bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nucleophilic displacements on polyhalogenated heterocyclic N‐methoxy methyl sulfates
Authors: Bublitz D. E. 
Published: March 2009

AbstractN‐Methoxy methyl sulfates of 2,3,4,5‐ and 2,3,5,6‐tetrachloropyridine, 3,4,5‐ and 3,4,6‐trichloropyridazine, pentachloropyridine, and tetrachloropyridazine have been prepared. Their reactions with water and aqueous potassium cyanide have been investigated.
Reissert compound studies. Cyclization of N‐(ω‐chloroalkanoyl)reissert compounds
Authors: Gibson Harry W. , Chesney Dennis K. , Popp Frank D. 
Published: March 2009

AbstractTreatment of 2‐(4‐chlorobutanoyl)‐ and 2‐(5‐chloropentanoyl)‐1, 2‐dihydroisoquinaldonitrile with sodium hydride gave rise to tricyclic benzoquinolizone and azepino[1,2‐α]isoquinoline derivatives. A similar reaction was observed in the quinoline series. Several reactions of 1,2,3,4‐tetrahydro‐4‐oxo‐11bH‐benzo[α]quinolizine‐11b‐carbonitrile are reported.
On the mechanism of the 1,2‐cycloaddition of azobenzenes to ketenimines
Authors: Barker Marvin W. , Jones Raymond H. 
Published: March 2009

AbstractThe 1,2‐cycloaddition of unsymmetrical azobenzenes has been found to be stereoselective and the rate is essentially solvent independent. These observations lead to the postulation of a near concerted process which encounters a steric effect after alignment.
The mass spectra of small‐ring heterocycles. III. Aroylaziridines
Authors: Cromwell Norman H. , Woller Paul B. , Baumgarten Henry E. , Parker Richard G. , Minden David L. Von 
Published: March 2009

AbstractThe mass spectra of cis‐trans isomeric aroylaziridines are presented. Attempts to extend the method for distinguishing between cis and trans isomers previously established for aroylazetidines are described and the results rationalized. A simple fission of the 1‐alkylnitrogen bond is described and detailed fragmentation mechanisms are presented and discussed.
Mass spectra of some 1,2,4‐thiadiazoles
Authors: Potts K. T. , Armbruster R. 
Published: March 2009

AbstractSubstituted 1,2,4‐thiadiazoles were found to undergo fragmentation by loss of RCN from the molecular ion with both 3‐ and 5‐substituents being involved to some extent. This was followed by loss of sulfur to yield a nitrilium ion. With 5‐hydrazino substituents, hydrogen transfer was observed from the substituent to a ring nitrogen atom.
The preparation of 3‐aminoanthyridine
Authors: Carboni S. , Da Settimo A. , Bertini D. , Ferrarini P. L. , Livi O. , Tonetti I. 
Published: March 2009

AbstractNitration of anthyridine‐2,6‐dione (I) gave 7‐nitroanthyridine‐2,6‐dione (II). Treatment of this compound with phosphorus pentasulfide afforded 7‐aminoanthyridine‐2,6‐dithione (III). Desulfurization of the thioderivative III with Raney Nickel and subsequent aromatization of 3‐amino‐5,10‐dihydroanthyridine (VI) in boiling nitrobenzene, gave 3‐aminoanthyridine (VII) in satisfactory yield. The structure of 3‐aminoanthyridine was demonstrated and its physico‐chemical features are not in agreement with that previously reported in literature. The preparation of 3‐aminoanthyridine‐5‐one (XII) is also described.
Synthesis of 8,9‐dialkoxy‐substituted tetrahydrobenz[h] isoquinolines
Authors: Zee‐Cheng Kwang Y. , Nyberg Wayne H. , Cheng C. C. 
Published: March 2009

Abstract6,7‐Dimethoxy‐2‐naphthylethylamine, prepared by the diborane reduction of 6,7‐dimethoxy‐2‐naphtlialeneacetamide, underwent a Pictet‐Spengler cyclization to form 8,9‐dimethoxy‐1,2,3,4‐tetrahydrobenz[h]isoquinoline. This compound is identical with that obtained by reduction of the corresponding dihydrobenzisoquinoline prepared from formamide cyclization. 6,7‐Dialkoxy‐2‐naphthaleneacetic acids, the key intermediates for the preparation of these amides, were obtained from 6,7‐dialkoxy‐2‐acetonaphthones by a modified Willgerodt reaction.
Alkyl N‐methylfuroxanylcarbamates. Synthesis and structure. II
Authors: Gasco A. , Mortarini V. , Ruà G. , Menziani E. 
Published: March 2009

AbstractFrom 3‐methyl‐4‐furoxancarboxylic acid hydrazide and 4‐methyl‐3‐furoxancarboxylic acid hydrazide the corresponding azides have been synthesized. 3‐Methyi‐4‐furoxancarboxylic acid azide normally underwent the Curtius reaction to give the expected carbamic acid derivative. The degradation of 4‐methyl‐3‐furoxancarboxylic acid azide led to the N‐(4‐methylfuroxan‐3‐yl)‐carbamic acid derivative at low temperatures and to N‐(3‐methylfuroxan‐4‐yl)carbamic acid derivative at higher temperatures.
On the nitration of 2‐benzylthiophene and the spectroscopic behaviour of nitro‐2‐benzylthiophenes
Authors: Arcoria A. , Maccarone E. , Musumarra G. , Romano G. 
Published: March 2009

AbstractNitration of 2‐benzylthiophene with nitric acid (molar ratio 1:1) in acetic anhydride gave only nitro‐2‐benzylthiophenes, indicating the benzene ring is unreactive to this electrophilic substitution. The main reaction product was 2‐benzyl‐5‐nitrothiophene (about 87%) the amounts of the 3‐nitro and 4‐nitro isomers were about 10% and 3%, respectively. These percentages, determined by glc and nmr techniques, were found to be constant using various nitration conditions. The syntheses of the nitro‐2‐benzylthiophenes are described, together with some spectroscopic properties.The uv spectra confirm that the conjugation of the nitro group in the α position is greater than in the β position. The isomer structures have been assigned by nmr chemical shifts and coupling constant of the thiophene protons. Also infrared spectra are briefly considered.
Synthesis of (±)‐laudanoeine and a study of 1‐benzyl‐3‐isoquinoione intermediates
Authors: Elliott I. Wesley 
Published: March 2009

AbstractA keto acid (2) has been converted to tetrahydropapaverine and (±)‐laudanosine. Some intermediate 3‐isochromanone (3) and 3‐isoquinolone (4 and 5) derivatives have been investigated and structures assigned to these compounds from spectroscopic studies. The 3‐isoquinolone tautomer with the o‐quinonoid structure predominates over the 3‐isoquinolinol form, but the analogous oxygen derivative has preferentially a stilbene structure (3) with an intact benzene system.
Synthesis of 3‐substituted N‐aminopyridinium salts
Authors: Tamura Yasumitsu , Miki Yasuyoshi , Honda Toshiko , Ikeda Masazumi 
Published: March 2009

AbstractRing opening of N‐(2,4‐dinitrophenyl)pyridinium chlorides with hydrazine followed by recyclization resulted in the formation of N‐aminopyridinium salts. The scope of this reaction sequence was determined and several new 3‐substituted N‐aminopyridinium salts were prepared.
Endocyclic vs exocyclic olefin formation from 4‐piperidones via the wittig reaction
Authors: Borne Ronald F. , Aboul‐Enein Hassan Y. 
Published: March 2009

AbstractThe reaction of 1‐methyl‐4‐piperidone and 1‐benzoyl‐4‐piperidone with triethyl phosphono‐acetate in the presence of excess base yields both the endocyclic and exocyclic olefins. However, treatment of 1‐methyl‐4‐piperidone with diethyl cyanomethylphosphonate, even in the presence of excess base, yielded only the exocyclic olefin. Factors affecting isomer distribution during the course of the reaction are presented. The isolation of an exocyclic tetrahydropyridine from the sodium borohydride reduction of the methiodide of 4‐pyridylacetonitrile is reported.
The crystals and molecular structure of 1,1,4,4‐Tetraphenyl‐2,5‐di‐(t‐butyl)‐1,4‐diphosphoniacyclohexadiene‐2,5‐dichloride
Authors: Cheung L. D. , Trefonas L. M. 
Published: March 2009

AbstractThe crystal and molecular structure of the title compound has been determined by single crystal, x‐ray diffraction techniques. The compound crystallizes in a monoclinic space group of C2/c symmetry with four molecules in a unit cell of dimensions a = 24.578(1), b = 10.503(1), c = 17.579(1) Å and (3 = 1.30.93 ± .01°. The unit cell also contains two waters of crystallization which are involved in hydrogen bonds to the chloride ions. The central ring has been shown to be a diene which resides in a boat conformation defined by dihedral angles of 157°. The structure has been refined to a value of R = 0.08 using the 1535 statistically significant reflections measured out ot a 2θ value of 140°.
Naphthyridine chemistry. XVI. A literature correction —The preparation of 2,4‐Dimethyl‐7‐ethoxy‐1,8‐naphthyridine 1‐Oxides
Authors: Vandahm Richard A. , Pokorny David J. , Paudler William W. 
Published: March 2009

AbstractThe N‐oxidation of 2,4‐dimethyl‐7‐ethoxy‐1,8‐naphthyridine has been shown to afford the 1‐oxide rather than the 1,8‐dioxide as reported by others.
Reactions of substituted pyridines and their N‐oxides with ethanolic sodium hydroxide and various alkoxides
Authors: Muth Chester W. , Darlak Robert S. , Patton Jesse C. 
Published: March 2009

Abstract2‐Benzoylpyridine 1‐oxide with ethanoiic sodium hydroxide yielded acyl nucleophilic displacement products and a redox product, 2‐(α‐hydroxybenzyl)pyridine. 3‐Benzoylpyridine 1‐oxide under the same conditions yielded only a reduction product, 3‐(α‐hydroxybenzyl)‐pyridine 1‐oxide, whereas 4‐benzoylpyridine 1‐oxide yielded only a redox product, 4‐(α‐hydroxy‐benzyl)pyridine. The redox reaction which is promoted by base occurs with an α‐hydroxybenzylpyridine 1‐oxide which results from a carbonyl reduction of the starting material. The benzoyl‐pyridine 1‐oxides reacted qualitatively the same with sodium ethoxide or isopropoxide as they did with ethanoiic sodium hydroxide, but they reacted differently with potassium t‐butoxide or aluminum isopropoxide. The cyano‐ and benzenesulfonyl‐pyridine 1‐oxides reacted with ethanolic sodium hydroxide to yield pyridinecarboxylic acids and 1‐hydroxypyridones, respectively.
Synthesis of a 2‐Methyl‐4‐sulfanilamido‐s‐triazine derivative
Authors: Kametani Tetsuji , Okui Kiyoshi , Koizumi Masuo 
Published: March 2009

AbstractAn attempt to obtain 2‐methyl‐4‐sulfanilamido‐s‐triazine (XXI) by condensation of 2‐amino‐4‐methyl‐s‐triazine (II) with p‐acetamidobenzenesulfonyl chloride (III) in pyridine and in benzene containing trimethylamine gave instead the unexpected products, guanidine N‐acetylsulfanilate (IV) (after hydrolysis) and N1,N1‐dimethylsulfanilamide (V), respectively. On the other hand, 2‐methyl‐4‐methylthio‐6‐sulfanilamido‐s‐triazine (XIX) was obtained from 4,6‐dimethylthio‐s‐triazine (XVII), but the reduction of XIX with Raney nickel in aqueous sodium hydroxide solution also gave an unexpected compound, sulfaguanidine (XX).
The preparation of 2‐Chloroformyl‐3‐phenylthiazolo[3.2‐a] pyridiniuin chlorides from cinnamic acids, pyridine and thionyl chloride
Authors: Wright W. B. , Brabander H. J. 
Published: March 2009

Abstract2‐Chloroformyl‐3‐phenylthiazolo[3.2‐a]pyridinium chlorides are among the by‐products obtained when 3‐chlorobenzo[b]thiophene‐2‐earbonyl chlorides are prepared by the reaction of cinnamic acids with thionyl chloride and pyridine.
Synthesis of 1,2,3‐triazole nucleosides via the acid‐catalyzed fusion procedure
Authors: Lehmkuhl Frank A. , Witkowski Joseph T. , Robins Roland K. 
Published: March 2009

AbstractThe acid‐catalyzed fusion of methyl 1,2,3‐triazole‐4‐carboxylate, 4‐cyano‐1,2,3‐triazole, and 4‐nitro‐1,2,3‐triazole with an acylated ribofuranose provided the corresponding 2‐β‐D‐ribo‐furanosyl‐4‐substituted‐1,2,3‐triazoles along with the isomeric 1‐β‐D‐ribofuranosyl‐4‐substituted‐1,2,3‐triazoles. The structures of these nucleosides were assigned on the basis of their nmr spectra. The synthesis of 2‐β‐D‐ribofuranosyl‐1,2,3‐triazole‐4‐carboxamide from both the corresponding methyl ester and cyano nucleosides is described. The cyano nucleosides were utilized to prepare 2‐β‐D‐ribofuranosyl‐1,2,3‐triazole‐4‐thiocarboxaḿide and 1‐β‐D‐ribofuranosyl‐1,2,3‐triazole‐4‐thiocarboxamide. Reduction of the 4‐nitro‐1,2,3‐triazole nucleosides provided 4‐amino‐2‐β‐D‐ribofuranosyl‐1,2,3‐triazole and the isomeric 4‐amino‐1‐β‐D‐ribofuranosyl‐1,2,3‐triazole. The acid‐catalyzed fusion procedure with 1,2,3‐triazole afforded 1‐β‐D‐ribofuranosyl‐1,2,3‐triazole and 2‐β‐D‐ribofuranosyl‐1,2,3‐triazole.
Derivatives of 10,11‐dihydro‐5H‐dibenzo[a,d]cycloheptene and related compounds VII. Improved syntheses of 11‐h‐benzo[5, 6] cyclohepta‐[1,2‐c] pyridin‐11‐one
Authors: Villani Frank J. , Wefer Elizabeth A. , Mann Thomas A. , Mayer Joseph , Peer Lydia , Levy Alfred S. 
Published: March 2009

AbstractAn improved synthesis of the title compound is described. The base catalyzed condensation of 4‐methylnicotinonitrile with benzaldehyde resulted in the isolation of trans‐4‐styrylnicotin‐amide (2a) in high yield. Hydrolysis to the acid and heating the acid 3a with polyphosphoric acid (ppa) gave the title compound 1a in good yields. Even higher yields of 1a were obtained in the presence of catalytic quantities of selenium. Also described are two other syntheses of the title compound as well as the preparation of a series of compounds related to 2a (Table I).
Synthesis of 4,5‐dihydro‐2,4‐benzoxazepin‐3( 1H)ones and 1,3,4,5‐tetrahydro‐2,4‐benzoxazepines
Authors: Pifferi Giorgio , Fontanella Luigi , Occelli Emilia , Monguzzi Riccardo 
Published: March 2009

Abstracto‐ Aminomethylbeiizyl alcohols (X) easily cyclize with phosgene in an aqueous alkaline medium to form 4,5‐dihydro‐2,4‐benzoxazepin‐3(1H)ones (IV) and with aldehydes in acidic conditions to yield 1,3,4,5‐tetrahydro‐2,4‐benzoxazepines (V). The characteristics and chemical behaviour of these new heterocyclic ring systems are reported.
Intramolecular diels‐alder reactions. IX. Syntheses of N‐benzylcyclolignan lactams
Authors: Klemm L. H. , Mcguire T. M. 
Published: March 2009

AbstractFour bis‐unsaturated N‐benzyl amides of the type where (C2) and (C2)' are variously trans‐CHCH and CC groups, were synthesized and refluxed in acetic anhydride. Three of them cyclized to form N‐benzylcyclolignan lactams by intramolecular Diels‐Alder processes. In one case [(C2)  CC, (C2)'  trans‐CHCH] the (C2) unit functioned as the dienophilic moiety.
Synthesis of azepinoquinazoloncs from 2‐methyl‐3‐(o‐tolyl)‐4‐quinazolone
Authors: Taylor John H. , Harrison Derek R. , Fried Ferdinand 
Published: March 2009

AbstractSome new azepinoquinazolones were synthesized from 2‐methyl‐3(o‐tolyl)‐4(3H)quinazolone (metliaqualone )as potential hypnotic agents. Methaqualone (I) reacted with dimethyl acetylene‐dicarboxylate (dmad) to give the azepinoquinazolone (II) which on treatment with PPA gave the pentacyclic ketone (V). Subsequent sodium borohydride reduction of the ketone (V) gave the fused azepine (VIa). Reaction of the azepinoquinazolone (II) with formic acid resulted in cleavage of the quinazolone nucleus to give the azepine (VIII). None of the compounds synthesized exhibited significant hypnotic activity.
The reactions of some pyranylideneiminium salts with amines. Part 1
Authors: Van Allan J. A. , Reynolds G. A. , Maier D. P. , Chang S. Chie 
Published: March 2009

AbstractThe iminium salt, N,N‐dimethyl‐N‐[2‐(2,6‐diphenyl‐4H‐pyran‐4‐ylidene)ethylidene]iminium perolilorate (1), reacts with secondary amines, such as piperidine, by exchanging the dimethyl‐amino function for a piperidine. Primary amines react with 1 to give 1‐alkyl‐2‐phenyl‐4‐phenacylidene‐1,4‐dihydropyridines. The bisiminium salt, N,N,N',N' ‐tetramethyI‐N,N'‐[2‐(2,6‐diphenyl‐4H‐pyran‐4‐ylidene)‐1,3‐propanediylidene]bis(iminium perchlorate) (2), reacts with ammonia to give 3,6‐diphenylcopyrine and with primary amines to give the corresponding N,N' ‐dialkyl quaternary copyrines. The salt 2 reacts with secondary amines with exchange of the dimethylamino groups of 2 by the secondary arnine and addition of the amine at the 2‐position of the pyran ring.
The reactions of some pyraiiylideneiminium salts with amines. II
Authors: Van Allan J. A. , Chang S. Chie , Reynolds G. A. 
Published: March 2009

AbstractThe iminium salt, N,N‐dimethyl‐N‐[2‐(2‐phenyl‐4H‐l‐benzopyran‐4‐ylidene)ethylidene] imin‐ium perchlorate (3), reacts with secondary amines by exchanging the dimethylimino group for the added amine. Primary amines also reacted with 3 in the same manner. The bis iminium salts, N,N,N',N'‐tetramethyl‐N,N'‐[2‐(2‐phenyl‐4H‐l‐benzopyran‐4‐ylidene)‐1,3‐propanediylidene]‐bis(immium perclilorate) (4) and the corresponding thiapyran derivative (5), react with ammonia to give 5‐dimethylamino‐2‐phenyl‐5H‐1‐benzopyrano[3,4‐c]pyridine (10) and the thia analog 11. The reactions of 4 and 5 with primary amines give 3‐alkyl‐5‐dimethylamino‐2‐phenyl‐5H‐l‐beiizopyrano[3,4‐c]pyridinium perclilorate salts or the corresponding thiapyrano compounds. Compounds 4 and 5 react with secondary amines by exchanging the dimethylimino groups with the secondary amine and addition of the amine at the 2‐position of the pyran or thiapyran ring.
Synthesis of phenylated phthalimides. The diels‐alder reaction of tetraphenylcyclopentadienone with maleimides
Authors: Harris Frank W. , Norris Steve O. 
Published: March 2009

AbstractA series of phenylated dihydrophthalimides has been synthesized by the Diels‐Alder reaction of tetraphenylcyclopentadienone with maleimide, N‐phenylmaleimide, and N,N'‐o‐, ‐m‐, and ‐p‐phenylenedimaleimide. Subsequent dehydrogenation of these compounds yielded the corresponding phenylated phthalimides. These phthalimides were also obtained in one step when the initial reactions were carried out in refluxing nitrobenzene.
Synthesis of 3‐aryl‐7‐nitro‐3,4‐dihydroisocoumarins from 4‐nitrohomophthalic acid
Authors: Barry Roger D. , Balding Richard A. 
Published: March 2009

Abstract4‐Nitrohomophthalic acid reacts with aromatic aldehydes in the presence of piperidine to yield 3‐aryl‐7‐nitro‐3,4‐dihydroisocoumarins. Under the same conditions, homophthalic acid yields stilbene‐α,2‐dicarboxylic acids.
Organosilicon compounds XVII. Introduction of the dialkyl phosphonate and dialkyl thiophosphonate moieties on an organosilicon substituted heterocyclic system
Authors: Thames Shelby F. , Edwards Laroy H. , Jacobs Thornton N. , Grube Paul L. , Pinkerton Frank H. 
Published: March 2009

AbstractA number of new dialkyl 2‐(5‐trisubstitutedsilyl)thienylphosphonates and thiophosphonates as well as dialkyl 2‐(5‐trisubstitutedsilyl)furylphosphonates and thiophosphonates were prepared via reaction of the 5‐(trisubstitutedsilyl)‐2‐lithiothiophenes and furans with dialkyl chloro‐phosphate and dialkyl chlorothiophosphate. Moreover, some diethyl 2‐[5‐(trisubstitutedsiIyl)‐2‐thienyl] ethyl thiophosphates are reported.
Studies on the syntheses of heterocyclic compounds. CDXCI pyrimidine derivatives V. Abnormal condensation products of 4‐amino‐6‐chloro‐2‐methoxypyrimidine with p‐nitrobenzenesulfonyl chloride
Authors: Okui Kiyoshi , Ito Kiyohiko , Koizumi Masuo , Fukumoto Keiichiro , Kametani Tetsuji 
Published: March 2009

AbstractCondensation of 4‐amino‐6‐chloro‐2‐methoxypyrimidine (I) with p‐nitrobenzenesulfonyl chloride (II) gave, in addition to 6‐chloro‐2‐methoxy‐4‐(p‐nitrobenzenesulfonamido)pyrimidine (III), two abnormal by‐products, the structures of which were assigned as 1‐[2‐methoxy‐4‐(p‐nitrobenzenesulfonamido)pyrimidine‐6‐yl]pyridinium N,N‐betaine (IV) and N‐(p‐nitrobenzene‐sulfonyl)‐β‐ureido‐β‐pyridinium acrylamide N,N‐betaine (V).
Photoelimination reactions of N‐heteroaromatic compounds
Authors: Stermitz F. R. , Huang W. H. , Blythin D. J. , Hoeft A. , Kim D. K. , O'Donnell C. M. 
Published: March 2009

AbstractN‐Heteroaromatic compounds substituted with a side chain next to the nitrogen and bearing a hydrogen gamma to the ring, undergo a photoelimination reaction to yield the methyl‐substituted heterocycle and an alkene (if the gamma hydrogen is on a side chain carbon) or an aldehyde (if the gamma hydrogen is on a side chain oxygen). The reaction has been shown to occur with substituted isoquinolines, plienanthridines, pyridines and pyrazines.
Steroids. Synthesis of 1,4‐oxazine derivatives of estrone
Authors: Roy Sunil K. 
Published: March 2009

AbstractEstratrieno[3,2‐b]‐1,4‐oxazin‐3′‐one (V) and estratrieno[3,4‐b]‐1,4‐oxazin‐3′‐one (VI) have been converted to the corresponding amidines. The tautomerism of the thiones and the amidines are discussed.
Synthetic studies on pyrroloquinolines. II. Studies on the syntheses and chemical properties of 1H‐pyrrolo[2,3‐b] quinolmes
Authors: Tanaka Tadasu , Iwakuma Takeo , Wagatsuma Mitsuyoshi , Iijima Ikuo 
Published: March 2009

AbstractThis paper describes the syntheses and the properties of 1H‐pyrrolo[2,3‐6]quinolines derived from 2,3‐dihydrofuro[3,2‐c]quinolines or 3‐(β‐chloroethyl)‐2,4‐dichloroquinolines. The discrepancy on the physical data of 1H‐pyrrolo[2,3‐b]quinoline between our product and Perkin's previously reported product is also discussed.
Studies on the syntheses of heterocyclic compounds. Part CDXCVII. Total syntheses of (±)‐cryptaustoline and (±)‐thaliporphine by the benzyne reaction
Authors: Kametani Tetsuji , Fukumoto Keiichiro , Nakano Takuo 
Published: March 2009

AbstractThe indisputable benzyne reaction of 1‐(5‐bromo‐3,4‐dimethoxybenzyl)‐1,2,3,4‐tetrahydro‐7‐hydroxy‐6‐metlioxy‐2‐methylisoquinoline (II) with sodium amide in liquid ammonia afforded the following compounds, (±)‐cryptaustoline iodide (VI), (±)‐thaliporphine (VIII), 1 ‐(3,4‐dimeth‐oxybenzyl)‐ (III), and 1 ‐(2‐amino‐4,5‐dimethoxybenzyl)‐l,2,3,4‐tetrahydro‐7‐hydroxy‐6‐meth‐oxy‐2‐methylisoquinoline (IV).
Synthesis of diazasteroids II. Synthesis of 8,11‐diaza‐2,3‐dimethoxygona‐1, 3,5 (10), 9 (11)‐tetraene
Authors: Nagata Masanori , Goi Masami , Matoba Katsuhide , Yamazaki Takao , Castle Raymond N. 
Published: March 2009

AbstractHomoveratrylamine was condensed with 1‐cyanocyclopentene to afford the corresponding 2‐cyano‐N‐(3,4‐dimethoxyphenethyl)cyclopentylamine (III), which was ethoxycarbonylated with ethyl chlorocarbonate to give the trans‐urethan (IVt) (major product) and the cis‐urethan (IVc) which could be separated through a silica gel column. The cis‐urethan was converted to the trans‐urethan by the action of a catalytic amount of sodium ethoxide. Based upon general considerations of nucleophilic addition such as the Michael type reaction, the physical data obtained, and the difference in ease of cyclization of the 2‐aminomethyl‐N‐ethoxycarbonyl‐. N‐homoveratrylcyclopentylamines (Vt and Vc) to the corresponding cyclic ureas (Vlt and VIc), it was concluded that the major product was the trans and the minor the cis isomer.The cyclized compounds, Vlt and VIc, were subsequently submitted to the Bischler‐Napieralski reaction furnishing the corresponding isoquinoline derivatives respectively. Thus the authors established a skeletal synthesis of the title compound, a 8,11‐diazasteroid, and its stereochemical configuration at the C/D ring juncture was elucidated.
9‐Hydroxy‐2‐methyl‐4H‐pyrido[1,2‐α] pyrimidin‐4‐one and its derivatives
Authors: Yale Harry L. , Sheehan John T. 
Published: March 2009

Abstract2‐Amino‐3‐(o‐bromobenzyloxy)pyridine (1) and ethyl acetoacetate gave 9‐(o‐bromobenzyl‐oxy)‐2‐methyl‐4H‐pyrido[1,2‐α]pyrimidin‐4‐one (2) in 2% yield. When 1 and methyl β‐amino‐crotonate (3) were reacted, benzyl ether cleavage occurred and the products were 9‐hydroxy‐2‐methyl‐4H‐pyrido[1,2‐α]pyrimidin‐4‐one (4) and its ammonium salt (5). These observations led to an alternative synthesis in which 2‐amino‐3‐pyridinol (6) and either 3 or methyl acetoacetate, (8) in diethylbenzene at 185° gave 4 in 86 and 87% yields, respectively, and the anion of 4 and o‐bromobenzyl bromide gave 2 in 61% yield. Even in diethylbenzene at 185°, 1 and 8 gave only trace amounts of 2. Thus, o‐bromobenzylation of the 3‐hydroxyl group in 6 markedly decreased the reactivity of the amino group in 6 toward reactions with acetoacetic esters.
Studies on the bromination of pyrimidine. A facile synthesis of 5‐bromopyrimidine
Authors: Kress Thomas J. , Moore Larry L. 
Published: March 2009

AbstractThree methods for hromination of pyrimidine were investigated: (a) the bromination of pyrimidine hydrochloride in aromatic solvents, (b) the vapor phase bromination of pyrimidine, and (c) the pyrolysis of pyrimidine hydrochloride perbromide. The addition of bromine to a slurry of pyrimidine hydrochloride in nitrobenzene proved to be superior and afforded excellent yields of 5‐bromopyrimidine.