1,2‐d]‐pyrimidines and benzo[3,4]cyclohepta[2,1‐d] pyrimidines
Authors: Rosowsky Andre , Chen Katherine K. N. , Lin May , Nadel Marilyn E. , Amand Richard St. , Yeager Sandra A.
Published: March 2009

Three 2,4‐diamino‐l(), 11‐dihydro‐9H‐benzo[3,4]cyclohepta[ 1,2‐d]pyrimidines (6a‐6c) representing the first examples of a new ring system were synthesized from 2‐benzosuberones and cyanoguanidine. Similarly, 2,4‐diamino‐6,7‐dihydro‐5H‐benzo[3,4]cyelohepta[2,1‐d]pyrimidine (24) was prepared from 1‐benzosuberone. The ultraviolet spectral properties of these compounds were examined with reference to those of the analogs in which the central ring is five‐ and six‐mernbered.
Reactions of some pyranylidene esters with amines
Authors: Van Allan J. A. , Reynolds G. A.
Published: March 2009

The reactions of 4‐(2,2‐dimethyl‐4,6‐dioxo‐1,3‐dioxan‐5‐ylidene)‐2,6‐diphenyl‐4H‐pyran (1) with primary amines gave the corresponding 1‐substituted 1,4‐dihydropyridine derivatives. The related benzo derivative of 1 (12) and primary amines gave 3‐substituted 3,4‐dihydro‐2‐phenyl‐5H‐[1]benzopyrano[3,4‐c] pyridine‐4,5‐dione derivatives. With secondary amines, 12 gave 2‐phenyl‐4H,5H‐pyrano[3,4‐c] [1]benzopyrane‐4,5‐dione, and with isopropylamine, N,N‐dimethylhydra‐zine, and methanolic potassium hydroxide, 12 gave 4‐phenacylcoumarin. Some reaction intermediates were isolated which indicate probable reaction paths. The reactions with amines were extended to a naphtho derivative of 1 (19) and to a thia homolog of 12 (24).
Synthesis of amino‐5‐arylsulfonylpyrimidines
Authors: Santilli Arthur A. , Rosenberg Murray D. , Osdene T. S. , Childress Scott J.
Published: March 2009

Several new 4‐amino‐5‐arylsulfonylpyrimidines were prepared via the reaction of various α‐(ethoxymethylene)arylsulfonylacetonitriles with guanidine or variously substituted amidines (Table II). 2,4‐Diamino‐5‐(p‐chlorophenylsulfonyl)pyrimidine (IIIg), a typical example, was prepared from the reaction of 2‐(p‐chlorophenylsulfonyl)‐3‐ethoxyacrylonitrile (IId) with guanidine in refluxing ethanol containing sodium ethoxide. With proper substitution of the ethoxymethylene intermediate, the method was found suitable for the preparation of other compounds having either a hydroxy or methyl group at the 4‐position of the 5‐arylsulfonylpyrimidine. The fluoro group in 2,4‐diamino‐5‐(p‐fluorophenylsulfonyl)pyrimidine (IIIx) was successfully replaced by nucleophilic reagents such as sodium ethoxide, N‐methylpiperazine and N,N‐diethylethylene‐diamine. Attempts at direct displacement of fluorine by ammonia at 190° were unsuccessful.
Enol‐keto tautomerism of alkyl 2‐picolyl ketones
Authors: Wursthorn Karl R. , Sund Eldon H.
Published: March 2009

An analysis of the ir and nmr spectra taken on a series of nine different alkyl 2‐picolyl ketones clearly indicates that there is an enol‐keto tautomerism. The enol:keto ratio exhibits a marked dependence on both solvent polarity and the nature of the alkyl group. The equilibrium values correlate with the Taft sleric substituent constants.
Organosilicon compounds XV. Cleavage of the silicon‐carbon bond of 2‐trimethylsilyl‐1‐methylimidazole and 2‐trimethylsilyl‐1‐methylbenzimidazole
Authors: Pinkerton Frank H. , Thames Shelby F.
Published: March 2009

Cleavage of the aryl‐silicon bond of 2‐trimethylsilyl‐1‐methylimidazole (Ia) and 2‐trimethylsilyl‐1‐methylbenzimidazole (Ib) has been effected by five carbonyl reagents, i.e. aldehydes, acid halides, chloroformates, anhydrides and isocyanates, to provide a novel synthetic route to a host of functionally substituted heterocycles. Compound Ia reacted exothermically at room temperature, with four of the, five carbonyl reagents.
Pyrimidine N‐oxides. Preparation of 6‐chloro‐2,4‐diaminopyrimidine 3‐N‐oxide and its reactions
Authors: Delia Thomas J. , Venton Duane L.
Published: March 2009

The peroxyacid oxidation of 6‐chloro‐2,4‐diaminopyrimidine (1) led to two products, 6‐chloro‐2,4‐diaminopyrimidine 3‐N‐oxide (2) and 2,4‐diamino‐5,6‐dichloropyrimidine 3‐N‐oxide (3). The assignment of structure of both of these compounds was made on the basis of ir, uv, nmr, and mass spectral data. A discussion of the pathways involved in the formation of 3 is presented.
On the mechanism of the 1,2‐cycloaddition reaction of ketenimines and nitrosoarenes
Authors: Barker Marvin W. , Combs Leon L. , Gill Jack T.
Published: March 2009

The 1,2‐cycloaddition of nitrosoarenes to ketenimines producing 3‐iminosubstituted‐1,2‐oxazetidines has been found to proceed more rapidly if photosensitized conditions are employed. This data plus the specificity of the reaction allows for a reasonable postulation of the non‐photochemical room temperature reaction.
Cycloaddition reactions of some analogs of the acridizinium ion
Authors: Bradsher C. K. , Frazer M. G. , Burnham W. S.
Published: March 2009

The 1‐aryl‐2‐imidazo[1,2‐b]isoquinolin‐4‐ium system (3 and 4), prepared by the action of aniline, or a suitable aniline derivative upon 2‐phenacyl‐3‐chloroisoquinolinium bromide undergoes cycloaddition reactions only with the more nucleophilic alkenes such as cyclopentadiene or 9‐vinylcarbazole.

The pyrazino[1,2‐b]isoquinolin‐5‐ium‐2‐oxide (8–10) system reacts with nucleophilic alkenes more readily than does the acridizinium system 1. For both systems the cycloaddition appears to occur across the meso position of the central ring.
Mass spectrometric investigation of isomeric 1,2,3,4‐tetrahydro‐4‐oxoquinazolines
Authors: Bogentoft Conny , Danielsson Bengt
Published: March 2009

Six isomeric methylphenyl‐1,2,3,4‐tetrahydro‐4‐oxoquinazolines have been prepared and their fragmentation patterns upon electron impact studied. Deuterium labelling and high‐resolution measurements were performed in order to facilitate the interpretation of the spectra. The dissociation of the molecular ion follows two main routes, the fragmentation being governed by the position of the phenyl group.
Fluorescence and liquid scintillation properties of 1,3,4‐oxadiazoles. I. Excimer formation in 2‐alkyl‐5‐(4‐biphenylyl)‐1,3,4‐oxadiazoles
Authors: Taber Richard L. , Binkley Edward S.
Published: March 2009

Several 2‐alkyl‐5‐(4‐biphenylyl)‐1,3,4‐oxadiazoles have been synthesized and investigated as primary liquid scintillation solutes and are found to be excellent fluors. Fluorescence studies at varying concentrations and temperatures indicate that excimer formation is possible at high concentration and low temperatures.
Mesoionic compounds VIII. Synthesis of 3‐phenylsydnonyl substituted alkenes. Some new photochromic sydnones
Authors: Greco Claude V. , O'Reilly Bernard P.
Published: March 2009

The reactions of 3‐phenylsydnonyllithium with a variety of ketones to afford tertiary carbinols 4a‐4i and their subsequent dehydration to 4‐(3‐phenylsydnonyl) alkenes 5a‐5i are discussed. Among the alkenes, 2‐[4‐(3‐phenylsydnonyl)]propene (5b) and 1‐[4‐(3‐phenylsydnonyl)]‐1‐cyclohexene (5i) were photochromic. A Wittig reaction between ethyl‐4‐(3‐phenylsydnonyl)‐ketone and methylenetriphenylphosphorane afforded the photochromic 2‐[4‐(3‐phenylsydnon‐yl)]‐1‐butene(5j).
O‐ and N‐substituted products from the treatment of 3,5‐dichioro‐2‐pyridone with benzenesulfonyl chlorides
Authors: Hamer Martin , Lira E. Patrick
Published: March 2009

Treatment of 3,5‐dichloro‐2‐pyridone with various benzenesulfonyl chlorides in the presence of triethylamine at 25° yielded both O‐ and N‐sulfonylated products. These isomers were isolable, relatively stable compounds which were distinguished by their ir and uv spectra.
2,1‐benzisothiazoline 2,2‐dioxide. I. Some 3‐substituted derivatives
Authors: Skorcz Joseph A. , Suh John T.
Published: March 2009

A number of 3‐mono‐ and 3,3‐disubstituted derivatives of 1‐methyl 2,1‐benzisothiazoline 2,2‐dioxide (IIa), a unique benzosultam, were synthesized. Starting materials for the condensation and aminoalkylation reactions utilized were IIa and the 3‐methyl compound IIb, which were prepared by cyclization of the 2′‐chloro‐N‐methylalkylsulfonanilides, Ia and b, respectively.
The preparation of 3,5‐disubstituted tetrahydro‐4H‐1,3,5‐oxadiazine‐4‐thiones, tetrahydro‐4H‐1,3,5‐thiadiazin‐4‐ones, and tetrahydro‐4H‐1,3,5‐thiadiazine‐4‐thiones
Authors: Seidel Michael C. , Boettner Fred E.
Published: March 2009

The reaction of 1,3‐disubstituted thioureas with formaldehyde under acidic conditions with removal of water yielded 3,5‐disubstituted tetrahydro‐4H‐1,3,5‐oxadiazine‐4‐thiones. When hydrogen sulfide was bubbled through the reaction mixture, the corresponding tetrahydro‐4H‐1,3,5‐thiadiazine‐4‐thiones were formed. Similarly, starting from 1,3‐disubstituted ureas, a number of tetrahydro‐4H‐1,3,5‐thiadiazine‐4‐ones were prepared. The latter compounds were also oxidized to the corresponding sulfoxides and sulfones.
1H‐pyrazolo[3,4‐b]pyridines
Authors: Höhn H. , Denzel Th. , Janssen W.
Published: March 2009

The synthesis of a number of new 1H‐pyrazolo[3,4‐b]pyridine‐5‐carboxylic acid derivatives is described. Most of these compounds have either an alkoxy or a basic substituent in position 4.
Quinazolines. VII. Synthesis of 1,3‐Diamino‐5,6‐dihydrobenzo[f]quinazolines
Authors: Rosowsky Andre , Chen Katherine K. N. , Papathanasopoulos Nickolas , Modest Edward J.
Published: March 2009

Eighteen new 1,3‐diamino‐5,6‐dihydrobenzo[f] quinazolines (6, R. = alkyl, Cl, MeO) were synthesized via the condensation of appropriate 2‐tetralones with cyanoguanidine under fusion conditions. Methods were developed for the preparation of a number of heretofore undescribed 2‐tetralones as precursors. The final products can be viewed as conformationally rigid analogs of pyrimethamine (2), and are of interest as inhibitors of dihydrofolate reductase and as potential antimalarial and antitumor agents.
Quinazolines. VIII. Synthesis of 1,3‐diaminobenzo[f]quinazolines
Authors: Rosowsky Andre , Chen Katherine K. N. , Nadel Marilyn E. , Papathanasopoulos Nicholas , Modest Edward J.
Published: March 2009

Twenty‐one 1,3‐diaminobenzo[f]quinazolines (2, R = H, alkyl, halogen, methoxy) were synthesized as planar tricyclic analogs of the antimalarial agent pyrimethamine (1). The synthetic methods included i) condensation of 1‐cyano‐2‐naphthylamines with cyanamide in the presence of pyridine hydrochloride, ii) cyclization of N1,N5‐bis(2‐naphthyl)biguanide hydrochlorides in diphenyl ether at 250°, iii) reaction of 2‐naphthylamine hydrochlorides with excess sodium dicyanamide in boiling 1‐octanol, and iv) selenium dioxide dehydrogenation of 1,3‐diamino‐5,6‐dihydrobenzo[f]quinazolines. A number of new 2‐naphthols and 2‐naphthylamines were synthesized as intermediates. Substituent effects on the ultraviolet absorption spectra of 1,3‐diamino‐benzo[f]quinazolines were investigated and found to be additive. These compounds are of interest as inhibitors of dihydrofolate reductase and as potential antimalarial and antitumor agents.
Tautomerism of 2‐amino‐2‐oxazolin‐4‐ones. II
Authors: Rapi G. , Ginanneschi M. , Belgodere E. , Chelli M.
Published: March 2009

The study of the tautomerism of 2‐amino‐2‐oxazolin‐4‐one (1) and its methyl derivatives has been completed. The methylation of 1 gave 2‐imino‐3‐methyloxazolidin‐4‐one (4) and 2‐methyl‐amino‐2‐oxazolin‐4‐one (7). All attempts to isolate O‐methyl derivatives failed. The uv, nmr, ir, and Raman spectra led to the definite conclusion, in agreement with the chemical evidence, that the 2‐aminooxazolinic form a, if it is theoretically possible, predominates in all compounds investigated. Otherwise the 2‐iminooxazolidinic form b predominates. The assignment of the carbonyl stretching is discussed on the basis of ir and Raman data. The nmr spectrum of compound 7 shows anomalous behaviour, most probably due to the existence of a monomer‐dimer equilibrium.