bluuebunny/crossref_metadata_2025 huggingface dataset:
Heterocycles. 9. 2‐Aryl‐2H‐1,4‐tetrahydrooxazines
Authors: Meyer Donald R. , Weintraub Philip M.
Published: March 2009

Reaction of 2‐bromo‐1‐phenylethanones with diethanolamine gave 2‐hydroxymorpholines. Acetylation gave mono or diacetates. Acid catalyzed dehydrations gave several types of products whose structures are discussed.
The crystal structures of 10‐oxa‐1,4,7‐trithiacyclododecane, 7,10,13‐trioxa‐1,4‐dithiacyclopentadecane, 7,10,13,16‐tetraoxa‐1,4‐dithiacyclooctadecane and 4,7,13,16‐tetraoxa‐1,10‐dithiacyclooctadecane
Authors: Dalley N. Kent , Larson Steven B. , Smith Judith S. , Matheson K. Lee , Izatt Reed M. , Christensen James J.
Published: March 2009

The structures of four macrocyclic polyether sulfides have been determined by single crystal x‐ray diffraction methods. The compounds studied were 1,4,7‐trithia‐12‐crown‐4, 1,4‐dithia‐15‐crown‐5, 1,4‐dithia‐18‐crown‐6 and 1,10‐dithia‐18‐crown‐6. In all four compounds the potential donor sulfur atoms point out of the ring. This causes the rings to be irregularly shaped.
Synthesis of cis‐ and trans‐1,3‐dicarbomethoxy‐2‐aminoisoindoline
Authors: Sanaa Paolo , Savelli Francesco , Cignarella Giorgio
Published: March 2009

The title compounds (4a,b) were synthesized starting with dimethyl α,α'‐dibromo‐o‐benzenediacetate and t‐butyl carbazate. Alternate approaches to 4 involving reduction of the appropriate 2‐nitrosoisoindoline were found unsuitable because of predominant side reactions.
Chemistry of the phenoxathiins and isosterically related heterocycles. XVI. The synthesis and molecular structure of 3‐azaphenoxathiin: Evidence in support of factors responsible for control of the dihedral angle
Authors: Caldwell Steven R. , Martin Gary E. , Simonsen Stanley H. , Inners Ruth R. , Willcott M. Robert
Published: March 2009

The synthesis of the 3‐azaphenoxathiin ring system and its molecular structure are reported. Based on 13C‐nmr chemical shift additivities associated with the insertion of an annular nitrogen atom and the observed 13C‐nmr shift of Cα, the title compound was predicted to have a dihedral angle θ = 160.2°. The observed dihedral angle from the crystal structure was found to be θ = 167.07° which is in reasonably good agreement with the predicted value. It is proposed that the position of the annular nitrogen atom is solely in‐control of the observed dihedral angle.
Novel heterocycles. 7. Reaction of 2‐chloronicotinonitrile with thioureas. Synthesis of the pyrido[2,3‐d]pyrimido‐[2,1‐b][1,3]thiazine ring system
Authors: Coppola Gary M. , Shapiro Michael J.
Published: March 2009

N,N'‐Dimethylthiourea and 3,4,5,6‐tetrahydro‐2‐pyrimidinethiol were allowed to react with 2‐chloro‐nicotinonitrile (1) and their products investigated by standard methods and by carbon‐13 nmr. In both instances, displacement of the chlorine occurred by nitrogen not the sulfur of the thioureas. Secondary cyclizations occurred by attack of nitrogen on the nitrile to furnish 3a, and by sulfur on the nitrile to give 4b, a new ring system. Tricyclic 4b was hydrolyzed in dilute acid to give 5, or alkylated with methyl iodide in the presence of sodium hydride to give the ring opened product 6.
Synthesis and antihypertensive properties of a novel series of 3‐substituted amino‐s‐triazolo[3,4‐α]phthalazine derivatives
Authors: Omar A.‐Mohsen M. E. , Kasem M. Gabr , Laabota I. M. , Bourdais J.
Published: March 2009

A novel series of 3‐substituted amino‐s‐triazolo[3,4‐a]phthalazine derivatives has been synthesized by the one‐pot cyclodesulfurization reactions utilizing 1‐hydrazinophthalazine, alkyl, aryl, or aralkylisothiocyanates and dicyclohexylcarbodiimide (DCCD) mixtures. The products did not exhibit any antihypertensive properties. Their pmr and mass spectral analysis is given.
Synthesis of pyrrolo[2,3‐b]azepine‐4,7‐dione derivatives
Authors: Vora Manhar M. , Yi C. S. , Blanton C. Dewitt
Published: March 2009

The Dieckmann reaction has been successfully applied for the first time in the synthesis of pvrrolo[2,3‐b)]azepines.
Reaction of 4‐chloro‐3‐nitrocoumarin with glycine and alanine, and the synthesis of 1‐benzopyrano[3,2‐c]pyrimidine‐3,5‐dione
Authors: Stunić Z. , Trkovnik M. , Laćan M. , Janković R.
Published: March 2009

A considerable improvement of the yields obtained in substitution of halogens in 4‐chloro‐3‐nitrocoumarin by amino acid or amino acid ester residues was achieved over literature claims. Electrochemical reduction of the nitro group in these products brought about a ring closure leading to benzopyranopyrimidinones, which are obtained in excellent yields.
Synthesis of 4‐β‐D‐arabinofuranosyl‐5,6‐dihydro‐2H‐1,2,4‐thiadiazin‐3‐one 1,1‐dioxide and x‐ray diffraction analysis of its 2′,3‐anhydro precursor
Authors: Schroeder A. C. , Srikrishnan T. , Parthasarathy R. , Block A.
Published: March 2009

Reaction of 2‐amino‐3′,5′‐bis(O‐tert‐butyldimethylsilyl)‐β‐D‐arabinofuran[1′,2′:4,5]‐2‐oxazoline with 2‐chloroethylsulfonyl chloride in the presence of sodium bicarbonate followed by removal of the protecting groups gave 2′,3‐anhydro‐4‐β‐D‐arabinofuranosyl‐5,6‐dihydro‐2H‐1,2,4‐thiadiazin‐3‐one 1,1‐dioxide (5), which by treatment with ammonia was converted to 4‐β‐D‐arabinofuranosyl‐5,6‐dihydro‐2H‐1,2,4‐thiadiazin‐3‐one 1,1‐dioxide (6). The structure of compound 5 was unequivocally established by means of an x‐ray diffraction analysis. The compound crystallized in the space group P212121 with unit cell dimensions a = 5.883(3), b = 9.352(2), c = 18.769(7) Å, Z = 4. Its structure was established by direct multisolution techniques and refined by the full matrix least squares method to a final R value of 0.058 for the 1515 reflections observed.
Pyrimidinylalkylthiols, furo[2,3‐d]pyrimidines and derivatives
Authors: Furukawa Sunao , Takada Mitsutaka , Castle Raymond N.
Published: March 2009

Several pyrimidinylalkylthiols and furo[2,3‐d]pyrimidines and their derivatives have been prepared as potential radiation‐protection agents.
Synthesis via pummerer intermediates. IV. Synthesis of 1‐(4‐hydroxy‐2‐oxo‐2H‐1‐benzopyran‐3‐yl)pyridinium hydroxide inner salt derivatives and 3‐(2H)benzofuranones by the action of phosgene in pyridine on 2‐hydroxy‐1‐[(methylsulfinyl)acetyl]benzene derivatives
Authors: Connor David T. , Sorenson Roderick J.
Published: March 2009

The treatment of ketosulfoxide 1 with phosgene in pyridine gave a mixture of 1‐(4‐hydroxy‐8‐methoxy‐2‐oxo‐2H‐1‐benzopyran‐3‐yl)pyridinium hydroxide inner salt (4) and 7‐methoxy‐2‐(methylthio)‐3‐(2H)benzofuranone (7). Ketosulfoxides 8 and 11 behaved similarly. The inner salt structure assigned to compounds 4, 10, and 13 was confirmed by the unambiguous synthesis of 10 and 13 from hydroxycoumarins 15 and 18.
The synthesis of pyridine derivatives from 3‐formylchromone
Authors: Haas Georges , Stanton James L. , Von Sprecher Andreas , Wenk Paul
Published: March 2009

3‐Formylchromone (1) reacts with active methylene derivatives to yield condensation products2a‐d, 10,11and12. Treatment of2a‐dwith ammonia or methylamine gives pyridines3–6. Alternatively, reaction of1with enamine derivatives yields pyrido compounds15, 17, 19, 21, 23and28in one step. Factors determining the formation and regiospecificity of the pyridine ring forming reactions are also discussed.
Carboxylation and acylation of 4,7‐dimethoxyindoles and a study of the corresponding dealkylated derivatives
Authors: Malesani Giorgio , Chiarelotto Gianfranco , Ferlin Maria Grazia , Masiero Sergio
Published: March 2009

Treatment of 4,7‐dimethoxyindoles 1 and 9 with ethylmagnesium bromide and ethyl chloroformate in refluxing dry ether gives the corresponding indole‐1‐carboxylic acid ethyl esters 3 and 10 as major products, together, with minor amounts of indole‐3‐carboxylic acid ethyl esters 2 and 11. Similar treatment of 4,7‐dimethoxyindole (1) with ethylmagnesium bromide and chloroacetyl chloride affords the related 3‐chloroacetyl derivative 13. All of the new 4,7‐dimethoxyindole compounds were dealkylated with anhydrous aluminium chloride in refluxing dry benzene. Transformation of these demethylated indoles into other interesting derivatives, in view of possible antimicrobial activity is also reported.
The synthesis of heteroaromatic nitro compounds from 3‐nitrochromone
Authors: Haas Georges , Stanton James L. , Winkler Tammo
Published: March 2009

3‐Nitrochromone (1) reacts with a series of nucleophiles by Michael addition followed by intramolecular condensation to yield pyrrolyl (2), phenyl (3), pyridyl (4), pyrido (5,6), pyrimidyl (7) and pyrazolyl (8) nitro derivatives. The reactions proceed under basic catalysis in 39–78% yields. Conversion of 4 to 3,4‐dihydrobenzofuro[3,2‐b]quinol‐1‐(2H)one (12) is also described. Carbon‐13 data for 2, 5, 6 and 8 are discussed. The one bond C,H coupling constants in the nitropyridines are also reported and used as an analytical tool.
Anticonvulsant activity and succinate dehydrogenase inhibitory property of new substituted thiobarbiturates
Authors: Dhasmana Anjali , Barthwal J. P. , Pandey B. R. , Ali B. , Bhargava K. P. , Parmar S. S.
Published: March 2009

Eight 1‐aryl‐3‐(2‐pyridyl)thiobarbiturates were synthesized and evaluated for their anticonvulsant property and their ability to inhibit succinate dehydrogenase activity of rat brain homogenates. These substituted thiobarbiturates (100 mg./kg., i.p.) provided 20–60% protection against pentylenetetrazol‐induced convulsions in albino mice. Low toxicity of these compounds was reflected by their high approximate LD50values which were found to range from 500–1000 mg./kg. All substituted thiobarbiturates (ImM) inhibitedin vitrosuccinate dehydrogenase activity and the degree of inhibition ranged from 10–72%.
Synthesis of 3‐formyltetronic acid and enamine derivatives
Authors: Gelin Suzanne , Chantegrel Bernard
Published: March 2009

The first reported synthesis of 3‐formyltetronic acid and its conversion to enamine derivatives is described. 3‐Dimethylaminomethylene‐2,4‐dioxotetrahydrofuran derivatives were also prepared by treatment of tetronic acids with dimethylformamide diethyl acetal. Nmr spectral studies are included.
Tetronic acids and derivatives. Part XI . Structure of coupling products of tetronic acids with benzenediazonium sulfate
Authors: Gelin Suzanne , Pollet Patrick
Published: March 2009

13C Nmr, 1H nmr and ir parameters of coupling products of tetronic acids (4‐hydroxy‐5H‐furan‐2‐ones) with benzene diazonium sulfate are only consistent with a phenylhydrazone formulation with an almost equal ratio of the syn and anti configurations. These results contrast with those of coupling products of acyclic 3‐ketoesters, existing mainly as anti tautomers, and more sharply with the 3‐parabromophenylhydrazone of L‐dehydro ascorbic acid, which is exclusively syn.
Mononuclear heterocyclic rearrangement. Part 6 . Studies on base catalysis of the rearrangement of the (Z)‐p‐nitrophenylhydrazone of 3‐benzoyl‐5‐phenyl‐1,2,4‐oxadiazole in benzene: Effect of piperidine, triethylamine and of some secondary amines
Authors: Frenna Vincenzo , Vivona NicolÒ , Spinelli Domenico , Consiglio Giovanni
Published: March 2009

The kinetics of the title reaction catalyzed by various secondary and tertiary amines have been measured at 40° in benzene. The catalysis laws which were observed confirm the previous hypothesis about the mechanism of the mononuclear heterocyclic rearrangements.
Free‐radical reactions of diazonium salts with α,β‐unsaturated carbonyl compounds. A new synthesis of 1,4‐diarylpyrazole derivatives
Authors: Citterio Attilio , Ramperti Massimo , Vismara Elena
Published: March 2009

Free‐radical decomposition of diazonium salts catalyzed by titanous or titanous and ferrous salts in the presence of β‐substituted α,β‐unsaturated carbonyl compounds leads to 1,4‐diarylpyrazole derivatives. The reaction occurs via an intermediate azo compound (1), which can be reduced by the metal salt or can be isolated and hydrogenated to pyrazole derivatives.
Novel heterocycles. 8. Fused isoquinolines derived from the reaction of homophthalic anhydride with cyclic imino ethers
Authors: Coppola Gary M.
Published: March 2009

Homophthalic anhydride and cyclic imino ethers react to produce fused isoquinolines 6–9. In the case of 2‐ethoxy‐2‐oxazoline, a second compound whose structure is believed to be the spiro compound 10 was also isolated. Spectral data for these type systems are discussed.
Synthesis of 5‐ethynylorotic acid
Authors: Bhatt Ram S. , Kundu Nitya G. , Chwang T. Ling , Heidelberger Charles
Published: March 2009

Condensation of 2,4‐dimethoxy‐5‐iodo‐6‐carbomethoxypyrimidine (10) with copper (I) 3‐tetrahydropyranyloxyprop‐1‐ynide (4) afforded 2,4‐dimethoxy‐5‐(3′‐tetrahydropyranyloxyprop‐1′‐yn)‐6‐carbomethoxypyrimidine (11), which was hydrolyzed to produce 2,4‐dimethoxy‐5‐(3′‐hydroxyprop‐1′‐yn)‐6‐carbomethoxypyrimidine (12). Oxidation of 12 with dimethyl sulfoxide‐oxalyl chloride reagent gave the acetylenic aldehyde (13), which on treatment with sodium methoxide in dry tetrahydrofuran yielded 2,4‐dimethoxy‐5‐ethynyl‐6‐carbomethoxypyrimidine (14). The trimethylsilyl derivative (15) was deprotected by sequential treatment with iodotrimethylsilane and aqueous sodium hydroxide, leading to the formation of 5‐ethynylorotic acid (1).
Pipérazinediones‐2,5. 2. Les acides dioxothiazolidino pipérazine carboxyliques et leurs dérivés désulfurés
Authors: Jerumanis Stanislas , Lemieux Alain
Published: March 2009

Les auteurs ont synthétisé l'acide N‐t‐butoxycarbonylglycyl‐3 méthoxycarbonyl‐4 diméthyl‐5,5 thiazolidine carboxylique‐2 (5) à partir de trois différents produits de départ (Schéma 1). Ce produit 5 at été transformé en diméthyl‐2,2 dioxo‐5,8 thiazolidino[3,2‐a]pipérazine carboxylate‐3 de méthyle (7) puis hydrolysé en acide cor‐respondant 8 avec un rendement quantitatif. Par désulfuration réductrice, le produit 8 ainsi que son isomère, le diméthyl‐1,1, dioxo‐5,8 thiazolidino[3,4‐a]pipérazine carboxylate‐3 de butyle (10) ont été transformés en nouveaux dérivés de la pipérazinedione‐2,5, soit l'acide(dioxo‐2,5 pipérazinyl)‐2 isobutyrique (9) et l'(isopropyl‐2 dioxo‐3,6 pipérazinyl‐1) acétate de butyle (11). Les données spectroscopiques sont conformes aux structures des produits obtenus.
Reactions of 2‐chloro‐2‐(4‐pyridyl)propane with nucleophiles. Substitution on tertiary carbon
Authors: Feuer Henry , Doty James K. , Kornblum Nathan
Published: March 2009

The reaction of 2‐chloro‐2‐(4‐pyridyl)propane (2) with lithium 2‐propanenitronate affords the C‐alkylation product 2‐nitro‐3‐(4‐pyridyl)‐2,3‐dimethylbutane (3), the Michael‐adduct 2‐nitro‐2‐methyl‐4‐(4‐pyridyl)pentane (4), 4‐isopropenylpyridine (5) and 2‐(4‐pyridyl)‐2‐propanol (6). Of these four products, only the formation of 3 is suppressed when the reaction is performed in the presence of radical inhibitors. The reaction of compound 2 with sodium azide gives the tertiary substitution product 2‐azido‐2‐(4‐pyridyl)propane (8). The reaction is not influenced by radical inhibitors. This is also the case in the reaction of 2 with sodium benzenethiolate, which affords 2‐mercaptophenyl‐2‐(4‐pyridyl)propane (9) and 1‐mercaptophenyl‐2‐(4‐pyridyl)propane (10). Compound 5, the product of an E2‐type elimination is also formed in the azide and thiolate reactions. A Michael type addition of sodium benzenethiolate to 5 explains the formation of 10. Similarly, generation of 5 in reactions of 2 with sodium methanethiolate and sodium cyanide accounts for the formation of 1‐mercaptomethyl‐2‐(4‐pyridyl)propane (11) and 3‐(4‐pridyl)butanenitrile (12), respectively.
Dilithiation of 1‐benzenesulfonylindoles
Authors: Sundberg Richard J. , Broome Rita , Walters Claudia Powers , Schnur Dora
Published: March 2009

Benzenesulfonylindole is converted to a dilithio derivative by 2.2 equivalents of lithiating reagent. The dilithio derivative gives rise to sultones on reaction with carbonyl compounds. This reaction proceeds by an intramolecular displacement of the indole group from the bis‐adduct. Fair to poor yields of the 2‐indolycarbinols can also be isolated. Benzoyl chloride forms a thiazine dioxide ring by addition at both the 2‐indolyl and 2′‐phenylsulfonyl positions. 3‐Methyl‐1‐benzenesulfonylindole is also easily dilithiated.
Synthesis of 2,3‐dihydrospiro[benzofuran‐2,4′ ‐piperidines] and 2,3‐dihydrospiro[benzofuran‐2,3′‐pyrrolidines]
Authors: Effland Richard C. , Gardner Beth Ann , Strupczewski Joseph
Published: March 2009

The synthesis of 2,3‐dihydrospiro[benzofuran‐2,4′‐piperidines] 3 and 2,3‐dihydrospiro[benzofuran‐2,3′]‐pyrrolidine] 6 is described. The synthesis was achieved by a Grignard reaction of a 2‐fluorobenzylhalide with an appropriate cycloazaalkyl ketone to yield the tertiary alcohols 1 and 4. Subsequent intramolecular displacement of the aromatic fluoride by the derived alkoxides provided the novel system.

Nitration of 1′‐acetyl‐2,3‐dihydrospiro[benzofuran‐2,4′‐piperidine] 7 resulted in a 5‐nitro derivative.
Heterocyclic systems. II. Synthesis of 4H,6H‐pyrrolo[1,2‐a][4,1]benzoxazepine
Authors: Massa Silvio , Corelli Federico , Stefancich Giorgio
Published: March 2009

The reduction of 1‐(2‐methoxycarbonylphenyl)pyrrole‐2‐carboxaldehyde by lithium aluminum hydride led to 1‐(2‐hydroxymethylphenyl)‐2‐hydroxymethylpyrrole, which was in turn transformed into 4H,6H‐pyrrolo‐[1,2‐a][4,1]benzoxazepine through intramolecular dehydration. The reductive action of sodium borohydride, instead, allowed the preparation of 6‐oxo‐4H‐pyrrolo[1,2‐a][4,1]benzoxazepine.
A short synthesis of 5‐methylhistamine
Authors: Pfister Jürg R. , Kurz Walter , Harrison Ian T.
Published: March 2009

Methoxybromination of 4,5‐dihydro‐2‐methylfuran (4), followed by treatment of the resulting bromoketal 5 with hot formamide, gave 4‐(2‐hydroxyethyl)‐5‐methyl‐1H‐imidazole (3) in 25% yield. This method provides easy access to the selective H2‐agonist 4‐methylhistamine (1) via the chloromethyl intermediate 2.
Notes on the synthesis of meso‐substituted porphyrins from pyrryl carbinols and the mechanism of the rothemund reaction
Authors: Little Robert G.
Published: March 2009

Aryl pyrryl carbinols have been found to readily cyclize to meso‐substituted tetraarylporphyrins in yields which are consistent with the intermediacy of the pyrryl carbinols in the Rothemund reaction. Acidic solutions of the pyrryl carbinols show absorption bands characteristic of pyrrolylmethenes. It is suggested that pyrrolylmethenes are likely intermediates in the Rothemund reaction.
Novel heterocycles. 9. Synthesis of the benzofuro[2,3‐c][1,2]thiazine ring system
Authors: Coppola Gary M.
Published: March 2009

The treatment of 2‐coumaranone with the Vilsmeier reagent affords three products: 2‐chloro‐3‐benzofurancarboxaldehyde (3), 3‐dimethylaminomethylene‐2‐(3H)benzofuranone (4), and 3‐dimethylaminomethylene‐2,3‐dihydro‐2‐oxo‐6‐benzofurancarboxaldehyde (5). Both 4 and 5 are isolated as a mixture of E and Z isomers. The reaction of 3 with the anion of N‐methylmethanesulfonamide affords the title compound 1‐methyl‐1H‐benzofuro[2,3‐c][1,2]‐thiazine 2,2‐dioxide (6). Spectral data is also discussed.
1‐Azidoisochromenes. A new route to 3,1‐benzoxazepines
Authors: Le Roux Jean‐Pierre , Desbene Paul‐Louis , Cherton Jean‐Claude
Published: March 2009

Nucleophilic attack of sodium azide on isochromylium salts leads to the preparation of 1‐azidoisochromenes which when heated lose molecular nitrogen and give 3–1‐benzoxazepines.
Synthesis of nitrooxazoles
Authors: Hammar W. James , Rustad Mark A.
Published: March 2009

A reaction sequence involving halogenation and replacement of the halo substituent by a nitro group using dinitrogen tetraoxide has led to a general, convenient route to 5‐nitrooxazoles. Reaction schemes employing both bromine and iodine as the halo substituent have been investigated; however, the method using iodine preceded by a mercuration step affords a better overall yield in the range of 20–50%. Both 2‐ and 4‐nitro‐oxazoles can be prepared by this latter sequence, though in lower overall yields (4–12%).
The synthesis of 2‐chloromethylpyridine from 2‐picoline‐N‐oxide
Authors: Ash Mary Lynne , Pews R. Garth
Published: March 2009

Phosphoryl chloride reacts with 2‐picoline‐N‐oxide in the presence of triethylamine to give 2‐chloromethylpyridine in 90% conversion with 98% selectivity. Diethylchlorophosphate, ethyl chloroformate, chloroacetyl chloride and phosgene also react with 2‐picoline‐N‐oxide to give 2‐chloromethylpyridine in moderate yields. Other potential chlorinating agents, titanium tetrachloride, zinc chloride, magnesium chloride and sulfuryl chloride, did not convert 2‐picoline N‐oxide into 2‐chloromethylpyridine.
Synthesis of naphthyridinone derivatives as potential antimalarials
Authors: Carroll F. Ivy , Berrang Bertold D. , Linn C. Preston
Published: March 2009

In this paper we present the synthesis of 8‐(4′‐amino‐1′methyl‐butylamino)‐5‐(β,β,β‐trifluoroethoxy)‐1,6‐naphthyridine (4), 8‐(4′‐amino‐1′methylbutylamino)‐6‐methyl‐1,6‐naphthyricline‐5‐one (5), two 1‐alkyl‐3‐(4′‐amino‐1′‐methylbutylamino)‐7‐methyl‐1,8‐naphthyridin‐4‐ones (20a) and 20b), 3‐(1′‐amino‐4′‐methylbutyl‐amino)‐l‐ethyl‐7‐methyl‐l,8‐naphthyridin‐4‐one (20c), and 4‐(4′‐diethylamino‐1′‐methylbutylamino)‐7‐methyl‐1,7‐naphthyridin‐8‐one (28). The compounds were evaluated for antimalarial activity in the Plasmodium berghei screen and found to be inactive.
Synthesis of pyreno[b]thiophenes
Authors: Pratap Ram , Tominaga Yoshinori , Lee Milton L. , Castle Raymond N.
Published: March 2009

The synthesis of all the isomers of pyreno[b]thiophene namely, pyreno[1,2‐b]thiophene, pyreno[2,1‐b]thiophene and pyreno[4,5‐b]thiophene is described. Their spectral characteristics are also discussed.
Synthesis of phenaleno[1,9‐bc]thiophene
Authors: Tominaga Yoshinori , Lee Milton L. , Castle Raymond N.
Published: March 2009

The cyclization of 2‐acetonylthionaphthalene, prepared from 2‐mercaptonaphthalene (1) and chloro‐acetone in the presence of sodium hydroxide, with polyphosphoric acid gave 1‐methylnaphtho[2,1‐b]thiophene (4) in 64% overall yield from 1. By bromination with N‐bromosuccinimide, 4 was converted in 40% yield into l‐bromomethylnaphtho[2,1‐b]thiophene (8). Treatment of 8 with potassium cyanide in a phase‐transfer medium gave l‐cyanomethylnaphtho[2,1‐b]thiophene (10) in good yield. Compound 10 was reduced to the corresponding aldehyde 11 and then cyclized with polyphosphoric acid to phenaleno[l,9‐bc]thiophene (12) in 24% overall yield from 10.
Some anomalous reactions of 4‐quinolone‐5‐diazonium salts
Authors: Frank Judit , Rákóczy Piroska , Radics Lajos , Gács‐Baitz Eszter
Published: March 2009

Diazotisation of the 5‐amino function in 6,7‐alkoxy‐l‐ethyl‐l,4‐dihydro‐4‐oxoquinoline‐3‐carboxylic acids led to various products. Dediazoniation was always accompanied by fission of the 6‐alkoxy substituent; 6,7‐methylenedioxy groups gave formaldehyde which could form a m‐dioxino ring. Hydrolysis of the diazonium chlorides resulted in halo‐dediazoniation.
Some heterocyclic sulfonyl chlorides and derivatives
Authors: Cremlyn Richard J. , Swinbourne Fred J. , Yung Kin‐Man
Published: March 2009

The syntheses of 4‐ and 5‐chlorosulfonylfuran‐2‐carboxylic acid (Ia,IIa), 4‐chlorosulfonylfuran‐2‐carboxamide (Ib), 3,5‐dimethylpyrazole and isoxazole‐4‐sulfonyl chlorides (IIIa,IVa) and 2,4‐dimethylthiazole‐5‐sulfonyl chloride (Va) are described. The sulfonyl chlorides were converted into a range of amides, hydrazides and azides. Condensation of the sulfonohydrazides with β‐dicarbonyl compounds, gave the corresponding β‐ketohydrazones (VII), which, with the exception of the derivatives (VIIe,f,g,i), were converted to the sulfonylpyrazoles (VIII). The structures and spectral data of these compounds are briefly discussed. The reaction of the sodio derivative of acetylacetone with thiophene‐2‐sulfonyl chloride (VIc) gave 3‐(thiophene‐2‐sulfonyl)pentane‐2,4‐dione (XII), which with hydrazine gave 4‐(thiophene‐2‐sulfonyl)‐3,5‐dimethylpyrazole (XIII). However, the analogous reaction with thiophene‐2‐sulfonohydrazide (VIa) failed to give the expected 1,4‐bisthiophenesulfonylpyrazole.
Synthesis of some 3‐substituted [1,8]naphthyrido[3,2‐c][1,8]naphthyridines. A new heterocyclic ring system
Authors: Ferrarini Pier Luigi , Biagi Giuliana , Livi Oreste , Primofiore Giampaolo , Carpenè Marino
Published: March 2009

Some 3‐substituted‐5,6‐dihydro[1,8]naphthyrido[3,2‐c][1,8]naphthyridines (V) were obtained by the condensation of 7‐substituted‐2,3‐dihydro‐1,8‐naphthyridin‐4‐(1H)ones (IV) with 2‐aminonicotinaldehyde. All of the 5,6‐dihydro derivatives V were transformed into the fully aromatic compounds VI by refluxing with nitrobenzene.
Synthesis of pyridinium heterocyclic ylides. Degradation of the pyridinium group
Authors: Esteve Marta E. , Gaozza Carlos H.
Published: March 2009

The synthesis of pyridinium‐quinolone chlorides and ylides, a pyridinium‐methylquinazolone ylide, 9‐pyridinium acridine chloride, and their behaviour by treatment with boiling aniline are described.
Reaction of sulfene with heterocyclic N,N‐disubstituted α‐aminomethyleneketones. VII. Synthesis of 1,2‐oxathiino‐[5,6‐g]benzothiazole derivatives
Authors: Mosti Luisa , Menozzi Giulia , Schenone Pietro
Published: March 2009

The polar 1,4‐cycloaddition of sulfene to N,N‐disubstituted 6‐aminomethylene‐5,6‐dihydro‐2‐phenylbenzothiazol‐7‐(4H)ones gave, generally in good yield, N,N‐disubstituted 3,4,5,6‐tetrahydro‐8‐phenyl‐1,2‐oxathiino‐[5,6‐g]benzothiazol‐4‐amine 2,2‐dioxides, which are derivatives of the new heterocyclic system 1,2‐oxathiino‐[5,6‐g]benzothiazole. This reaction did not occur only with the N,N‐diphenylenaminone.
Condensation reaction of 3,4‐dibenzoyl‐1‐methyl‐2,5‐diphenylpyrrole and ‐1‐phenylpyrazole with methylamine derivatives affording pyrrolo [3,4‐c]pyridine and 2H‐pyrazolo[3,4‐c]‐ and [4,3‐c]pyridines
Authors: Mataka Shuntaro , Takahashi Kazufumi , Tashiro Masashi
Published: March 2009

The reaction of 3,4‐dibenzoyl‐1‐methyl‐2,5‐diphenylpyrrole (1) and ‐1‐phenylpyrazole (2) with methylamines (3a‐c) afforded pyrrolo[3,4‐c]pyridine (4), and isomeric 2H‐pyrazolo[3,4‐c]pyridines (5a‐c) and [4,3‐c]pyridines (6a‐c), respectively.
Cyclic isothioureido compounds. II. Reaction of trans‐3a,4,5,9b‐tetrahydronaphth[1,2‐d]‐imidazoline‐2‐thiones with α‐bromoketones
Authors: Hara Takeshi , Kayama Yasutaka , Fukushima Hisashi
Published: March 2009

The reaction of trans‐3a,4,5,9b‐tetrahydronaphth[1,2‐d]imidazoline‐2‐thiones (8) with α‐bromoketones gave, depending upon the structure of the α‐bromoketones, reaction solvent and reaction temperature, the hydrobromides of tetrahydronaphth[1,2‐d]imidazolin‐2‐ylthiomethyl ketone (10), hexahydro‐8‐hydroxynaphth[1′,2′:4,5]imidazo[2,1‐b]thiazoles (5, 11, 19 and 20) or tetrahydronaphth[1′,2′:4,5]imidazo[2,1‐b]‐thiazoles (12 and 16). Structural determinations based on ir and nmr spectroscopies are discussed.
On the reactivity of 1‐(p‐bromophenyl)‐2‐methyl‐5‐bromopyridazine‐3,6‐dione with aliphatic amines
Authors: Baloniak Sylwester , Van Der Plas Henk C.
Published: March 2009

Reaction of 5‐bromo‐1‐(p‐bromophenyl)‐2‐methylpyridazine‐3,6‐dione with morpholine leads to formation of 1‐(p‐bromophenyl)‐2‐methyl‐5‐morpholinopyridazine‐3,6‐dione. The structure of the morpholino compound was established by the chemical methods and an X‐ray crystal structure determination.
Synthesis of a rotenone‐like benzopyranobenzopyranone
Authors: Peet Norton P. , Sunder Shyam
Published: March 2009

The synthesis of a novel rotenone‐like molecule, 9‐methoxy‐8‐methyl‐6,6a,12,12a‐tetrahydro[1]benzopyrano‐[3,4‐b][1]benzopyran‐12‐one (2) is described. Efficient syntheses of 3,4‐dihydro‐2H‐[1]benzopyran‐3‐one (9) from ethyl 3‐hydroxy‐2H‐[1]benzopyran‐4‐carboxylate (6), an intermediate in the synthesis of2, were developed. Thermolysis of6and9in decalin yielded 6,8‐dihydro‐14H‐bis[1]benzopyrano[3,4‐b:4′,3′‐e]pyran‐14‐one (8), which has previously been described. Also produced in the thermolysis was the isomeric 1H‐bis[1]‐benzopyrano[3,4‐b:3′,4′‐á]pyran‐7‐(9H)one (10), the first member of a novel, pentacyclic ring system.
Approaches to phenazine‐derivedN‐isosteres of anthracyclinones
Authors: Acton Edward M. , Tong George L.
Published: March 2009

1‐Hydroxyphenazine 5,10‐dioxide showed antitumor properties against mouse leukemia P388. It also participated in biochemical mechanisms of quinoid antitumor agents, as indicated by inhibition of radiolabeled DNA‐RNA precursors in cultured leukemia L1210 cells and by stimulation of oxygen consumption in mammalian microsomes. This suggests that the isosteric di‐N‐oxide system may be a biologically active substitute for 1,4‐quinone, and that di‐N‐oxides of tetrahydrobenzo[b]phenazines can be explored as anthracyclinoneN‐isosteres. As potential synthetic intermediates, 7,8,9,10‐tetrahydro‐6,11‐dihydroxybenzo[b]‐phenazines have been prepared by 1) Diels‐Alder addition of phenazine‐1,4‐quinone and 1‐methoxy‐3‐(trimethylsilyloxy)‐1,3‐butadiene to give isolable but labile adducts and 2) condensation of 6,7‐diamino‐1,2,3,4‐tetrahydro‐2‐hydroxy‐5,8‐dimethoxy‐2‐naphthoic acid with 3‐methoxy‐1,2‐quinone. Attempts atN‐oxidation gave instead oxidation of the 6,11‐hydroquinone ring to quinone, regardless of hydroxyl protection. Despite previous literature indications, we have been unable to synthesize the 1,4‐dihydroxyphenazine 5,10‐dioxide system. We conclude that this hydroxyl substitution pattern (1,4) in an adjacent ring must be avoided in the redesign of anthracyclinone isosteres that have diN‐oxide in place of quinone.
1,3‐dipolar addition of pyridine N‐imine to acetylenes and the use of C‐13 NMR in several structural assignments
Authors: Anderson Paul L. , Hasak James P. , Kahle Alicia D. , Paolella Nicholas A. , Shapiro Michael J.
Published: March 2009

Addition of pyridine‐N‐imine to a variety of acetylenic mono‐ (Scheme I) and di‐ (Scheme II) carboxylic ester dipolarophiles was carried out. Several of the 3‐azapyrrocoline esters obtained were further converted into acids, amides and hydrazides as shown in Schemes I and II.
Polycondensed nitrogen heterocycles. X. 5,6,7,8‐Tetrahydropyrrolo[1,2‐e][1,5]benzodiazocin‐7‐ones. A new ring system
Authors: Aiello Enrico , Dattolo Gaetano , Cirrincione Girolamo , Almerico Anna Maria , D'Asdia Isabella
Published: March 2009

The synthesis of a new heterocyclic ring system is described. Condensation of 1,4‐diketones 1a,b with β‐alanine gave the substituted propionic acids 2a,b which upon reduction with palladium on charcoal afforded compounds 3a,b. Title compounds 4a,b were obtained by refluxing 3a,b in toluene with p‐toluenesulphonic acid as catalyst.
Studies on quinones. VII. Synthesis of some benzo[b]thiophene‐4,7‐diones
Authors: Ruiz V. M. , Tapia R. , Valderrama J. , Vega J. C.
Published: March 2009

The synthesis of methyl 4,7‐dihydro‐4,7‐dioxobenzo[b]thiophene‐2‐carboxylate (20) based on the reaction of methyl mercaptoacetate with activated 1,4‐benzoquinones is described. Methyl 4,7‐dihydro‐4,7‐dioxo‐5‐hydroxybenzo[b]thiophene‐2‐carboxylate (24) and its corresponding methyl ether 26 were obtained through a Thiele‐Winter acetoxylation on 20. On the basis of the properties of methyl 4,7‐dihydro‐4,7‐dioxo‐6‐methoxy‐benzo[b]thiophene‐2‐carboxylate (21) obtained from 2,4,5‐trimethoxybenzaldehyde (32), the structures of the products 24 and 26 are proposed.
Chemistry of the phenoxathiins and isosterically related heterocycles. XVII. First synthesis of a benzoxathiinopyridazine and the determination of structure by 13C‐NMR: 1‐Methoxy‐3,4‐diazaphenoxathiin
Authors: Womack Charles H. , Martin Gary E.
Published: March 2009

The reaction of 5‐methoxy‐3,4‐dichloropyridazine with the disodium salt of o‐mercaptophenol leads to the formation of 1‐methoxy‐3,4‐diazaphenoxathiin as the sole product of the reaction. The structure of the isolated product was confirmed by 13C‐nmr spectroscopy, with the development of arguments to discriminate the isolated compound from 4‐methoxy‐1,2‐diazaphenoxathiin, the other product possible in this reaction. Mechanistic considerations in the formation of the isolated product are discussed.
2′,3′,4′,9′‐Tetrahydrospiro[cyclohexane‐1,1′‐(1h)pyrido[3,4‐b]indol]‐2‐ones and their transformations into 2,3,4,4a,5,6,9,14‐octahydro‐4a‐hydroxy‐1h,8h‐pyrido[3,4‐b:2,1‐i']diindole‐5‐carbonitriles and 5‐substituted 2,3,4,4a,9,14‐hexahydro‐4a‐hydroxy‐1H,8H‐indolo[2′,3′:3,4]‐pyrido[1,2‐c]benzimidazol‐6‐(5H)ones
Authors: Bobowski George
Published: March 2009

The condensation of 1H‐indol‐3‐ethanamine derivatives 1 with 1,2‐cyclohexanedione (2) and subsequent transformation of the resulting 2‐[[2‐(1H‐indol‐3‐yl)ethyl]imino]cyclohexanones (3) into 2′,3′,4′,9′‐tetrahydrospiro[cyclohexane‐1,1′‐(1H)pyrido[3,4‐b]indol]‐2‐ones 4 using Pictet‐Spengler reaction conditions is described. The reaction of 4 with acrylonitrile gave a mixture of pentacyclic derivatives, 2,3,4,4a,5,6,9,14‐octahydro‐4a‐hydroxy‐1H,8H‐pyrido[3,4‐b:2,1‐i']diindole‐5‐carbonitriles 12. Treatment of 4 with alkyl and aryl isocyanates (14) at room temperature gave 5‐substituted‐2,3,4,4a,9,14‐hexahydro‐4a‐hydroxy‐1H,8H‐indolo[2′,3′:3,4]pyrido[1,2‐c]benzimidazol‐6‐(5H)ones 16. Dehydration of 16 gave 5‐substituted‐2,3,9,14‐tetra‐hydro‐1H,8H‐indolo[2′,3′‐3,4]pyrido[1,2‐c]benzimidazol‐6‐(5H)ones (17). Spectral and chemical evidence is presented to confirm structures 4, 12, 16, and 17.
Synthesis and biological activity of some new 3‐and 6‐substituted coumarin amino acid derivatives. Part I
Authors: El‐Naggar A. M. , Ahmed F. S. M. , El‐Salam A. M. Abd , Radi M. A. , Latif M. S. A.
Published: March 2009

The synthesis of 6‐nitrocouarrain‐3‐CO‐amino acids and their corresponding methyl esters (II‐XVII) and some dipeptide methyl esters (XVIII‐XXVI) are described. 6‐(N‐Tosyl‐ or N‐phthalylaminoacyl)aminocoumarin‐3‐carboxylic acid methyl esters (XXXIV‐XL) and 3‐(N‐phthalyl‐ or N‐tosylaminoacytyaminocoumarins (XLV‐LVI) have been prepared via the carbodiimide and acid chloride methods. Hydrazinolysis of 3‐ or 6‐(N‐phthalylaminoacyl)aminocoumarin derivatives in tetraline gave the corresponding 3‐ and 6‐(aminoacyl)aminocoumarins and the carboxylic acid hydrazides (XLI‐LVIII), respectively. 3‐(N‐Tosyl‐L‐Val‐L‐Leu‐)aminocoumarin (LIX) was synthesized via the azide method. Twenty four of various substituted 3‐ and 6‐aminoacylcoumarin derivatives were found to possess specific antimicrobial activities towards different microorganisms.
Some reactions of 4H‐pyrylium salts with tributylphosphine and with tertiary amines
Authors: Reynolds G. A. , Chen C. H.
Published: March 2009

The phosphonium salt from tributylphosphine and 2,6‐di(4‐methoxyphenyl)pyrylium perchlorate (3) reacted with diisopropylethylamine in acetonitrile to give 2,2′,6,6′‐tetra(4‐methoxyphenyl)‐Δ4.4′‐bi‐4H‐pyran in quantitative yield. The reaction of 3 and other 4H‐pyrylium salts with tertiary amines gave 4H‐pyrans.
Reaction of ketenes with N,N‐disubstituted α‐aminomethyleneketones. XI. Synthesis of 2H‐pyrano[3,2‐g]benzothiazole derivatives
Authors: Mosti Luisa , Menozzi Giulia , Schenone Pietro
Published: March 2009

Cycloaddition of dichloroketene to N,N‐disubstituted 6‐aminomethylene‐5,6‐dihydro‐2‐phenylbenzothiazol‐7‐(4H)ones gave in good yield N,N‐disubstituted 4‐amino‐3,3‐dichloro‐3,4,5,6‐tetrahydro‐8‐phenyl‐2H‐pyrano[3,2‐g]benzothiazol‐2‐ones II, which are derivatives of the new heterocyclic system 2H‐pyrano[3,2‐g]benzothiazole.

Dehydrochlorination with triethylamine of II afforded N,N‐disubstituted 4‐amino‐3‐chloro‐5,6‐dihydro‐8‐phenyl‐2H‐pyrano[3,2‐g]benzothiazol‐2‐ones III in good to moderate yield. The dimethylamino adduct was dehydrochlorinated in high yield by refluxing in toluene, whereas the diisopropylamino adduct gave in low yield 6‐(2,2‐dichloroethylidene)‐5,6‐dihydro‐2‐phenylbenzothiazol‐7‐(4H)one with the triethylamine treatment. The dehydrochlorinated product IIId (NR2 = pyrrolidino) was obtained directly in low yield by cycloaddition of dichloroketene to the corresponding enaminone. Full aromatisation of IIIa,g [NR2 = N(CH3)2 and N(CH3)C6H5, respectively] to the corresponding N,N‐disubstituted 4‐amino‐3‐chloro‐8‐phenyl‐2H‐pyrano‐[3,2‐g]benzothiazol‐2‐ones was accomplished with DDQ in refluxing benzene.
Synthesis and biological activity of 2‐substituted‐3‐ethyl‐N‐alkyl/arylindoles
Authors: Kumar Ashok , Agarwal J. C. , Nath C. , Gurtu S. , Sinha J. N. , Bhargava K. P. , Shanker K.
Published: March 2009

Some new2‐substituted‐N‐(aminomethylaryl/aminoethylaryl)indole‐3ylglyoxylamides3a‐hand their corresponding 2‐substituted‐3‐ethyl‐N‐alkyl/aryl indoles4a‐d,f,gwere synthesized. These compounds were evaluated for their cardiovascular as well as antiparkinsonian activities.
Heterocyclic β‐Enamino esters. 28. The reaction of heterocyclic β‐Enamino esters and nitriles with cyclic amidines. A simple route to azolopyrimidines
Authors: Elnagdi Mohamed H. , Wamhoff Heinrich
Published: March 2009

Whereas 2‐amino‐3‐ethoxycarbonyl‐4,5‐dihydrofurans Ia‐c condense with 5‐membered amidine derivatives, via elimination of ethanol to afford the azolopyrimidines IIIa,b, XI, and XIVa,b, the 2‐amino‐3‐cyano‐4,5‐dihydrofurans Id,e give with the same reagents, under elimination of ammonia, the novel ring systems of furo‐azolopyrimidines XVIII and XXa,b. 2‐Amino‐3‐ethoxycarbonyl‐5,6‐dihydro‐4H‐thiopyrane (XXI) reacts with 5‐amino‐1,2,4‐triazole (II) to yield the triazolo[1,5‐a]pyrimidine XXII, and with 2‐aminobenzimidazole to XXIII. The mechanism of these reactions is discussed. XIVb and VIIb are cyclized in a secondary step to give the novel furo[2,3‐d]benzimidazo[1,2‐a]pyrimidine XXVI, and furo[2,3‐d]‐1,2,4‐triazolo[1,5‐a]pyrimidine XXVIII respectively, besides the acetoxy derivatives XVII and XXIX.
Neue 1,5‐benzodiazepinderivate
Authors: Capuano Lilly , Gärtner Klaus
Published: March 2009

The 1,5‐benzodiazepines 1,6 add benzoylphenylketene (3) across the azomethine bond to produce the 1,3‐oxazino[3,2‐a]‐1,5‐benzodiazepines 4,5,7. In 6a azo coupling occurs at the exocyclic methyl group leading to the formation of 10, while diazo group transfer takes place at the cyclic methylene group to afford 11. The latter compounds react with 3 without loss of the diazo nitrogen, yielding the diazo‐oxazinobenzodiazepine 12; whereas, by interaction with phenyl isocyanate, the pyrazolo[4,3‐b]‐1,5‐benzodiazepine 14 is formed.
Synthesis and structure of heterocyclic compounds. 1‐Amino‐2,4‐Disubstituted imidazoles
Authors: Cerioni Giovanni , Cocco Maria Teresa , Congiu Cenzo , Maccioni Antonio
Published: March 2009

A synthesis of 1‐aminoimidazoles by reaction between α‐halogenoketones and N‐acetylamidrazones is described. Structure and position of substituent groups in the synthesized aminoimidazoles were established by spectroscopical methods.
Chemistry of thienopyridines. XXVIII. Mass spectra of fourteen substituted thienopyridines and nmr spectra of four picrates
Authors: Klemm L. H. , Shabtai J. , Michaud Joan , Louris John N.
Published: March 2009

Electron‐impact mass spectra are presented for various substituted thieno[2,3‐b]‐ and thieno[3,2‐b]‐pyridines. In particular, it is shown that chemical structures of alkylthienopyridines can be correlated (a) with their mass spectral fragmentation patterns and (b) with the proton magnetic resonance spectra of their picrate salts.
Utilization of deuterium labelling and 13C NMR spectroscopy in the investigation of the condensation of 1‐Methyl‐5‐nitroimidazole‐2‐aldehyde and 2‐Amino‐4‐methylpyrimidine
Authors: Bradamante Silvia , Colombo Silvana , Vittadini Giorgio
Published: March 2009

The product obtained condensing l‐methyl‐5‐nitroimidazole‐2‐aldehyde with 2‐amino‐4‐trideuteriomethyl‐pyrimidine and showing total deuterium incorporation at one of the olefinic carbons and partial deuterium incorporation para to the amino group, served to assign 13C and 1H resonances in the condensation products 3. The nature of the species undergoing condensation has been inferred from labelling experiments and from 1H and 13C nmr spectra of precursors and products in dimethylsulfoxide and trifluoroacetic acid.
Studies in the heterocyclic series. XX. 1,4‐Diazaphenoxazine and related compounds
Authors: Okafor Charles O.
Published: March 2009

As part of our program on the synthesis of new psychotropic agents, the parent rings of two diazaphenox‐azines are described. The reaction of 2‐aminophenol and 2,3‐dichloropyrazine in alkaline media gave good yields of 1,4‐diazaphenoxazine. Replacement of 2,3‐dichloropyrazine with 2,3‐dichloroquinoxaline gave on the other hand the heterocycle, 1,4‐diazabenzo[b]phenoxazine. Nitration and S‐oxide formation were achieved by reaction with mixed nitric and sulfuric acids. Mechanistic pathways to these compounds were also discussed.
The chemistry of polycyclic arene imines. I. Substitution at the nitrogen atom of 1a,9b‐dihydro‐1H‐phenanthro[9,10‐b]azirine
Authors: Weitzberg Moshe , Aizenshtat Zeev , Blum Jochanan
Published: March 2009

Chlorides of carboxylic, sulfonic and phosphoric acids proved to convert phenanthrene‐9,10‐imine into the corresponding rearranged acet‐ sulfon‐ and phosphonamidophenanthrene. Trimethylchlorosilane and N,O‐bis(trimethylsilyl)acetamide reacted with the imine without destruction of the aziridine ring. The silylated compound could be transferred into the respective N‐substituted phenanthrene‐9,10‐imines when treated with acetyl‐, methanesulfonyl‐, 4‐tosyl‐ and diethylphosphoryl chloride. A remarkably stable N‐chlorophenanthrene‐9,10‐imine was obtained from the unsubstituted compound and N‐chlorosuccinimide.
Synthesis of sulfur‐bridged piperazinediones by reaction of 3,6‐dibromo‐1,4‐dimethyl‐2,5‐piperazinedione with geminal dithiols
Authors: Srinivasan Ananthachari , Kolar Aldean J. , Olsen Richard K.
Published: March 2009

The reaction of several geminal dithiols with 3,6‐dibromo‐1,4‐dimethyl‐2,5‐piperazinedione gave in good yields piperazinedione derivatives substituted at the 3,6‐position with a geminal dithiol‐bridging group. These sulfur‐bridged piperazinediones formally represent derivatives of the 2,4‐dithia‐6,8‐diaza‐7,9‐dioxobicyclo[3.2.2]nonane ring system. Attempts to transform these sulfur‐bridged piperazinediones to 3,6‐epidithiopiperazinediones by removal of the bridging group common to the sulfur functionality were unsuccessful. Studies also are reported of addition of thioacetic acid to 3,6‐dimethylene‐2,5‐piperazinedione to give 3,6‐diacetylthio‐3,6‐dimethyl‐2,5‐piperazinedione. Conversion of the 3,6‐diacetylthio derivative to the epithiopiperazinedione ring system yielded a mixture of epimono‐ and epidithiopiperazinediones.
A convenient synthesis of 9H‐dibenz[c,f]imidazo[1,2‐a]azepin‐9‐ones
Authors: Houlihan William J. , Parrino Vincent A.
Published: March 2009

A convenient three step synthesis of 9H‐dibenz[c,f]imidazo[1,2‐a]azepin‐9‐ones from readily available 2‐phenylimidazoline and a methyl benzoate is described.
Mutagenic heterocyclic nitrogen compounds related to protein pyrolysates. 1. Derivatives of dipyrido[1,2‐a:3′,2′‐d]imidazole
Authors: Saint‐Ruf G. , Loukakou B. , N'Zouzi C.
Published: March 2009

2‐Amino‐6‐methyldipyrido[1,2‐a:3′‐2′‐d]imidazole is one of the mutagenic principles of L‐glutamic acid and casein pyrolysates. We prepared several isomeric amines of this compound, as well as their homologues methylated in different positions on the heterocyclic ring, either by nitration of the ring followed by reduction or from appropriate 4‐azidodipyrido[1,2‐a:3′,2′‐d]imidazoles. The latter compounds, the heterocyclic ring itself and various functional derivatives (hydroxylated, carboxylated, hydrazinic) were synthesized from 2‐aminoimidazo[1,2‐a]pyridines via various reactions which are described herein.
Thermal decompositions of dinitropyridyl and dinitrothienyl dithiocarbamates and t‐butyl trithiocarbonates
Authors: Rasheed Khalid , Warkentin James D.
Published: March 2009

The title compounds on heating cyclized to yield 7‐nitro‐1,3‐dithiolo[4,5‐c]pyridin‐2‐one (III), 6‐nitro‐1,3‐dithiolo[2,3‐c]pyridin‐2‐one (VIIa), 6‐nitrothieno[2,3‐d]‐1,3‐dithiol‐2‐one (XIVa) and 6‐nitrothteno[2,3‐d]‐1,3‐dithiole‐2‐thione (XIVb).
Studies in the heterocyclic series. XXI. A novel tetraaza‐analog of phenothiazine
Authors: Okafor Charles O. , Uche Imaga O. , Akpanisi Leonard E. S.
Published: March 2009

As a continuation of our search for new pharmaco‐active phenothiazine compounds, the synthesis of 1,4,6,8‐tetraazabenzo[b]phenothiazine ring system is described. Derivatives of this new heterocycle were prepared by converting 4,5‐diamino‐6‐hydroxypyrimidine to 4,5‐diaminopyrimidine‐6‐(1H)thione followed by the action of 2,3‐dichloroquinoxaline in refluxing DMF or DMAC. The reaction of mixed nitric and sulfuric acids with 9‐amino‐12‐chloro‐1,4,6,8‐tetraazabenzo[b]phenothiazine gave 9‐amino‐12‐chloro‐13‐nitro‐1,4,6,8‐tetraazabenzo[b]phenothiazine 5‐oxide in satisfactory yields. Diazotization of 9‐amino‐1,4,6,8‐tetraazabenzo‐[b]phenothiazine led to 1,4,6,8‐tetraazatriazolo[4,5,1‐kl]benzo[b]phenothiazine which is a new heterocyclic compound and the parent compound of this ring system. The mechanistic pathways to these compounds are also proposed.
Preparation of N‐aryl‐2,4‐diaminopentanes by the ring opening reaction of 1‐aryl‐3,4,5,6‐tetrahydro‐2‐(1H)pyrimidinones
Authors: Kashima Choji , Katoh Akira , Yoshiwara Nobutoshi , Omote Yoshimori
Published: March 2009

1‐Aryl‐3,4,5,6‐tetrahydro‐2‐(1H)pyrimidinones (I) underwent reductive ring opening reaction with lithium aluminum hydride to afford N‐aryl‐2,4‐diaminopentanes (II) in good yields. On the other hand, 3,4,5,6‐tetrahydro‐3,4,6‐trimethyl‐1‐phenyl‐2‐(1H)‐pyrimidinone (V) gave only cyclic diamine, 3,4,6‐trimethyl‐1‐phenylhexahydropyrimidine (VI), in 60% yield.
Synthesis of nitrobenzothiazolinethiones and related compounds via intramolecular displacement of nitro groups
Authors: Rasheed Khalid , Warkentin James D.
Published: March 2009

A number of dinitroanilines on reaction with sodium hydride in dimethylformamide produced the sodium salt which, on further reaction with carbon disulfide, cyclized to nitrobenzothiazolinethiones. In several cases benzothiazolinethione sulfides and benzothiazolinethione disulfides were also isolated.
A reinvestigation of the cyclodesulfurization of thiosemicarbazides
Authors: Sunder Shyam , Peet Norton P. , Barbuch Robert J.
Published: March 2009

A recent report describing the preparation of 2‐(substituted‐amino)‐3,4‐dihydro‐5H‐1,3,4‐benzotriazepin‐5‐ones (3), by the cyclodesulfurization of hydrazides prepared from o‐aminobenzoylhydrazine (1) and isothiocyanates, is erroneus. The products resulting from this reaction sequence are, instead, 2‐(substituted‐amino)‐5‐(o‐aminophenyl)‐1,3,4‐oxadiazoles (4). Alternate syntheses of the oxadiazoles led to the correct structural assignments.
The preparation of selenium‐containing aromatic and heterocyclic C‐substituted α‐amino acetic acid derivatives of potential biomedical application
Authors: Sadeh Tsvi , Davis Michael A. , Gil Ran , Zoller Uri
Published: March 2009

Model selenium‐containing aromatic and heterocyclic C‐substituted α‐amino acid compounds have been synthesized as potential biomedical organ scanning application (external imaging) agents. The synthesis is based on the amidoalkylation of aromatic and heterocyclic compounds with α‐hydroxyglyoxylic acid‐primary amide adducts (2). The procedure is simple and straightforward, the overall yields are good, and the method appears to be of general use for the preparation of a wide variety of selenium‐containing amino acids (4).
Functionalization of substituted 2‐(1H)pyridones. II. Synthetic pathways to c‐6 modified 3‐cyano‐ and 3‐carboxy‐2‐(1H)pyridones from a common precursor
Authors: Showalter H. D. Hollis , Domagala John M. , Sanchez Joseph P.
Published: March 2009

Starting from readily available 1,2‐dihydro‐6‐methyl‐2‐oxo‐3‐pyridinecarbonitrile, 1, viable synthetic pathways to a number of C‐6 functionalized 1,2‐dihydro‐2‐oxo‐3‐pyridinecarbonitriles and corresponding acids are presented. Through the utilization of dianion chemistry, the C‐6 methyl substituent is selectively functionalized to three different oxidation levels.
Metal‐chelating 1,3‐bis(2′‐pyridylimino)isoindolines
Authors: Siegl Walter O.
Published: March 2009

A variety of novel chelating 1,3‐bis(2′‐pyridylimino)isoindoline ligands were prepared and characterized including ligands substituted on both the pyridyl and isoindoline ring systems. Noteworthy are the first iso‐indoline ligands with solubility in aqueous media. A convenient preparation of 4‐alkoxyphthalonitriles is reported; these compounds are readily obtained from 4‐nitrophthalonitrile and are suitable starting materials for alkoxy‐substituted ligands.