bluuebunny/crossref_metadata_2025_split huggingface dataset:
2,4,8,10‐Tetraoxa‐3,9‐diphosphaspiro[5.5]undecane‐3,9‐disulfide and Some Derived Compounds
Authors: Rätz Rudi , Bliss Arthur D. 
Published: March 2009

Abstract2,4,8,10‐Tetraoxa‐3,9‐diphosphaspiro[5.5]undecane‐3,9‐disulfide (I) has been prepared by the treatment of 3, 9‐dichloro‐2,4,8,10‐tetraoxa‐3,9‐diphosphaspiro[5.5]undecane (II) with hydrogen sulfide. The reactions of I with thiocyanates to give esters of 3,9‐dimercapto‐2,4,8,10‐tetraoxa‐3,9‐diphosphaspiro[5.5]undecane‐3, 9‐disulfide (III) and with isocyanates and isothiocyanates to give P‐carbamoyl and thiocarbamoyl derivatives of I were investigated. I was also found to condense with chloral to produce an α‐hydroxy‐thiophosphonate (XXVIII), but similar reactions with other aldehydes failed to yield analogous products.
Thiazolo [3,2‐a] pyridinium salts
Authors: Bradsher C. K. , Lohr D. F. 
Published: March 2009

AbstractThe sulfides formed by the reaction of α‐halo ketones or α‐halo acetals with 2‐mercaptopyridine may be cyclized in good yield to form thiazolo[3, 2‐a]pyridinium salts. The presence of chloro or nitro substituents on the pyridine ring does not interfere with the synthesis. Nitration of 3‐methylthiazolo[3, 2‐a]pyridinium perchlorate has been found to occur at position 8.
Ten‐π ‐ electron nitrogen heterocyclic compounds. VIII. Semi‐empirical calculations of chemical‐shifts of ring‐protons and of methyl‐protons
Authors: Paudler William W. , Kuder James E. 
Published: March 2009

AbstractThe chemical‐shifts of the ring protons and of the methyl protons of some unsub‐stituted and some methylpolyazanidenes have been calculated by a semi‐empirical method utilizing charge‐densities obtained from HMO calculations. The success of this method lies in the choice of the reference compound, pyrrocoline.
Benzo[b]thiophene derivatives. VIII. Benzo[b]thiophene‐3‐earboxaldehyde and derivatives
Authors: Campaigne E. , Neiss E. S. 
Published: March 2009

AbstractA procedure for the preparation of benzo[b]thiophene‐3‐carboxaldehyde from 3‐methyl‐benzo[b]thiophene is reported. This aldehyde behaves as a typical reactive aromatic aldehyde with respect to oxidation, reduction, the mixed Cannizzaro reaction, reductive amination and acyloin and other condensation reactions.
Tautomeric structure of 1‐Oxy‐2‐phenylbenzimidazole
Authors: Stacy Gardner W. , Wollner Thomas E. , Oakes Thomas R. 
Published: March 2009

AbstractThe synthesis of 3‐methyl‐2‐phenylbenzimidazole‐1‐oxide (VIII) has been accomplished. Consequently, it has been possible to establish the tautomeric structure of I as 1‐hydroxy‐2‐phenylbenzimidazole (Ia). Contrary to recent observations on the parent 1‐oxybenzimidazole (IV), I shows no tendency to exist as an N‐oxide (Ib) in aqueous solution.
Physical and chemical properties of hydroxyflavones. V. Deuteroxyflavones from acetoxyflavones by imidazole‐catalyzed deacetylation
Authors: Looker J. H. , Kagal S. A. , Edman J. R. 
Published: March 2009

AbstractA recently described procedure for imidazole‐catalyzed deacetylation of acetoxyflavones has been modified by effecting hydrolysis in a mixture of deuterium oxide and deuterioethanol (C2H5OD), or in deuterium oxide and deuteriomethanol (CH3OD). Application of the new procedure to monoacetoxyflavones has resulted in the monodeuteroxyflavone. 5‐Deuteroxyflavone has been obtained also by hydrolysis of a rubidium salt in deuterium oxide. Imidazole‐catalyzed hydrolysis of four diacetoxyflavones in a mixture of deuteriomethanol and deuterium oxide is described. Infrared spectral data are presented for the deuteration products, with emphasis on OD stretching and vibrational modes. Comparison of spectra of appropriate monohydroxyflavones and monodeuteroxyflavones permits assignment of δ (OH) bands in four hydroxyflavone spectra.
The reaction of phosphorus pentasulfide with halogen‐substituted nitrogen heterocycles
Authors: Castle Raymond N. , Kaji Kenji , Gerhardf G. Anne , Guither William D. , Weber Celia , Malm Miriam P. , Shoup Regitze R. , Rhoads William D. 
Published: March 2009

AbstractThe novel nucleophilic displacement of halogen by sulfur, by the use of phosphorus pentasulfide in boiling pyridine has been shown to be a general reaction for activated halogen nitrogen heterocycles.
Reaction of inorganic cyanates with halides. II. Reactions of chlorohydrins
Authors: Phillips Brian L. , Argabright Perry A. 
Published: March 2009

AbstractThe reaction of ethylene and trimethylene chlorohydrins with cyanate ion in anhydrous dimethylformamide (DMF) forms 2‐oxazolidinone and tetrahydro‐2H‐1, 3‐oxazin‐2‐one, respectively. These are the major products over a wide concentration range, and at initial chlorohydrin concentration of 1 M and lower, the yields are high enough to make the reaction useful for synthesis of oxazine and oxazolidine derivatives. The corresponding reaction with tetramethylene chlorohydrin gave tetrahydrofuran as the major product with the by‐products being polymeric. Pentamethylene and hexamethylene chlorohydrins yield linear polyurethanes when allowed to react with cyanate in DMF. Examination of the relative rates of reaction of these chlorohydrins indicate that the mechanism by which urethanes are formed (both cyclic and polymeric) is an SN2 displacement of chloride by cyanate ion to give an isocyanate intermediate which then reacts with an alcohol group to form urethane.
A convenient preparation of indoline
Authors: Dolby Lloyd J. , Gribble Gordon W. 
Published: March 2009

AbstractAn efficient method for chemically reducing indole to indoline using zinc dust and 85% phosphoric acid is described. 2, 3‐Dimethylindole, 1,2,3, 4‐tetrahydrocarbazole and N‐methyl‐l,2,3,4‐tetrahydrocarbazole are also reduced to the corresponding dihydroindoles in somewhat lower yields. Unlike earlier acid‐metal reductions of indole little or no polymerization is observed.
s‐Triazines. I. Linear, sulfur bridged‐s‐triazine oligomers
Authors: Loughran Gerard A. , Ehlers Gerhard F. L. , Burkett Jerald L. 
Published: March 2009

AbstractA number of new thioether and disulfide oligomers of s‐triazine have been prepared and identified.The reactions between 2,4‐diphenyl‐s‐triazine‐6‐thiol and chloro substituted‐s‐triazines are described. A suggested mechanism for the formation of 2,2′‐thiobis‐(4,6‐diphenyl‐s‐triazine) from 2,4‐diphenyl‐s‐triazine‐6‐thiol is discussed.
s‐Triazines. II. The synthesis of some new cyclopoly‐s‐triazinylene thioethers and disulfides
Authors: Loughran Gerard A. , Ehlers Gerhard F. L. , Burkett Jerald L. 
Published: March 2009

AbstractA number of new cyclopoly‐s‐triazinylene thioethers and disulfides have been prepared in dilute solution. Their structures and methods of formation are discussed. A thermo‐gravimetric analysis of cyclopoly‐2‐phenyl‐s‐triazinylene‐4,6‐monosulfide is included.
The synthesis of some 4,4′‐disubstituted‐2,2′‐biquinolines
Authors: Case Francis H. , Lesser Joseph M. 
Published: March 2009

Abstract2,2′‐Biquinoline dioxide and 4,4′‐dichloro‐2,2′‐biquinoline have been used for the preparation of the following 4,4′‐disubstituted‐2,2′‐biquinolines: dimethoxy, diethoxy, dihydroxy, dipiperidino, dipyrrolidino, dibromo, diphenoxy, dithiophenoxy, di(p‐chloro‐phenoxy), di(p‐bromophenoxy), di(p‐fluorophenoxy), di(β‐naphthoxy) and the dinitro dioxide. Molar extinction coefficients have been determined for several of the copper (I) complexes of these compounds.
Some novel cyclizations of propiophenones with chlorosulfonic acid
Authors: Meyer Robert F. 
Published: March 2009

AbstractThe reaction of chlorosulfonie acid with propiophenones was found to give the 3‐chloro‐2‐methylbenzothiophene‐1, 1‐dioxides (I) and (VIII); reaction of Mannich bases of aceto‐phenone, with chlorosulfonie acid, gave the corresponding 3‐chloro‐2‐substituted amino‐methylbenzothiophene‐1,1‐dioxides (IX) and (X). The above structures were established by reaction with various nucleophiles and by hydrogenation. o‐Hydroxypropiophenones, under the above conditions, are cyclized to the cyclic sulfones (XII) and (XIII). Ring opening with pyrrolidine gave the corresponding phenolic sulfonamides (XIV) and (XV).
Preparation and thermal decomposition of certain. Substituted bis‐(thenoyl) peroxides
Authors: Schuetz Robert D. , Gruen Fred M. , Byrne Delos R. , Brennan Richard L. 
Published: March 2009

AbstractThe effect of various substituents on the rates of thermal decomposition of substituted bis‐(thenoyl) peroxides has been investigated. Nine unreported peroxides were prepared, including derivatives of 2‐ and 3‐thenoic acids. The thermal decomposition rates of these peroxides were examined, in the presence of styrene as a free radical scavenger. First order kinetics were observed in all cases studied. In general it was found that electron releasing substituents increase, while electron withdrawing groups decrease, the decomposition rate; the only exception being bis‐(5‐nitro‐3‐thenoyl) peroxide. Entropies and energies of activation were determined and found to be linearly related for the peroxides studied.
s‐Triazolo[4,3‐b]pyridazines and imidazo[4,5‐c]pyridazines
Authors: Kuraishi Tsukasa , Castle Raymond N. 
Published: March 2009

Abstract8‐Amino‐s‐triazolo[4, 3‐b]pyridazine (I), an adenine analog has been prepared by two different routes. Likewise 8‐amino‐3‐phenyl‐s‐triazolo[4,3‐b]pyridazine (V) has been prepared. Both of these compounds have been prepared utilizing 3,4,5‐trichloropyridazine and 3,4,6‐trichloropyridazine as the starting materials thus interrelating the 3,4,5‐and the 3,4,6‐series. A variety of other transformations have been carried out.
Ten π ‐electron nitrogen heterocyclic compounds:X the syntheses and structure determinations of some 1,2,4‐triazolopyrimidines
Authors: Paudler William W. , Helmick Larry S. 
Published: March 2009

AbstractIt has been shown that the reaction of 2‐hydrazinopyrimidines with ethyl orthoesters yields 1,2,4 ‐triazolo[4,3 ‐a]pyrimidines as well as 1,2,4‐triazolo[1,5‐a]pyrimidines. The structures of the parent compounds and of some methyl derivatives have been established by NMR spectroscopy.
The synthesis of 1‐substituted‐2‐(β‐dimethylaminoethyl)benzimidazoles
Authors: Ganellin C. R. , Ridley H. F. , Spickett R. G. W. 
Published: March 2009

Abstract2‐(β‐Dimethylaminoethyl)benzimidazoles have been prepared by the reduction of the corresponding 2‐benzimidazole‐N,N‐dimethylacetamides. Condensation of ethyl cyanoacetate with N‐benzyl or phenyl‐o‐phenylenediamines led to N‐cyanoacetyl‐N'‐substituted‐o‐phenylenediamines, the structure of which were assigned from u.v. and n.m.r. data. An improved synthesis of benzimidazole ‐ 2 ‐ acetic acid derivatives, from substituted ethyl acetimidates and o‐phenylenediamines, is described. Dimerisation of 1‐phenyl‐benzimidazole occurs in the presence of phenyllithium.
Derivatives of the thiazolo[2,3‐a]isoquinolinium system
Authors: Andrew H. F. , Bradsher C. K. 
Published: March 2009

AbstractThe ketosulfides (IV) formed by the reaction of α‐bromoketones with 2α‐thiohomo‐phthalimide (II) have been cyclized to form hydrogen‐bonded, dimeric hemiperchlorates (V). Alternative products from the cyclization, 2‐[2′‐(carboxymethyl)phenyl]thiazoles (VII), may be cyclized with acetic anhydride to O‐betaines (VI). The same betaines are obtained from the hemiperchlorates (V) by deprotonation. The ketosulfide hydrobromides (XIII) from α‐bromoketones and 1‐thio‐3, 4‐dihydroisocarbostyril (XII) give 5,6‐dihydro‐thiazolo[2,3‐a]isoquinolinium salts (XV) on cyclization.
Synthesis of 6‐substituted pyrimidines by the wittig reaction. II . Via 2‐acetamido‐4‐hydroxy‐5‐phenylbutylpyrimidine‐6‐carboxaldehyde
Authors: Baker B. R. , Jordaan Johannes H. 
Published: March 2009

AbstractWittig condensations of both stabilized and unstabilized ylides were successfully achieved with 2‐acetamido‐4‐hydroxy‐5‐phenylbutylpyrimidine‐6‐carboxaldehyde (XI); functionalized Wittig reagents derived from dichloroacetone, ethyl 4‐iodobutyrate, 4‐bromobutyronitrile, phenylpropyl bromide, 3‐bromopropylphthalimide, p ‐ nitrobenzyl bromide, and p‐nitrocinnamyl bromide were used. The resultant 6‐substituted pyrimidines could be further transformed by reduction of the 6‐side‐chain double bond. Successful Wittig reactions were achieved with XI where the corresponding 2‐amino‐4‐hydroxy‐5‐phenylbutylpyrimidine‐6‐carboxaldehyde (X) with its less electrophilic aldehyde group failed to give isolable yields of condensation products.
Cyclic imides III. A study of the hydroxy‐ and methoxyphthalimidoacetic acids and the methyl methoxyphthalimidoacetates
Authors: Caswell Lyman R. , Atkinson Patsey C. 
Published: March 2009

AbstractThe hydroxy‐ and methoxyphthalimidoacetic acids and the methyl methoxyphthalimidoacetates have been synthesized. The ultraviolet absorption spectra of these compounds in 95% ethanol, aqueous acid, and aqueous base are discussed. Structures are suggested for the hydroxy‐ and methoxyphthalamate ions which are formed in basic solution. The Gabriel‐Colman rearrangements of methyl 3‐ and 4 ‐ methoxyphthalimidoacetate give, respectively, 8‐methoxy‐4‐hydroxy‐3 ‐ carbomethoxy‐1(2H)‐isoquinolone (VII) and 6‐methoxy‐4‐hydroxy‐3‐carbomethoxy‐1(2H)‐isoquinolone (VIII).
5α‐androstano [3,2‐b]pyridines, 5α‐androstano[17,16‐b]pyridines and androst‐4 and 5‐eno[17,16‐b]pyridines
Authors: Miller Theodore C. 
Published: March 2009

AbstractA new synthesis of 5α‐androstano[3,2‐b]pyridin‐17β‐ol acetate (VIa) and 17‐methyl‐5α‐androstano[3,2‐b]pyridin‐17β‐ol (VIb), first reported by Shimizu, Ohta, Ueno, and Takegoshi, was achieved. The analogous 5α ‐ androstano[17,16‐b]pyridin‐3β‐ol (XII), 5α‐androstano[17,16‐b]pyridin‐3‐one (XIVa), and androst‐4‐eno[17,16‐b]pyridin‐3‐one (XIVb) were also prepared. An illustration of the method follows. Condensation of 3β‐hydroxy‐5α‐androstan‐17‐one (VIIa) with 3‐(2‐furyl)acrolein afforded 16‐[3‐(2‐furyl)‐2‐propenylidene]‐3β‐hydroxy‐5α‐androstan‐17‐one (VIIIa), the oxime (IXa) of which was thermally cyclized to 5α‐androstano[17,16‐b]‐6′‐(2‐furyl)pyridin‐3β‐ol (Xa). 3β‐Hydroxy‐5α‐androstano[17,16‐b]pyridine‐6′‐carboxylic acid (XI) was obtained by ozonolysis of Xa. Thermal decarboxylation of XI gave XII. Cinnamaldehyde was used in place of 3‐(2‐furyl)acrolein to give the corresponding phenylpyridines.
The synthesis of some phenothiazinyl ketones and their derivatives
Authors: Kadaba Pankaja K. 
Published: March 2009

AbstractThe synthesis of a number of 2‐chloro‐8‐acylphenothiazines via the Friedel‐Crafts reaction has been reported. A series of dialkylaminoalkyl ketones have been derived from 2‐chloroacetyl‐ and 2‐chloro‐8‐chloroacetylphenothiazines. A number of dialkylaminoalkyl esters of 2‐phenothiazinecarboxylic acid have also been synthesized.
The formation of lactams of N‐(2‐amino)benzoylamino acids
Authors: Hoffmann Eliahu , Jagnicinski Boris 
Published: March 2009

AbstractN‐(2‐Nitro)benzoylamino acids were prepared by 2‐nitrobenzoylation of amino acids via the mixed ethylcarbonic anhydride procedure. They were reduced catalytically to N‐(2‐amino)benzoylamino acids which underwent cyclization to the corresponding lactams under a variety of conditions. The use of this reaction sequence for stepwise degradation of peptides seems possible.
Synthetic experiments related to the indole alkaloids V. mercuric acetate oxidation of 2‐[2‐(3‐indolyl)ethyl]‐1,2,3,4‐tetrahydroisoquinolines and the formation of benz[a]indolo[3,2‐h]quinolizine derivatives
Authors: Potts K. T. , Roy S. K. , Liljegren D. R. 
Published: March 2009

AbstractOxidation of 2‐[2‐(3‐indolyl)ethyl]‐1,2,3,4‐tetrahydroisoquinoline (I) with mercuric acetate gave 5,6,8,9,14,14b‐hexahydrobenz[a]indolo[3,2‐h]quinolizine (IV) and 8,9‐dihydro‐14H‐benz[a]indolo[3,2‐h]quinolizin‐7‐ium iodide (VI), as well as starting material. The base (IV) was oxidized with iodine and potassium acetate to VI and on Palladium carbon ‐ maleic acid dehydrogenation yielded 5,6‐dihydro‐14H‐benz[a]indolo[3,2‐h]‐quinolizin‐7‐ium iodide (IX), and 14H‐benz[a]indolo[3,2‐h]quinolizin‐7‐ium iodide (X). Heating the iodide (VI) with Palladium‐carbon brought about an irreversible rearrangement to VII and both these salts with base yielded the red anhydro base 8, 9‐dihydrobenz[a]indolo[3,2‐h]quinolizine (VIII). This base was also obtained from IV by oxidation in air.The corresponding 8, 9‐dehydroanhydro base (XI), benz[a]indolo[3,2‐h]quinolizine, was readily obtained from X and alkali. The quinolizinium salts (VI), (VII), and (IX), on catalytic, zinc dust and acetic acid, or sodium borohydride reduction, regenerated the base (IV). Selenium degradation of IV gave, among other products, 1‐(2‐ethylphenyl)‐β‐carboline. An analogous series of products was obtained with the 6, 7‐dimethoxy derivative of I. Various other aspects of these and related transformations are described.
Crystal and molecular structure of 6‐(p‐iodobenzenesulfonyl)‐3‐oxa‐6‐azabicyclo[3.1.0]hexane
Authors: Trefonas L. M. , Sato Tatsuo 
Published: March 2009

AbstractThe crystal and molecular structure of 6‐(p‐iodobenzenesulfonyl)‐3‐oxa‐6‐azabicyclo‐[3.1.0]hexane has been determined by a three‐dimensional single‐crystal x‐ray diffraction study. The compound crystallizes in the monoclinic space group C2/c with cell dimensions, a = 19.76, b = 8.17, c = 15.72 ± 0.003 Å and β = 109.3° ± 0.2°. The aziridine ring is fused cis to the oxa‐cyclopentane ring with fusion angles of 112°. The bicyclic system is in the boat conformation with the p‐iodobenzenesulfonate group at an angle of 98.0° to it. The conformation of the ring system is discussed. A final value of R = 0.099 was obtained for the 1107 independent reflections.
The synthesis of 1,4,5‐trialkyl‐2‐pyrazolines from monoalkylhydrazines and aliphatic aldehydes
Authors: Rabjohn Norman , Havens H. R. , Rutter J. L. 
Published: March 2009

AbstractIt has been found that the thermal decomposition of heptanal methylhydrazone affords 5‐hexyl‐1‐methyl‐4‐pentyl‐2‐pyrazoline (I), in addition to heptanenitrile and methylamine. The formation of I suggests the synthesis of 1,4, 5‐trialkyl‐2‐pyrazolines from monoalkylhydrazines and aliphatic aldehydes. A number of these compounds have been prepared in good yields by this method, or through the related hydrazones, and some of their physical and chemical properties have been studied.
Stereochemical studies on 7‐substituted 8‐oxa‐1‐azabicyclo[4.3.0]nonanes
Authors: Crabb T. A. , Newton R. F. 
Published: March 2009

AbstractA set of racemic 7‐substituted 8‐oxa‐1‐azabicyclo[4.3.0]nonanes have been prepared and configurational and conformational assignments made on the basis of the value of the geminal coupling constants for the C9 methylene protons. The limitations of the Bohlmann infrared criterion in studying the conformations of these compounds is discussed.
Synthesis and nucleophilic displacement reactions of fluoropyrazine and 2‐fluoroquinoxaline
Authors: Rutner Herman , Spoerri Paul E. 
Published: March 2009

AbstractAn improved method for the preparation of fluoropyrazine (I) by halogen exchange and a synthesis of 2‐fluoroquinoxaline (II) by a Balz‐Schiemann reaction are presented. Compound I hydrolyzes slowly in 0.01N sodium hydroxide, rapidly in 1.07N sodium hydroxide at 26.00°. Compound II hydrolyzes 240 times faster than I in 0.01N sodium hydroxide at 26.00°. Hydrolysis of I in 6N hydrochloric acid at room temperature is slow. Compound I underwent nucleophilic reactions with formation of hydroxy, amino, methylamino, piperidino, benzylamino and anilinopyrazines. Pyrazinesulfonic acid was obtained from I and sodium sulfite and tetrazolo[1, 5‐a]pyrazine (IV), a novel ring system, from I and sodium azide.
8‐Arylpurines and their ultraviolet absorption spectra
Authors: Fu S.‐C. J. , Chinoporos E. 
Published: March 2009

AbstractDehydrocyclization of 4‐amino‐5‐arylamidopyrimidines in polyphosphoric acid to 8‐arylpurines was further investigated. Various other 8‐arylpurines were synthesized by this new procedure in high purity and yield. The ultraviolet absorption spectra of the arylpurines and the corresponding acylamidopyrimidines were measured at pH 1, 7, and 13 at 0.1 molar ionic strength. The spectra of the purines resemble those of the corresponding acylamidopyrimidines and, to a lesser extent, the corresponding 4,5‐diaminopyrimidines. The bathochromic shifts caused by different substituting groups in monosubstituted purines, in general, parallel the inductive effect of the substituting groups. The hyperchromicity and the inductive constant of the substituting groups assume a linear relationship, for substitution at either the 2 or 6 position. These changes in the wave length of maximum absorption and in the molar extinction coefficient caused by 2, 6 and 8 substitutions of the purines reported here are in agreement with previous studies by Mason.
5‐Amino‐5‐deoxyribose derivatives. Synthesis and use in the preparation of “Reversed” Nucleosides
Authors: Leonard Nelson J. , Carraway Kermit L. 
Published: March 2009

AbstractMethyl 5‐amino‐5‐deoxy‐2,3‐O‐isopropylidene‐β‐D‐ribofuranoside (III) has been synthesized and used as an intermediate in the preparation of the kinetin analog, methyl 5‐deoxy‐5‐(purin‐6‐yl)amino‐β‐D‐ribofuranoside (X). The related 1‐substituted adenine, methyl 5‐ (6‐aminopurin‐1‐yl)‐5‐deoxy‐2,3‐O‐isopropylidene‐β‐D‐ribofuranoside (XIII), was prepared by cyclization of 1‐benzyl‐5‐cyano‐4‐ethoxymethyleneaminoimidazole (XI) with III and subsequent debenzylation with sodium in liquid ammonia. The structures and stereochemistry of these compounds were established by a combination of ultraviolet and nuclear magnetic resonance spectroscopy.
Synthetic porphyrins. I. Synthesis and spectra of some para‐substituted meso ‐ Tetraphenylporphines
Authors: Datta‐Gupta N. , Bardos T. J. 
Published: March 2009

AbstractA series of derivatives of meso‐tetraphenylporphine, with neutral, acidic and basic functional groups, has been prepared. Several of these compounds were synthesized directly via the Rothemund reaction, under a variety of conditions to obtain optimal yields; others were prepared by interconversions of various functional groups. Drastic reaction conditions employed for hydrolysis, alcoholysis, or lithium aluminum hydride reduction did not affect the porphine ring system. The two amino derivatives showed anomalous spectra in the visible range.
A facile synthesis of piperazines from primary amines
Authors: Henry David W. 
Published: March 2009

AbstractA general procedure is described for converting primary amines to N‐substituted piperazines. Reaction of an amine with an N‐substituted iminodiacetic acid anhydride (V) yields an iminodiacetic acid monoamide (VI) which closes to a 2,6‐piperazinedione (VII) upon treatment with acetic anhydride. The diones are reduced to piperazines with borane‐THF. Fourteen examples of this process, using twelve aliphatic or aromatic amines and three iminodiacetic acids, are presented. Yields of piperazines, based upon starting amine, ranged from 21 to 52%. The procedure is rapid and no purification problems were encountered. Alternate methods for preparing the 2,6‐piperazinedione intermediates are discussed.
The synthesis of pyrazino[2,3‐d]pyridazine and some of its derivatives
Authors: Patel Natu R. , Castle Raymond N. 
Published: March 2009

AbstractPyrazino[2,3‐d]pyridazine (I) was synthesized by two different routes. 5, 8‐Dihydroxy‐pyrazino[2, 3‐d]pyridazine (IV) was converted to 5, 8‐dichloropyrazino[2, 3‐d]pyridazine (V) and 5, 8‐dibromopyrazino[2, 3‐d]pyridazine (Va). When V was treated with various benzyl mercaptans and alkoxides the corresponding disubstituted derivatives were obtained. Compound V when allowed to react with aromatic amines gave 5, 8‐bisamino‐pyrazino[2,3‐d]pyridazines, however, with aliphatic amines only mono substituted products were obtained substituted in the 8‐position. The reaction of pyrazine‐2, 3‐dinitrile with hydrazine gave 5, 8‐diaminopyrazino[2, 3‐d]pyridazine (X).
Oxazolo[3,2‐a]pyridinium salts
Authors: Bradsher C. K. , Zinn Mary F. 
Published: March 2009

AbstractThe first synthesis of the aromatic oxazolo[3,2‐a]pyridinium ring system has been accomplished by the cyclization of 1‐acetonyl‐ or 1‐phenacyl‐2‐pyridones. Through use of the analogous quinolones and 2‐(p‐bromophenacyl)‐1‐isoquinolone, benzologs of the new system have been prepared.