bluuebunny/crossref_metadata_2025 huggingface dataset:
Complete spectroscopic structural characterization of novobiocin, isonovobiocin, decarbamylnovobiocin, 2″‐(o‐Carbamyl)novobiocin, and novobiocin‐2″,3″‐carbonate
Authors: Crow Frank W. , Duholke Wayne K. , Hadden Chad E. , Smith Richard F. , Thamann Thomas J. , Kaluzny Brian D. , Hahn David A. , Mallory Christopher S. , Farley Kathleen A. , Martin Gary E.
Published: March 2009

The rigorous structural characterization of novobiocin, is reported using mass spectrometric, infrared and nmr spectroscopic analysis. Complete nmr assignments are reported. Previous reports in the literature had left some quaternary carbon resonances unassigned. Isonovobiocin and decarbamylnovobiocin, although known in the literature for a number of years, have never been completely characterized. Mass spectrometric fragmentation pathways and complete 1H and 13C nmr assignments are reported for these congeners for the first time. The mass spectral fragmentation pathway and nmr assignments are also reported for 2″‐(O‐carbamyl)novobiocin although the nmr assignments at lower field were reported previously. The structural characterization of novobiocin‐2″,3″‐carbonate observed in the Test Assay procedure used for Novobiocin is reported for the first time.
Synthesis and structure of novel 4‐arylhexahydro‐1H,3H‐pyrido[1,2‐c]pyrimidine derivatives
Authors: Herold Franciszek , Helbin Ewa , Król Marek , Wolska Irena , Kleps Jerzy
Published: March 2009

A series of new 4‐aryl‐hexahydro‐1H,3H‐pyrido[1,2‐c]pyrirnidine‐1,3‐dione derivatives4a‐kwere prepared by catalytic hydrogenation of 4‐aryl‐1H,2H‐pyrido[1,2‐c]pyrirnidine‐1,3‐diones3a‐k.The structures of compounds were determined by1H and13C nmr spectroscopy in solution. Steric hindrance caused twisting of the phenyl ring with respect to the pyridopyrimidine system, the effect was confirmed by X‐ray diffraction.
Cyclization of 2‐ and 3‐indolylthiobenzoic, phenylacetic and nicotinic acids and esters to novel indole‐containing tetracyclic ring systems
Authors: Hamel Pierre , Girard Mario , Tsou Nancy N.
Published: March 2009

A series of 2‐ and 3‐indolylthio benzoic, phenylacetic and nicotinic acids or esters were cyclized under dehydrative conditions affording several tetracyclic indole‐containing ketones, several of which constitute the first reported examples of novel ring systems, such as the [1]benzothiepino[2,3‐b] and [3,2‐b]indole and the pyrido[3′2′:5,6] and [3′4′:5,6]thiopyrano[2,3‐b] and [3,2‐b]indole as well as the [3′2′:5,6] and [3′4′:5,6][1,3]thiazino[3,2‐a]indole ring systems.
Synthesis of methyl 3‐amino‐4‐aryl(or methyl)sulfonyl‐2‐thiophenecarboxylates from 3‐alkoxy‐2‐aryl(or methyl)‐sulfonylacrylonitriles
Authors: Stephens Chad E. , Price Matthew B. , Sowell J. Walter
Published: March 2009

The synthesis of a series of methyl 3‐amino‐4‐aryl(or methyl)sulfonylthiophene‐2‐carboxylates by reaction of 3‐alkoxy‐2‐aryI(or methyl)sulfonylacrylonitriles with methyl thioglycolate in the presence of triethylamine is described. Hydrolysis/decarboxylation of the ester at the 2‐position and acylation of the resulting amine represents a convenient route to 4‐arylsulfonyl‐3‐carboxamidothiophenes. Attempted acylation of a title aminothiophene under standard conditions was unsuccessful.
A quantitative study of substituent effects on oxidative cyclization of some 2‐aryl‐substituted aldehyde thiosemicarbazones induced by ferric chloride and cupric perchlorate
Authors: Noto Renato , Meo Paolo Lo , Gruttadauria Michelangelo , Werber Giuseppe
Published: March 2009

As a development of our previous work, we performed a kinetic study of the oxidative cyclization reaction of some 2,4‐diaryl‐substituted aldehyde thiosemicarbazones 1a‐n induced by ferric chloride and by cupric perchlorate. The results of cyclization of 1a‐n were compared to those of the corresponding 2‐methyl derivatives. The kinetic data were analyzed by means of the Hammett's equation.
Acyliminium ion‐olefin cyclization leading to isoindolo[2,1‐a]quinoline derivatives
Authors: Pigeon Pascal , Othman Mohamed , Netchitaïlo Pierre , Decroix Bernard
Published: March 2009

Isoindolo[2,1‐a]quinolines 10, 11, 12 were synthesized from hydroxylactams 8 or 9 via an N‐acyliminium ion‐π‐olefin nucleophile cyclization reaction.
Polycyclic systems: Synthesis of isoindolo[2,1‐b]‐pyrrolo[1,2‐d][2,4]benzodiazocine and isoindolo‐[1,2‐d]pyrrolo[1,2‐a] [1,5]benzodiazocine
Authors: Othman Mohamed , Pigeon Pascal , Decroix Bernard
Published: March 2009

The synthesis of isoindolo[2,1‐b]pyrrolo[1,2‐d][2,4]benzodiazocine 7 and isoindolo[1,2‐d]pyrrolo[1,2‐a]‐[1,5]benzodiazocine 13 are described starting from 2‐(2‐methoxycarbonyl)benzylphthalimide 1a and ethyl α‐bromohomophthalate 9 respectively.
Studies on pyrazines. 35. An improved synthesis of bromopyrazines from hydroxypyrazines
Authors: Sato Nobuhiro , Narita Nobuhiko
Published: March 2009

The synthesis of bromopyrazines from hydroxypyrazines was successfully effected by the procedure via trimethylsilyloxypyrazines, the sequence of which proceeds under mild conditions and does not require the isolation of intermediate.
A convenient preparation of 1,3‐disubstituted dihydro‐2,4‐(1H,3H)pyrimidinediones
Authors: Deck L. M. , Papadopoulos E. P.
Published: March 2009

The ureas 3 which are obtained from 3‐(benzylamino)propanenitrile (1) and various isocyanates (2) cyclize readily upon heating in ethanol, in the presence of hydrochloric acid, to form 3‐substituted 1‐benzyldihydro‐2,4‐(1H,3H)pyrimidinediones (11) in good yield.
Syntheses, crystal structures, and metal ion complexation studies of novel diaza‐18‐crown‐6 ligands containing aromatic thiol‐derived side arms
Authors: Su Ning , Bradshaw Jerald S. , Xue Guoping , Dalley N. Kent , Zhang Xian X. , Savage Paul B. , Krakowiak Krzysztof E. , Izatt Reed M.
Published: March 2009

The Mannich aminomethylation reaction of aromatic thiols has been used to produce diaza‐18‐crown‐6 ligands containing thiol‐derived side arms. Thiophenols were attached to the azacrown through N‐CH2‐S linkages even in the presence of hydroxy or acetamido groups. Heteroaromatic thiols containing N=C‐SH (or NH‐C=S) structural fragments were attached to diaza‐18‐crown‐6 by N‐CH2‐N linkages with the thiol becoming a thione function. X‐ray crystal structural analyses show the N‐CH2‐S and N‐CH2‐N linkages for some of the new macrocyclic compounds. Interactions of four of the new diaza‐18‐crown‐6 ligands with Na+, K+, Ba2+, Ag+, Zn2+, Cd2+, Ni2+, and Cu2+ were evaluated by calorimetric titration at 25° in methanol. The results show that these ligands form stable complexes with many of the metal ions studied.
Synthesis and transformations of stereoisomeric ethyl 2‐isothiocyanato‐1‐cyclopentanecarboxylatesm
Authors: Palkó Márta , Fülöp Ferenc , Evanics Ferenc , Bernáth Gábor
Published: March 2009

Ethyl vis‐ and trans‐2‐isothiocyanato‐1‐cyclopentanecarboxylates 2 and 7 were prepared by the reaction of the corresponding alicyclic ethyl 2‐amino‐1‐carboxylates and thiophosgene. The cis‐isothiocyanato compound 2 underwent ring closure with amines in one or two steps, resulting in 3‐substituted‐cis‐2‐thioxocyclopenta[d]pyrimidin‐4‐ones 3a‐g. The trans isomer 7 failed to cyclize, but gave carboxamide 8a,b or thiourea ester derivatives 9a,b.
New lipophilic crown ethers with intraannular carboxylic acid groups: Synthesis and alkali metal cation extraction
Authors: Bratton Larry D. , Huh Hwang , Bartsch Richard A.
Published: March 2009

A six‐step synthetic route to four lipophilic crown ethers with intraannular carboxylic acid groups and ring sizes of 15‐crown‐4, 18‐crown‐5, 21‐crown‐6 and 24‐crown‐7 is described. Eight new polyether compounds that bear inward‐facing bromo and formate ester substituents are prepared as synthetic intermediates. Selectivities and efficiencies of the four new lipophilic crown ether carboxylic acids in competitive alkali metal cation extraction from aqueous solutions into chloroform are evaluated.
New isomeric N‐substituted hydrazones of 2‐, 3‐ and 4‐pyridinecarboxaldehydes and methyl‐3‐pyridylketone
Authors: Wyrzykiewicz Elzbieta , Blaszczyk Alfred
Published: March 2009

Twelve compounds unknown in the literature N‐(E)‐2‐stilbenyloxymethylenecarbonyl substituted hydrazones of 2‐, 3‐ and 4‐pyridinecarboxaldehydes, as well as methyl‐3‐pyridylketone have been prepared. The stereochemical behavior of these compounds in dimethyl‐d6 sulfoxide solution has been studied by 1H NMR technique. The E geometrical isomers and cis/trans amide conformers have been found for N‐substituted hydrazones 1–12. EI induced mass spectral fragmentation of these compounds were also investigated. The data obtained create the basis for distinguishing isomers.
Synthesis of lariat ether carboxylic acids based on dibenzo‐16‐crown‐5
Authors: Bartsch Richard A. , Cowey Charles L. , Elshani Sadik , Goo Mi‐Ja , Huber Vincent J. , Ivy Sheryl N. , Johnson Russell J. , Kim Jong Seung , Luboch Elzbieta , Mcdonough Joseph A. , Pugia Michael J. , Son Byungki , Zhao Qiang
Published: March 2009

Synthetic routes to forty‐seven dibenzo‐16‐crown‐5 compounds with pendant carboxylic acid groups are reported. When taken together with previously described lariat ether carboxylic acids, these new compounds provide several series with systematic structural variations including changes in the identity and attachment site(s) of one or more lipophilic groups and the length of the spacer that connects the carboxylic acid group to the polyether framework.
Synthesis of 4‐(7‐diethylaminocoumarin‐3‐yl)benzeneisocyanate (DACB‐NCO): A highly sensitive fluorescent derivatization reagent for alcohols in high‐performance liquid chromatography
Authors: Takechi Haruko , Goto Yasuo , Takahashi Hajime , Machida Minoru
Published: March 2009

4‐(7‐Diethylaminocoumarin‐3‐yl)benzeneisocyanate (DACB‐NCO) was synthesized as a new fluorescent derivatization reagent for alcohols for use in high‐performance liquid chromatography (hplc). Saturated alcohols (C6‐C22) were derivatized in good yields into the corresponding fluorescent DACB‐carbamic esters by treating with DACB‐NCO. The DACB‐carbamic esters of these alcohols were clearly separated on a reversed‐phase hplc column (Inertsil ODS‐2, mobile phase: methanol‐water, excitation wavelength 402 nm; emission wavelength 488 nm). The detection limit (S/N = 3) of cetyl alcohol, as a test compound, was 5 fmol/10 μl.
The chemistry of the highly reactive 2,6‐bis(bromomethyl)‐4‐pyrone
Authors: Löwe Werner , Brätter Stefanie A. , Weber Manuela , Luger Peter , Buddrus Joachim
Published: March 2009

Under basic conditions 2,6‐bis(bromomethyl)‐4‐pyrone 8 reacts with tetraethylene glycol to yield the unexpected macrocycle 9, which is related to the antibiotic Kjellmanianone 10. We propose that this ring transformation proceeds via the cyclopropyl intermediate d (Scheme 2), which undergoes a ring opening reaction comparable to the Favorskii rearrangement. Also, 8 reacts with methanol/sodium methoxide to yield the 3(2H)‐furanone derivative 11, the formation of which is suggested to proceed via the intermediate k with a carbenium‐oxonium‐ion subunit (Scheme 3). The structure of the 3(2H)‐furanone derivative was confirmed by X‐ray analysis.
A new dimerization reaction producing 2‐amino‐9‐oxopyrrolo‐[2,1‐b]quinazoline‐1‐carbonitriles and analogous pyrrolo‐[1,2‐a]thieno[3,2‐d] pyrimidinecar bonitriles
Authors: Gütschow Michael , Powers James C.
Published: March 2009

A series of 2‐alkylthio‐4‐oxo‐3‐quinazolineacetonitriles 4 and 2‐alkylthio‐4‐oxothieno[3,2‐d]pyrimidine‐3‐acetonitriles 8 was prepared. Upon treatment with sodium hydride, compounds 4 and 8 react to give 2‐amino‐4,9‐dihydro‐9‐oxopyrrolo[2,1‐b]quinazoline‐1‐carbonitriles 9 and 6‐amino‐4,9‐dihydro‐9‐oxopyrrolo[1,2‐a]thieno[3,2‐d]pyrimidine‐7‐carbonitriles 10, respectively. The transformation of compounds 4 and 8 to the tricyclic aminonitriles 9 and 10 involves a dimerization step followed by a pyrrole cyclization. The tert‐butyl ester derivatives 4d and 8d upon treatment with sodium hydride underwent a Thorpe‐Ziegler cyclization to provide enaminoesters of fused 1,3‐thiazines (16 and 17, respectively) as major products.
A facile synthesis of some thieno/furo‐[2,3‐d]pyrimidine‐2‐yl‐thioacetic acid derivatives
Authors: Demirayak S̨Eref , Mohsen Usama Abu
Published: March 2009

The reaction of 2‐(α‐chloroacetamido)‐3‐cyano‐4,5‐disubstituted thiophenes/furanes with ammonium thiocyanate in methanol or ethanol afforded methyl or ethyl (4‐amino‐5,6‐disubstituted thieno/furo[2,3‐d]‐pyrimidine‐2‐yl)thioacetates in good yields.
Preparation of novel 2‐(benzo[b]furan‐2‐yl)‐1H‐imidazolines for photoaffinity labelling and affinity isolation of imidazoline binding
Authors: Clews Proteins J. , Ramsden Christopher A. , Morgan Noel G.
Published: March 2009

The preparations of 5‐aminoefaroxan 8 and 5‐azidoefaroxan 9, which retain the capacity to stimulate insulin secretion via the putative I3 imidazoline receptor and are useful biological tools for affinity chromatography studies and photoaffinity labelling studies of imidazoline binding proteins, are described
Structure elucidation, conformational analysis and thermal effects on membrane bilayers of an antimicrobial myricetin ether derivative
Authors: Demetzos C. , Angelopoulou D. , Kolocouris A. , Daliani I. , Mavromoustakos T.
Published: March 2009

The membrane perturbing 3,7,4′,5′‐tetramethyl ether of myricetin 1 was isolated from Cistus monspelien‐sis L. Its structure was elucidated and its conformational properties were explored using a combination of 2D NMR spectroscopy and computational chemistry. The obtained results showed that compound 1 adopts four enantiomeric pairs of low energy conformers characterized: (a) by an aromatic ring B twisted through rotation about C2‐C1′ bond from the rigid isoflavone ring; (b) a 4′‐O‐CH3 bond oriented out of the plane with equal probability upwards or downwards the phenyl ring B, while all the other O‐CH3 bonds are oriented in the plane of the aryl ring. Two of these enantiomeric pairs are lowest in energy. These possible bioactive con‐formers are possibly stabilized by van Der Waals interactions. The 3′,5‐diacetyl derivative 2 of compound 1 was synthesized and its structure elucidation was achieved based on the chemical shift assignment of the parent compound 1. The Differential Scanning Calorimetry (DSC) results revealed that the degree of the thermal effects exerted by the flavonoids at dipalmitoylphosphatidyl choline (DPPC) bilayers followed the order 1 > 2 > myricetin. Their antimicrobial activity against Gram positive bacteria followed the same order.
2‐Arylethenyl‐2′‐arylethynyl sulfones: A potential source for some spiroheterocycles
Authors: Reddy Dandu Bhaskar , Babu Nalla Reddy Chandrasekhar , Padmavathi Venkatapuram
Published: March 2009

The double Michael addition of dimethyl malonate to 2‐arylethenyl‐2′‐arylethynyl sulfones (3) resulted in 3,5‐diaryl‐5,6‐dihydro‐4,4‐dimethoxycarbonyl‐1‐thiin‐1,1‐dioxides (4). The latter on cyclocondensation with urea / thiourea / hydrazine hydrate / hydroxylamine hydrochloride gave spiroheterocycles.
Bicyclic [b]‐heteroannulated pyridazine derivatives. 9. cyclization reactions of 4,4‐dimethyl‐ and 4‐phenyltetrahydropyridazine‐3,6‐dione 3‐hydrazones with esters of keto dicarboxylic acids
Authors: Wejroch Krystyna , Lange Jerzy , Kielak Anna , Karolak‐Wojciechowska Janina , Sośnicki Jacek , Jagodziński Tadeusz
Published: March 2009

Bis(ethoxycarbonyl)alkylidene derivatives 4 and 5 of the respective title hydrazones were obtained in the reactions with diethyl oxomalonate, diethyl oxosuccinate, diethyl 2‐oxoglutarate, and diethyl oxalo‐propionate as mixtures of geometric isomers with high predominance of one of them. On heating at 160‐200° without any solvent or on refluxing in ethanol 4 cyclized to yield the corresponding pyri‐dazino[6, 1‐c]triazines 6, whereas heating of 5 gave, depending on the chain length, the corresponding pyra‐zolylpyridazines 8b and 8d or the pyridazinylpyridazine 8c. X‐ray analysis was used to determine the structures of 6 and 8; the unit cell of 6c was found to accommodate 16 molecules representing four conforma‐tional varieties. The different behavior of 4 and 5 in the cyclization reactions was interpreted in terms of the tautomeric equilibrium which was shifted towards the enamine form in 4, and towards the imine form, in 5. Transmission of a long‐range chirality effect in 4d and 5a‐d manifested itself in the 1H nmr spectra as the magnetic non‐equivalence of the CH2 protons in one or both ester ethyl groups.
Synthetic approaches to 4,8‐dimethyl‐5′‐(N‐pyridiniummethyl)‐ 4′,5′‐dihydropsoralens and 4,8‐dimethyl‐5′‐ (N‐aminomethyl)‐ 4′,5′‐dihydropsoralens
Authors: Whittemore Marilyn S. , Heindel Ned D. , Jabin Ivan , Guillon Christophe , Mcneel Thomas E. , Rapp Robert D. , Heck Diane E. , Laskin Jeffrey D.
Published: March 2009

New synthetic approaches to 4,8‐dimethyl‐5′‐(N‐pyridiniummethyl)‐4′,5′‐dihydropsoralens and 4,8‐dimemyl‐5′‐(N‐aminomethyl)‐4′,5′‐dihydropsoralens are described. The 5′‐halomethyl‐4′,5′‐dihydro‐psoralen precursors are formed by electrophilic ring closures of 4,8‐dimethyl‐6‐allyl‐7‐hydroxycoumarin. The ring‐closure reactions may also be applied to the synthesis of 5′‐halomethyl‐4‐methyl‐4′,5′‐dihydroangelicins. The compounds are potential therapeutic agents for improved psoralen ultraviolet A radiation treatment.
Synthesis and characterization of 7, 16‐bis(phenylazo)tetraaza[14]annulenes
Authors: Sakata Kazunori , Yamashita Junichi , Hashimoto Mamoru , Tsuge Akihiko , Tanoue Yasuhiro
Published: March 2009

The diazo coupling reaction between a tetraaza[14]annulene (1) and a series of 4‐substituted phenyl‐diazonium tetrafluoroborates yielded the corresponding 7, 16‐disubstituted products. Mass spectra indicate the presence of molecular ion peaks that substantiate the 7,16‐disubstituted products (4); the lack of olefinic proton signals corresponding to the 7,16‐ position in the 1H nmr spectra of 4 also show that diazo coupling has taken place. Analysis of signals corresponding to the methyl groups of 4 in their 1H and 13C nmr spectra indicate that the imine‐bis‐hydrazone form is present for compounds that do not contain p‐methoxyphenyl groups. However, analysis of methyl signals in the nmr specta of compounds 4 containing p‐methoxyphenyl groups show that the bis‐azo form and the imine‐bis‐hydrazone form are present through tautomerism. Complexation with nickel(II) ion induces the formation of the bis‐ azo structure.
A new synthesis of 4‐cyano‐1,3‐dihydro‐2‐oxo‐2H‐imidazole‐5‐(N1‐tosy1)carboxamide : reactive precursor for thiopurine analogues
Authors: Hamad Abdel‐Sattar S. , Derbala Hamed D. A. Y.
Published: March 2009

N‐[(5‐Cyano‐2‐oxoimidazolidin‐4‐yl)‐iminomethyl]‐p‐toluensulfonamide 3 was prepared in fairly good yield by the base catalyzed cyclisation of N‐[(Z)‐2‐amino‐1,2‐dicycanovinylcarbamoyl]‐p‐toluenesulfon‐amide 2. The N‐[(Z)‐2‐amino‐1,2‐dicycanovinyl carbamoyl]‐p‐toluenesulfonamide 2 was reacted readily with two molar amount of p‐nitrobenzaldehyde at room temperature in the presence of base to give 7,8‐dihy‐dro‐2‐(4‐nitrophenyl)‐8‐oxo‐9‐tosylpurine‐6‐carboxamide 8. Thiation of compounds 3 and 8 using Lawesson's reagent in tetrahydrofuran gave novel thioimidazoles 4, 5, and 6 and thiopurines 9, 10, and 11, which have been characterized spectroscopically.
A kinetic study of the high temperature rearrangement of 4‐ethyl‐3,5‐diphenyl‐4H‐1,2,4‐triazole
Authors: Gautun Odd R. , Carlsen Per H. J.
Published: March 2009

The kinetics of the thermal rearrangement 4‐ethyl‐3,5‐diphenyl‐4H‐1,2,4‐triazoles, 1, to the corresponding 1‐ethyl‐3,5‐diphenyl‐1‐alkyl‐1H‐1,2,4‐triazoles, 2, was studied in 15‐Crown‐5 and octadecane at 330 °C. The reaction was very slow in octadecane but proceed well in 15‐Crown‐5. The reaction order for the reaction was not constant but changed from an initial second order rate law towards a first order rate law as the reaction progressed. This was confirmed by the concentration dependent reaction order, nc, which was larger than the time dependent rate law, nt. The rationale for the observation was, that at high substrate concentrations the reaction order was second order while at lower concentrations a competing solvent assisted reaction plays an increasing important role. The data were in agreement with a mechanism in which the neutral 4‐alkyl‐triazoles in an intermolecular nucleophilic displacement reaction form a triazolium triazolate, which in a subsequent nucleophilic reaction gives the observed product.
Synthesis of 3,4‐dihydro‐1(2H)‐isoquinolinonesxs
Authors: Showalter H. D. Hollis , Sercel Anthony D. , Stier Michael A. , Turner William R.
Published: March 2009

Approaches toward the preparative‐scale synthesis of target 3,4‐dihydro‐1(2H)‐isoquinolinones 1–3 are presented. Compounds 1 and 2 were prepared via a Schmidt rearrangement on easily obtained indanone precursors, but in low overall yield. A better method to make this class of compounds is exemplified by the large‐scale synthesis of 2 via a Curtius rearrangement sequence. Thus, high‐temperature thermal cyclization of an in situ formed styryl isocyanate from precursor 8 in the presence of tributylamine gave the corresponding 1(2H)‐isoquinolinone (9). Catalytic hydrogenation of 9 provided the desired 3,4‐dihydro‐5‐methyl‐1(2H)‐isoquinolinone (2) in 65 % overall yield. Similar reduction of a commercially available 5‐hydroxy‐1(2H)‐isoquinolinone precursor 10 followed by an O‐alkylation/amination sequence gave target 3 in good overall yield. The route proceeding via the Curtius rearrangement is recommended for large scale synthesis of other 3,4‐dihydro‐1(2H)‐isoquinolinones. Only when deactivating substituents or sensitive functionality within the benzenoid ring render the high temperature ring closure of the intermediate isocyanate inefficient might a Schmidt rearrangement protocol be the method of choice.
Synthesis of new thienotriazolopyrimidine and thienopyrimidotetrazine derivatives from bifunctional intermediates
Authors: Modica Maria , Santagati Maria , Santagati Andrea
Published: March 2009

New compounds containing the thienotriazolopyrimidine and thienopyrimidotetrazine skeleton are prepared from the bifunctional intermediates 2,3‐diamino‐5,6‐dimethylthieno[2,3‐d]pyrimidin‐4(3H)‐one derivatives 13–17. The 2,3‐dihydro‐3‐substituted‐5,6‐dimethylthieno[2,3‐d]pyrimidin‐4(1H)‐one derivatives 8–12 are also prepared.
Synthesis of new pyrazolo[1,5‐a]pyrimidines and pyrazolo[3,4‐b]pyridines
Authors: Al‐Mousawi Saleh M. , Mohammad Mohammad A. , Elnagdi Mohamad H.
Published: March 2009

While 3(5)‐aminopyrazole reacts with enaminonitrile to yield pyrazolo[1,5‐a]pyrimidines, 3‐amino‐5‐pyrazolone reacts with the same reagents to yields pyrazolo[3,4‐b]pyridines.
A facile synthesis of biogenetic precursor, puerarone, isolated from Pueraria sp
Authors: Khan Riaz A. , Kapil Randhir S.
Published: March 2009

Puerarone was synthesized using chalcone oxidation with thallium (III) trinitrate and chromenation of the resulting isoflavone using 3‐hydroxyisovaleraldehyde dimethylacetal. The key demethylation step was achieved with boron tribromide.
Synthesis of novel pyrazolopyrrolopyrazines, potential analogs of sildenafil
Authors: Kopp Marina , Lancelot Jean‐Charles , Dallemagne Patrick , Rault Sylvain
Published: March 2009

Synthesis of novel pyrazolopyrrolopyrazines is herein described with the aim to reach new specific PDE‐5 inhibitors of potential clinical interest in male erectile dysfunction.
Efficient one pot preparation of variously substituted thieno [2,3‐b] thiophene
Authors: Cornel Alain , Kirsch Gilbert
Published: March 2009

An efficient one pot access to variously substituted thieno[2,3‐b]thiophene is described. The title compounds were obtained from 1,3‐dicarbonyl or equivalent compounds, carbon disulfide and halomethyl derivatives in good to high yields and fully characterized.
A revision of the alcoholysis and alkanethiolysis of 3‐amino‐6‐chloropyridazine
Authors: Maes Bert U. W. , Lemière Guy L. F. , Dommisse Roger , Haemers Achiel
Published: March 2009

The synthesis of 3‐amino‐6‐alkoxy‐ and 3‐amino‐6‐alkylthiopyridazines via nucleophilic aromatic substitution on 3‐amino‐6‐chloropyridazine is described. In contrast to literature reports, no pressure tube is required to perform these reactions.
Synthesis of methyl‐2,4‐bis(cyclohexane)dispiro‐1,2,3,4,4a,5,6,7‐octahydro‐(lH,3H)quinazoline‐8‐carbodithioate derived from cyclohexanone in one step
Authors: Contreras Ricardo R. , Fontal Bernardo , Reyes Marisela , Suárez Trino , Bellandi Fernándo , Bahsas All
Published: March 2009

The new compound Methyl‐2,4‐bis(cyclohexane)dispiro‐1,2,3,4,4a,5,6,7‐octahydro‐(1H,3H)‐quinazo‐line‐8‐carbodithioate has been synthesized from cyclohexanone and carbon disulfide. It has been characterized by uv‐visible, FTTR, mass spectra and a complete structure proposed based on 1H and 13C NMR spectroscopy.
New compounds in ring‐opening reaction of 5‐substituted epoxyisoindolines
Authors: Mance Ana Dunja , Borovička Branko , Jakopčić KreŠImir , Pavlović Gordana , Leban Ivan
Published: March 2009

Methoxy or nitro group present in the furan ring of tertiary alkenylfurfurylamine changes the expected results of both, the intramolecular [4+2]cycloaddition and the acid catalyzed ring‐opening reaction of the derived oxatricycloadduct. With a 5‐methoxy group, in addition to the expected 5‐methoxyisoindoline 3, the corresponding hydroxy derivative 5 was obtained. On the other hand a 5‐nitro group changes the outcome of the reaction even more profoundly. Instead of the expected 5‐nitroisoindoline 12, 5‐nitro‐substituted epoxy‐isoindoline 6 submitted to ring‐opening reaction with the mixture of hydrobromic and acetic acid, yielded the mixture of bromo‐substituted epoxy compounds 7,8, 9 and/or bromo‐substituted isoindolines 10 and 11.
On triazoles XLIV [1]. synthesis of new ring systems containing imidazo[2′,1′:3,4] [1,2,4] triazolo [1,5‐a]pyrimidine and imidazo[1′,2′:2,3][1,2,4]triazolo[1,5‐a]pyrimidine skeleton
Authors: Berecz Gábor , Reiter József , Argay Gyula , Kálmán Alajos
Published: March 2009

Dedicated to Dr. János Császár on the occasion of his 70th birthday

Ring transformation of 2‐cyanoimido‐3‐methyl‐1,3‐oxazolidine (10) yielded 5‐amino‐3‐[N‐(2‐hydrox‐yethyl)‐N‐methyl]amino‐1H‐1,2,4‐triazole (6) that was ring closed with different β‐keto esters to 2‐[N‐(2‐hydroxyethyl)‐N‐methyl]amino‐1,2,4‐triazolo[1,5‐a]pyrimidinones (4). Cyclisation of derivatives 4 led to imidazo[2′,1′:3,4][1,2,4]triazolo[1,5‐a]pyrimidines (2) and imidazo[1′,2′:2,3][1,2,4]triazolo[1,5‐a]pyrim‐idines (3) representing 10 novel ring systems. Besides spectroscopical evidence of structure of derivatives 2 and 3 X‐ray diffraction analysis of derivative 2b was also performed.
On triazoles XLV [1]. synthesis of 5,7‐diamino‐1,2,4‐triazolo[1,5‐a] [1,3,5]triazines
Authors: Berecz Gábor , Pongó László , Kövesdi István , Reiter József
Published: March 2009

Dedicated to Professor András Messmer on the occasion of his 80th birthday

The reaction of differently substituted 5‐amino‐1,2,4‐triazoles (5) with isothiourea derivatives (3) to yield isomeric 5,7‐diamino‐1,2,4‐triazolo[1,5‐a][1,3,5]triazines (6 and 7), previously described as not proceeding in melt, was performed in different solvents as well as in the melt at 150‐160°. It was proved that the above reaction had rather general validity. The structure of isomers 6 and 7 were proved spectroscopically. The structure of 6/5 (Q = ethylamino) was corroborated with single crystal X‐ray diffraction determination, as well.
Diarylthiopyrimidines and pyridines: Synthesis and biological activity
Authors: Delia Thomas J. , Kanaar John B. , Knefelkamp Elizabeth
Published: March 2009

Prior work with diarylethers of pyrimidine, pyridine, and benzene showed encouraging antitumor results. As an extension of that work the synthesis of diarylthio derivatives of pyrimidine and pyridine has been accomplished. The synthetic scheme employed the nucleophilic displacement of chlorines from trichloropyrimidine, 1, dichloropyrimidines 4 and 6, and 2,6‐dichloropyridine 8 using the anion of thiophe‐nols 2. Antitumor evaluation by the National Cancer Institute showed no useful activity.
Unexpected ring closure reaction of α,β‐unsaturated ketones with aminoguanidine. entry into 1,3,5‐trisubstituted pyrazoles
Authors: Světlík Jan , Šallai Ladislav
Published: March 2009

Cyclizations of α,β‐unsaturated ketones with aminoguanidine under neutral conditions were examined. In contrast to literature reports of 1,2,4‐triazines as reaction products, formation of 5‐aryl‐4,5‐dihy‐dro‐3‐methyl‐1H‐pyrazole‐1‐carboximidamides and carboxamides was observed. An explanation based on the Hard‐Soft Acid‐Base principle is presented and the probable causes of divergent reaction pathways are discussed.
Synthesis and spectral properties of 7‐chloro‐5‐[(o‐ and p‐R1)phenyl]‐1‐R2‐3H‐[1,4]benzodiazepin‐2‐ones
Authors: Cortés Eduardo Cortés , Martínez Isidro Ebromares , Mellado Olivia García
Published: March 2009

A series of twelve new 7‐chloro‐5‐[(o‐ and p‐R1)phenyl]‐1‐R2‐3H‐[1,4] benzo‐diazepin‐2‐ones, which have possible pharmacological properties were synthesized. The synthesis of all the final compounds was carried out by four steps. The structure of all final products was corroborated by ir, 1H nmr, 13C nmr and ms, and have been obtained in 35‐94% yield.
Synthesis of tetronic acid derivatives from novel active esters of α‐hydroxyacids
Authors: Mitsos Christos , Zografos Alexandras , Igglessi‐Markopoulou Olga
Published: March 2009

Active esters, produced by condensation of O‐acetyl protected α‐hydroxyacids with N‐hydroxysuccin‐imide, react with anions of active methylene compounds to afford β,β‐tricarbonyl derivatives which upon deprotection undergo cyclization to 3‐alkoxycarbonyl and 3‐acyl tetronic acids. Incorporation of (S)‐2‐ace‐toxyphenylacetic acid in this reaction sequence enables the synthesis of optically active 5‐phenyltetronic acid derivatives.
Determination of aromaticity indices of thiophene and furan by nuclear magnetic resonance spectroscopic analysis of their phenyl esters
Authors: Lee Chang Kiu , Yu Ji Sook , Lee Hye‐Jin
Published: March 2009

A series of m‐ and p‐substituted phenyl benzoates, 2‐thienoates, and 2‐furoates were prepared and their 1H and 13C nmr spectroscopic characteristics were examined. In general, good correlations were observed between the chemical shift values of protons and carbons of the acyl aromatic rings and the Hammett σ. Plots of the chemical shift values of the carbonyl carbons of the benzoates against those of the 2‐thienoates and 2‐furoates gave an excellent correlation and the values of the slopes are 0.85 and 0.75, respectively, in dimethyl sulfoxide‐d6 and 0.90 and 0.78, respectively, in chloroform‐d. The values could be considered as a set of aromaticity indices.
Synthesis of 2‐(1‐methyl‐1,2,5,6‐tetrahydropyridin‐3‐yl)benzimidazoles
Authors: Jung Myung Hee , Park Jung Mee , Lee Ihl‐Young Choi , Ahn Mija
Published: March 2009

A useful approach for the synthesis of pharmacologically active tetrahydropyridinylbenzimidazoles is described. 2‐Pyridin‐3‐ylbenzimidazoles 3a‐d have been synthesized by condensation of 3‐pyridinecarbox‐aldehyde 1 with substituted 1,2‐phenylenediamines 2a‐d following oxidative cyclization with iodobenzene diacetate. Methylation of 3a‐d with iodomethane and potassium hydroxide, subsequent formation of methylpyridinium salts 4a‐d and 7a‐d and reduction thereafter afforded tetrahydropyridinylbenzimidazoles 5a‐d and 8a‐d.
The synthesis of 4‐amino‐3‐(2‐pyridyl)pyrazolo[5,1‐c][1,2,4]triazine and some of its derivatives
Authors: Cankař Petr , Slouka Jan
Published: March 2009

A mixture of both geometrical isomers of hydrazones 3a‐3e was obtained by the coupling reactions of pyrazole‐3‐diazonium salts 2a‐2d and benzenediazonium chloride 2e with 2‐pyridylacetonitrile 1. Hydrazones 3a‐3d were cyclized to the corresponding 4‐amino‐3‐(2‐pyridyl)pyrazolo[5,1‐c][1,2,4]triazines 4a‐4d.
Synthesis and properties of bowl‐shaped homotriazacalix[3 and 6] arenes and the acyclic analogues
Authors: Ito Kazuaki , Sato Tomokazu , Ohba Yoshihiro
Published: March 2009

Bowl‐shaped chiral homotriazacalixarenes were prepared by the cyclization reactions of chiral triamines with three equimolar amounts of bis(chloromethyl) phenols or bis(chloromethyl) phenol‐formaldehyde dimers in moderate yields. The corresponding acyclic phenol‐formaldehyde oligomers were also synthesized. The structural analysis of the macrocycles by nmr and circular dichroism spectra imply the existence of chiral transmission from the point chirality of the cysteine bridge to the cyclophane moiety. Their cyclic and acyclic compounds have a π‐base cavity large enough to include the ammonium ion.
N‐phenyl‐substituted pyrrolidines, piperidines and azabicyclics by a tandem reduction‐double reductive amination reaction
Authors: Bunce Richard A. , Herron Derrick M. , Lewis Jason R. , Kotturi Sharadsrikar V.
Published: March 2009

N‐Phenyl‐substituted pyrrolidines and piperidines have been synthesized by catalytic reduction of nitrobenzene in the presence of 4‐ and 5‐oxoaldehydes, respectively. The process involves reduction of the aromatic nitro group to give the N‐phenylhydroxylamine or aniline followed by reductive amination with the two carbonyl functional groups. Monocyclic systems are generally formed in high yield and are easily purified. The method has also been extended to the synthesis of fused N‐phenylazabicyclics from 2‐(3‐oxo‐propyl)cycloalkanones. A high degree of diastereoselectivity for the trans‐fused product is observed in substrates having an ester group α to the cycloalkanone carbonyl. Bicyclic precursors lacking this ester group give mixtures of cis and trans products. Finally, contrary to previous reports, we have demonstrated that aniline can be substituted for nitrobenzene in these reactions.
Solid‐phase synthesis of a novel series of 2,3,4,5‐tetrahydro‐1,4‐benzodiazepin‐2,5‐dione libraries
Authors: Migihashi Chiaki , Sato Fuminori
Published: March 2009

An efficient solid‐phase synthetic method for 2,3,4,5‐Tetrahydro‐1,4‐benzodiazepin‐2,5‐diones, having amine derivatives on the benzene ring, was developed. This method has been successfully applied to the synthesis of several spatially separated drug‐like and information‐rich small‐molecule libraries composed of 400 compounds using ACT‐496 automatic synthesizer and the IRORI radio frequency‐encoded split‐mix synthesis technology.
Synthesis of some novel annelated 1,2,3‐selena/thiadiazoles and 2h‐diazaphospholes
Authors: Padmavathi Venkatapuram , Reddy Dandu Bhaskar , Reddy Tippireddy Venkat Ramana , Reddy Kamireddy Audisesha
Published: March 2009

A number of annelated heterocyclic indene derivatives having 1,2,3‐selena/thiadiazole and 2H‐1,2,3‐diazaphosphole rings have been synthesized by exploiting the α‐ketomethylene functionality in some novel 1‐methyl‐piperidin‐4‐ones and 1‐oxo‐tetrahydrothiopyran‐4‐ones and were characterized by their physical and spectral data.
N‐Azolylmethyl ketones as building blocks in heterocyclic synthesis: Synthesis of new polyfunctionally substituted azolylarylazophenols, azolylpyridones and azolylthiophenes
Authors: Al‐Saleh Balkis , El‐Apasery Morsy Ahmed , Abdelkhalik Mervat Mohammed , Elnagdi Mohammed Hilmy
Published: March 2009

The title compounds 1a‐b and 2 reacted with 2‐arylhydrazonopropanals 3a‐c to yield polyfunctionally substituted azolylarylazophenols 5 and 8. The reaction of 1b and 2 with phenylisothiocyanate in the presence of α‐haloketones afforded the azolylthiophenes 12a,b and 13a,b. The reaction of 20 with α‐haloketone afforded 5‐benzotriazol‐1‐yl‐6‐methyl‐2‐(2‐oxopropylsulfanyl)nicotinonitrile 21 that was utilized as building blocks for the synthesis of condensed pyridines. Compound 21 was condensed with dimethylformamide dimethylacetal to yield thieno[2,3‐b]pyridin‐3‐yl‐N, N‐dimethylformamidine derivative 22. This was further cyclized with sodium hydride to 1H‐fhieno[2,3‐b; 4,5‐b']dipyridin‐4‐one derivative 23.
Synthesis of 1‐azabicyclic systems by double cyclization
Authors: Oka Mitsuru , Baba Kunihisa , Hamajima Hitoshi , Unno Ryoichi , Matsumoto Yukiharu , Nakamura Kensuke , Dong Lulu
Published: March 2009

5‐Cyano‐1‐azabicyclo[3.3.0]octane (1) was prepared in one step from 1,7‐dichloro‐4‐heptanone (4) under mild conditions. The application of this method for the preparation of 5‐cyano‐4,6‐dimethyl‐1‐azabicy‐clo[3.3.0]octane (11) gave two diastereomers in equilibrium. The NMR measurements of 11 and its reduced compound 15 showed that the major isomer is the cis‐exo form, and the minor isomer is the trans form. Molecular orbital calculations indicated that the cis‐exo form is more stable than the trans form, in agreement with the experimental results. Furthermore, 6‐cyano‐1‐azabicyclo[4.3.0]nonane (17) and 1‐azabicy‐clo[4.4.0]decane (19), both including a six‐membered ring, were prepared from appropriate haloketones by using this double cyclization method.
Azinoiminophosphorane mediated 4H,8H‐1,2,4‐triazolo[1,5‐C]‐[1,3]oxazepin‐4‐ones and 5,6‐dihydro‐7H, 12H‐naphtho[2,1‐f]‐[1,2,4]triazolo[1,5‐c][1,3]oxazepin‐7‐ones synthesis
Authors: Kim Kyoung Tae , Lee Chang Hoon , Lee Kee‐Jung
Published: March 2009

The aza‐Wittig reactions of benzaldehyde‐, acetophenone‐ and benzophenone 1‐[(triphenylphosphor‐anylidene)amino]ethylidenehydrazones (1) with 2,3‐furandiones 6 provide a new route to 4H,8H‐1,2,4‐triazolo[1,5‐c][1,3]oxazepin‐4‐ones 14 or 5,6‐dihydro‐7H,12H‐naphtho[2,1‐f|[1,2,4]triazolo[1,5‐c]‐[1,3]oxazepin‐7‐ones 17 via the thermal reaction of the expected azinoimine vinylogous lactones.
New reactions of carbon suboxide with alkynes
Authors: Casu Laura , Bonsignore Leonardo , Cottiglia Filippo , Loy Giuseppe , Maccioni Elias
Published: March 2009

Synthesis of 3,4,7,8‐tetraalkyl‐2‐oxa‐bicyclo[4.2.0]octa‐1(6),3,7‐trien‐5‐ones(4a‐d),4,5,7,8‐tetraalkyl‐2‐oxa‐bicyclo[4.2.0]octa‐1(6),4,7‐trien‐3‐ones (6a‐d) and 3,4,7,8‐tetraalkyl‐2H,5H‐cyclobuta[b]pyrano‐[2,3‐d]pyran‐2,5‐diones (7a‐d) from the reaction of alkynes (la‐d) with carbon suboxide (2) in various molar ratios is described.
Synthesis and biological evaluation of structural variants of carbazoquinocin C
Authors: Aygün Alparslan , Pindur Ulf
Published: March 2009

Some new structural variants of the alkaloid carbazoquinocin C were synthesized in a few steps with good to excellent yields. The key step comprises a cyclisation reaction of appropriate 2‐vinylindoles with oxalyl chloride. The carbazole‐3,4‐quinones are able to trap oxygen‐centred radicals. In some biological/biochemical assays some of these compounds exhibit extraordinary results including inhibition of cyclooxygenase‐1 and 5‐lipoxygenase in the μM‐range. Moreover some of the carbazoquinocin C‐variants inhibit significant oxidative damage of cellular DNA in nM‐range.
Preparation of 5,5′‐pyrilidene and 5,5′‐quinolidene bis‐barbituric acid derivatives
Authors: Jursic Branko S. , Neumann Donna M.
Published: March 2009

NMR reaction following experiments were used to find optimal conditions for the barbituric acid double addition to aromatic and heteroaromatic carboxaldehydes. It was established that aromatic aldehydes with electron‐donating substituents such as hydroxy, methoxy, and dimethylamino produce only the single addition barbituric acid adduct (barbituric acid benzylidenes). If these electron‐donating substituents are transformed into electron‐withdrawing substituents by virtue of protonation (NMe2 to NHMe2+) then the double barbituric acid adduct becomes the sole product of the reaction. This is also true regardless of the reaction media if strong electron‐withdrawing substituents (such as a nitro group) are present. Considering that the reactive species for nitrogen containing aromatic heterocycles are actually the conjugated acids (electron deficient molecule) only the double barbituric acid adducts are isolated. All synthetic procedures presented are applicable to multi‐gram scale preparations of double barbituric acid adducts.
A study of substituent effect on 1H and 13C nmr spectra of N‐ and C‐substituted carbazoles
Authors: Bonesi Sergio M. , Ponce Maria A. , Erra‐Balsells Rosa
Published: March 2009

1H and 13C nmr spectra of several N‐ and C‐substituted carbazoles (Series 1, 2, 3 and 4) were measured. Correlations between chemical shifts and substituent constants show that these parameters describe properly the substituent effect on the nmr phenomena. Atomic charge densities for carbazoles of Series 1, 2, 3 and 4 were calculated by using the semi empirical PM3 method. These values also show a linear correlation with the 13C chemical shifts. The synthesis of several carbazole derivatives 1a – 1g, 2a – 2g, 3a – 3j and 4a – 4g have been carried out according to literature procedures. The carbazoles 3i, 3j and 4c have been synthesized and fully characterized for the first time.
Enaminones as building blocks in heterocyclic synthesis: New syntheses of nicotinic acid and thienopyridine derivatives
Authors: Abdelkhalik Mervat Mohammed , Eltoukhy Afaf Mohammed , Agamy Samia Michel , Elnagdi Mohammed Hilmy
Published: March 2009

Reacting 1,3‐diphenyl‐propan‐2‐one with equimolecular amount of dimethylformamide dimethylacetal afforded the enaminone 4. This when reacted with another equimolecular amount of dimethylformamide dimethylacetal afforded the dienaminone 5. Compound 4 condenses with cyanothioacetamide and with cyanoacetamide to yield 2‐thioxo‐ and 2‐oxo‐pyridine‐3‐carbonitrile derivatives 6a,b respectively. Compound 6a reacted with α‐chloroacetone 8 to yield the thieno[2,3‐b]pyridine derivative 10 that cyclized further into 4,7,8‐trisubstituted pyrido[2′,3′:2,3] thieno[4,5‐d]pyrimidine 12. Compound 4 also afforded 2,5,6‐trisubstituted nicotinic acid ethyl ester 13 by reaction with ethyl acetoacetate in acetic acid in the presence of ammonium acetate. The dienaminone 5 reacted with acetic acid, ammonium acetate/acetic acid, phenylhydrazine and 5‐amino‐3‐methylpyrazole yielding 3,5‐diphenyl‐pyran‐4‐one 15a, 3,5‐diphenyl‐1H‐pyridin‐4‐one 15b and 1,3,5‐trisubstituted pyridin‐4‐ones 16a‐b.
Synthesis and characterization of new biologically active 2‐(1,3‐disubstituted pyrazolyl)chromones and corresponding pyrimidine, thiopyrimidine, pyrazolyl derivatives
Authors: Joshia N. S. , Karale B. K. , Gill C. H. , Bhirud S. B.
Published: March 2009

A series of 2‐(1‐methyl‐3‐n‐propylpyrazol‐5‐yl)‐chromones with interestingPhosphodiesteraseIV inhibitition activities were synthesized. Different derivatives of the titled compounds like aminopyrimidine, thiopyrimidine, pyrazolyl were synthesized and theirPhosphodiesteraseIV inhibitition activities were checked.
A facile one‐pot synthesis of novel substituted 1,2,3,4‐tetrahydropyrimidine, part 2: Synthesis of 1‐(aralkyl/aryl)‐3‐(alkyl/aralkyl/aryl)‐5‐aroyl‐1,2,3,4‐tetrahydropyrimidines
Authors: Chanda Kaushik , Dutta Milan Ch. , Karim Enamul , Vishwakarma Jai N.
Published: March 2009

1‐(Aralkyl/aryl)‐3‐(alkyyaralkyl)‐5‐aroyl‐1,2,3,4‐tetrahydropyrimidines (2a‐c) have been synthesized by dethiomethylation of 5‐aroyl‐6‐methylthio‐1,2,3,4‐tetrahydropyrimidines (1a‐c). An alternative one‐pot synthetic strategy has been developed for the title compounds 2a‐t by the reaction of enaminones 3 with pri mary amine and formaldehyde in refluxing methanol in good yields.
Novel synthesis of thieno[2,3‐b]pyridine and substituted 2‐thienylthiourea derivatives as antibiotic agents
Authors: Al‐Omran Fatima , El‐Khair Adel A.
Published: March 2009

Derivatives of thieno[2,3‐b]pyridine, 2‐thienylthiourea, 2‐thienylurea, 2‐thienylacetamide incorporating the 2‐phthalimidomethyl moiety have been synthesized. The synthesized compounds were then investigated for antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. The compounds were also investigated for antifungal activity against Aspergillus niger and Fusarium oxysporium. The structures of the newly synthesized compounds have been established on the basis of their analytical and spectral data.
Synthesis of pinacol esters of 1‐alkyl‐1H‐pyrazol‐5‐yl‐ and 1‐alkyl‐1H‐pyrazol‐4‐ylboronic acids
Authors: Ivachtchenko Alexandre V. , Kravchenko Dmitry V. , Zheludeva Valentina I. , Pershin Dmitry G.
Published: March 2009

Starting from 1H‐pyrazol, a wide number of 1‐alkyl‐1H‐pyrazol‐4‐yl and 1‐alkyl‐1H‐pyrazol‐5‐ylboronic acids and their pinacol esters were synthesized and characterized. The key step in the described methodology is the regioselective lithiation of the pyrazole ring. The synthesized pinacolates are stable under prolonged storage and can be used as convenient reagents in organic synthesis.
Synthesis and antimicrobial activity of N‐(substituted)‐N‐[1,2,4,8,10,11‐hexachloro‐6‐oxido‐12H‐dibenzo(d,g)(1,3,2)‐dioxaphosphocin‐6‐yl]ureas
Authors: Haranath P. , Anasuyamma U. , Reddy P. Vasu Govardhana , Reddy C. Sureshx
Published: March 2009

Substituted dibenzo dioxaphosphocin‐6‐yl ureas were synthesized by reacting hexachlorophene (4) with different carbamidophosphoric acid dichlorides (3) in the presence of triethylamine in dry toluene at 45‐50 oC. Their IR, 1H, 13C and 31P NMR spectral data is discussed. These compounds were found to possess good antimicrobial activity.
Effect of temperature on lipid‐derived volatile compounds in boiled potato during storage
Authors: Blanch Gracia Patricia , Flores Gema , Ruiz del Castillo Maria Luisa
Published: March 2009

BACKGROUND: The aroma of boiled potatoes is greatly appreciated by consumers. Although it is formed by 150 volatile compounds, only a few seem to actually contribute to the characteristic aroma. In addition, potatoes have to be stored at a low temperature after harvest to guarantee a year‐round supply. However, even at low temperatures, tuber volatile composition is modified during storage. The aim of the present study was to investigate the effect of storage temperature on boiled potato volatile constituents, mainly focused on lipid‐derived components, by considering different varieties stored at 4 °C and 8 °C.

RESULTS: It was found that fewer lipid‐derived components were obtained when the potato tubers were stored at 4 °C rather than 8 °C. Specifically, the amounts of 2,4‐decadienal isomers and hexanal increased with the storage time, particularly at 8 °C. Similarly, pentanal and nonanal, which are autoxidation products, occurred to a greater extent at higher temperatures. In contrast, the levels of sugar‐derived compounds, in general, increased during storage at 4 °C rather than 8 °C as a result of higher content of sugars at low temperature.

CONCLUSION: The effect of storage temperature on lipid‐derived volatile components in boiled potato appears to depend on the variety studied. Generally speaking, lower temperatures during storage promote sugar content and, as a consequence, sugar‐derived products. At the same time, lower temperatures result in less lipid oxidation and, therefore, a fewer lipid‐derived compounds. Copyright © 2009 Society of Chemical Industry