bluuebunny/crossref_metadata_2025_split huggingface dataset:
A cyclopropenone route to new pyrrolizidine derivatives
Authors: Kascheres Albert , Schumacher Heloisa C. , Rodrigues Reinaldo A. F. 
Published: April 2009

AbstractNew pyrrolizidine derivatives 6 and 7 were prepared from the 1, 5‐dihydro‐2H‐pyrrol‐2‐one 3a via an acidic intramolecular aldol condensation in 16% and 42% yields, respectively. Compound 6 was obtained by dehydration of 7 with p‐toluenessulfonic acid in 67% yield.
Ring transformation of 5‐amino (or acylamino)‐6‐hydroxy (or benzoyloxy)methylpyrimidin‐4(3H)‐ones into 1H‐imidazoles
Authors: Ueda Taisei , Asai Satoko , Oiji Khoji , Nagai Shin‐Ichi , Nagatsu Akito , Sakakibara Jinsaku 
Published: April 2009

AbstractTreatment of 5‐acylamino‐6‐hydroxy (or benzoyloxy)methyl‐3‐phenylpyrimidin‐4(3H)‐one 5,10 with 5% aqueous sodium hydroxide in ethanol gave 2‐alkyl‐5‐hydroxymethyl‐4‐phenylcarbamoyl‐1H‐imidazoles 7,11. Oxidation of 5‐amino‐6‐benzoyloxymethyl‐3‐phenylpyrimidin‐4(3H)‐one 9 in the presence of copper(II) chloride in alcohol gave 2‐alkoxy‐5‐alkoxymethyl‐4‐phenylcarbamoyl‐1H‐imidazoles 12a,b accompanied by 5‐amino‐6‐alkoxymethyl‐3‐phenylpyrimidin‐4(3H)‐ones 13a,b.
Synthesis of new type benzo[b]thiophene fused quinones and their tetracyanoquinodimethane derivatives
Authors: Ohba Yoshihiro , Murakami Yasuo , Sone Tyo , Awano Hiroshi 
Published: April 2009

AbstractA series of new type of benzo[b]thiophene‐fused 1,4‐benzoquinones and their tetracyanoquinodimethane derivatives were synthesized. The cyclic voltammetric data of new type quinones and tetracyanoquinodimethane derivatives displayed different behavior. All new quinones exhibit two reduction waves corresponding to the radical anion and dianion. On the other hand, most tetracyanoquinodimethane derivatives display a singlewave reduction to the dianion. The benzo[b]thiophene moiety fused tetracyanoquinodimethane derivatives reveal more negative reduction potentials than that of tetracyanoquinodimethane.
Thermolysis of N‐allylic 1,2,4‐triazoles
Authors: Carlsen Per H. J. , Jørgensen Kåre B. 
Published: April 2009

AbstractA number of 4‐allylic substituted 3,5‐diphenyl‐4H‐1,2,4‐triazoles were thermolyzed at 315–320° in evacuated glass ampoules. The main reaction in the melt was rearrangement to the corresponding 1‐substituted triazoles, which appeared to proceed via competing SN2 and SN2′ mechanisms. The allylic systems were observed to undergo [2,3]‐allyl walk reactions between the 1‐ and 2‐ring positions. Allyl to vinyl isomerization also took place. Substitution of the allylic moiety increased the rate of reaction but decreased the rate of isomerization of allylic to the vinylic substituted triazoles. The 4‐vinyl substituted triazoles were inert under the reaction conditions. Some triazoles were converted into substituted pyridines. This was proposed to proceed via nitrogen extrusion and formation of a 1,3‐dipolar intermediate (nitrile ylide) which added intramolecularly to the allyl moiety and subsequently aromatized to the pyridine.
Methyl 2‐[bis(acetyl)ethenyl]aminopropenoate in the synthesis of heterocyclic systems
Authors: Selič Lovro , Stanovnik Branko 
Published: April 2009

AbstractMethyl 2‐[bis(acetyl)ethenyl]aminopropenoate (4) was prepared in 3 steps from acetylacetone (1) via 4‐(N,N‐dimethylamino)‐3‐acetylbut‐3‐en‐2‐one (2) and methyl N‐[2,2‐bis(acetyl)ethenyl]glycinate (3). Compound 4 reacts with N‐ and C‐nucleophiles to give fused heterocyclic systems. Derivatives of pyrido[1,2‐a]pyrimidones 14–16 and thiazolo[3,2‐a]pyrimidones 17 and 18 were prepared from 2‐aminopyridines and 2‐aminothiazoles, respectively. With C‐nucleophiles derivatives of pyrido[1,2‐a]‐pyridinone 19 and 2H‐1‐benzopyran‐2‐one 20–22 were prepared.
Unexpected formation of a xanthone in the synthesis of a bisbenzoxazole
Authors: Dotrong My , Lovejoy Steven M. , Wolfe James F. , Evers Robert C. 
Published: April 2009

AbstractRecently we reported the synthesis in polyphosphoric acid of a graft copolymer consisting of a rigid‐rod poly[benzo(1,2‐d;4,5‐d′)bisthiazole‐2,6‐diyl]‐1,4‐phenylene backbone and flexible poly(oxy‐1,3‐phenylenecarbonyl‐1,4‐phenylene) side‐chains [1]. However, upon extension of this synthetic approach to the analogous graft copolymer with a poly[benzo(1,2‐d:5,4‐d′)bisoxazole‐2,6‐diyl]‐1,4‐phenylene backbone, we encountered some unexpected results due to methyl group migration. In order to better understand these results, we carried out the synthesis of selected benzothiazole and benzoxazole structures under appropriate reaction conditions. The results are reported in this article.
Urea cyclisation reaction studies
Authors: Niddam Valérie , Medou Martial , Dessolin Jean , Trabaud Carole , Camplo Michel , Kraus Jean‐Louis 
Published: April 2009

AbstractSynthetic approaches of N‐α‐hydroxyalkyl amides or urea derivatives are described. In particularly, a new 1,4,6‐oxadiazocine‐2,5,8‐trione was obtained by condensation of glyoxylic acid on urea derivatives in acidic catalysis condition.
Synthesis of chirally pure 2,5‐disubstituted diketopiperazines derived from trisubstituted phenylalanines
Authors: Danthi Satyavijayan Narasimhan , Hill Ronald A. 
Published: April 2009

AbstractSome new chirally pure 2,5‐substituted diketopiperazines were synthesized starting from 2‐methoxybenzyl alcohol. This multistep synthesis proceeds through the enzymatic synthesis of chirally pure amino acids, protection and dipeptide coupling, cyclization of dipeptide ester formates, and nitration of the resulting diketopiperazines.
Synthesis of new 1,2,3‐triazolo[1,2‐a]benzotriazole derivatives or substituted 2,3‐benzo‐1,3a,6,6a‐tetraazapentalenes. II
Authors: Biagi Giuliana , Giorgi Irene , Livi Oreste , Manera Clementina , Scartoni Valerio , Barili Pier Luigi 
Published: April 2009

AbstractThis paper continues the synthesis of new 1,2,3‐triazolo[1,2‐a]benzotriazoles or 2,3‐benzo‐1,3a,6,6a‐tetrazapentalenes to submit to biological assays. The derivatives were obtained by deoxycyclization reactions of appropriate nitrophenyl‐1,2,3‐triazole derivatives and by thermal decomposition of appropriate azidophenyl‐1,2,3‐triazoles (Schemes 1 and 2). Some attempts to extend these synthetic routes to the preparation of 1,2,4‐triazolo[1,2‐a]benzotriazoles (Scheme 3) and 1,2,3‐triazolo[1,2‐b]‐4H‐1,2,3‐benzo‐triazines (Scheme 4) completely failed.
Photocyclization reactions. Part 6. Solvent and substituent effects in the synthesis of dihydrobenzofuranols using photocyclization of 2‐alkoxybenzophenones and ethyl 2‐benzoylphenoxyacetates
Authors: Sharshira Essam Mohamed , Okamura Mutsuo , Hasegawa Eietsu , Horaguchi Takaaki 
Published: April 2009

AbstractPhotocyclization reactions were carried out on 2‐alkoxybenzophenones 1a‐h and ethyl 2‐benzoyl‐phenoxyacetates 5a‐e in three solvents of different polarity (benzene, acetonitrile and methanol) to examine solvent and substituent effects on the cyclization of 1,5‐biradical intermediates to dihydrobenzofuranols. Irradiation of 1a‐f in benzene gave dihydrobenzofuranols 4a‐f in 80–94% yields. The ratios of cis‐and trans‐isomers of 4b‐f were 12:1 to 1:0, showing stereoselective formation of cis‐isomers. On the other hand, irradiation of 1a‐f in acetonitrile and methanol gave 4a‐f in 68–81% and 7–75% yields, respectively. However, the ratios of cis‐ and trans‐isomers of 4b‐f were 3.5:1 to 1.3:1 in acetonitrile and 2.0:1 to 1:1.7 in methanol, showing decreased stereoselectivity. The decrease in stereoselectivity was attributed to intermolecular hydrogen bonding between the hydroxyl group of 1,5‐biradicals and solvents (acetonitrile and methanol). Similarly, irradiation of 5a‐e in benzene afforded cis‐dihydrobenzofuranols cis‐11a‐e stereo‐selectively. In contrast, irradiation of 5a‐e in acetonitrile and methanol gave a mixture of cis‐ and trans‐isomers of 11a‐e because of intermolecular hydrogen bonding between the hydroxyl group of 1,5‐biradicals and solvents. The cis and trans ratios of 11a‐e varied from 1.5:1 to 17.8:1 in acetonitrile and from 2.6:1 to 1:4.5 in methanol. Solvent and substituent effects on the cyclization of 1,5‐biradicals and reaction pathways are discussed.
On the synthesis and isolation of chlorocarbazoles obtained by chlorination of N‐substituted carbazoles
Authors: Bonesi Sergio M. , Erra‐Balsells Rosa 
Published: April 2009

AbstractChloro derivatives of N‐methylcarbazole (1), N‐phenylcarbazole (2), N‐acetylcarbazole (3), N‐benzoylcarbazole (4) and 2‐methoxy‐N‐methylcarbazole are synthesized. They are compounds 1a, 1b, 1c, 1d, 1e, 2a, 2b, 3a, 3b, 3c, 3d, 4a, 4b, 5a, 5b, 5c, 5d and 5e. Some of them are described for the first time. By using semiempirical PM3 method theoretical substituent effects on the chlorinating reaction are calculated. A chlorination mechanism of carbazoles and N‐substituted carbazoles are compared.
Furopyridines. XXII. Elaboration of the C‐substituents alpha to the heteronitrogen atom of furo[2,3‐b] ‐, ‐[3,2‐b] ‐, ‐[2,3‐c]‐ and ‐[3,2‐c]pyridine
Authors: Shiotani Shunsaku , Tanigochi Katsunori 
Published: April 2009

AbstractThe Grignard reaction of fused ring cyanopyridine derivatives 1a‐d with methyl‐ and phenylmagnesium bromide yielded the corresponding acylpyridine compounds 2a‐d and 3a‐d. Furopyridine N‐oxides 4a‐d were converted into the compounds having a phenyl group at the α‐position to the ring nitrogen 5a‐d. Reduction of 1a‐d and the carboxylic esters 6a‐d with diisobutylaluminium hydride yielded the corresponding amines 7a‐d and aldehydes 9a‐d. The aldehydes were converted to nitroethanol derivatives 10a‐d by condensation with nitromethane and acrylic ester compounds 11a‐d by the Wittig‐Horner reaction with methyl diethyl phosphonoacetate.
Synthesis of racemic and enantiomerically pure 2′‐thia‐2′,3′‐dideoxycytidine as potential anti‐hepatitis B virus agents
Authors: Pan Bai‐Chuan , Cheng Yung‐Chi , Chu Shih‐Hsi 
Published: April 2009

AbstractA novel class of nucleosides with the C1, atom bonded to three hetero atoms was synthesized. 2′‐Thia‐2′,3′‐dideoxycytidine was the pilot compound of this series. (±)‐β‐2′‐Thia‐1′,3′‐dideoxycytidine (6) and (±)‐α‐2′‐thia‐2′,3′‐dideoxycytidine (7) were synthesized from (±)‐3‐mercapto‐1,2‐propanediol. The synthesis of the enantiomerically pure 2′‐thia‐2′,3′‐dideoxycytidines (α‐D‐form, β‐D‐form, α‐1‐form and β‐L‐form) from optically pure (S)‐(2,2‐dimethyl‐1,3‐dioxalan‐yl)methyl p‐toluenesulfonate (8) and its (R)‐isomer 18 was also described. The preliminary biological results showed that (+)‐β‐D‐2′‐thia‐2′,3′‐dideoxycytidine (26) was the most active against human hepatitis B virus with an ED50 of 3 μM.
Cyclocondensation reactions of heterocyclic carbonyl compounds.. Synthesis of 2,6‐bis(6‐azauracil‐5‐yl)aniline and its use for synthesis of some other polynuclear 1,2,4‐triazines
Authors: Hlaváč Jan , Slouka Jan 
Published: April 2009

Abstract5‐(2‐Aminophenyl)‐6‐azauracil 1 was converted to 7‐(6‐azauracil‐5‐yl)isatin 3, semicarbazone 4 of which was recyclized to 2,6‐bis(6‐azauracil‐5‐yl)aniline 5. This one served as a starting compound for preparation of other noncondensed two nuclear heterocycles 7, 9, 10 and condensed 1,2,4‐triazines 11 and 12 as well.
Synthesis of tricyclic and tetracyclic thieno[3,2‐f]‐1,4‐thiazepines
Authors: Tanaka Hiroshi , Nakao Tohru 
Published: April 2009

AbstractTreatment of 5‐methylthio‐2,3‐dihydrothieno[3,2‐f]‐1,4‐thiazepine (9) with acylhydrazines gave 5,6‐dihydrothieno[3,2‐f]‐1,2,4‐triazolo[4,3‐d][1,4]thiazepines 10, 11, and that of 9 with ethyl anthranilate gave 5,6‐dihydrothieno[3′,2′:6,7][1,4]thiazepino[5,4‐b]quinazolin‐8‐one (14). Reaction of 9 with hydrazine hydrate or 4‐chlorophenylhydrazine afforded 5‐hydrazino compounds 12, 15, which were subsequently cyclized to ethyl 5,6‐dihydrothieno[3,2‐f]‐1,2,4‐triazolo[4,3‐d][1,4]thiazepine‐3‐carboxylate (13), 2‐(4‐chlorophenyl)‐5,6‐dihydrothieno[3,2‐f]‐1,2,4‐triazolo[4,3‐d][1,4]thiazepin‐3(2H)‐one (16) and 2‐(4‐chlorophenyl)‐6,7‐dihydro‐2H‐thieno[3,2‐f][1,2,4]triazino[4,3‐d][1,4]thiazepine‐3,4‐dione (17). New thieno‐anellated heterocycles were prepared with the aim of studying their affinity for the benzodiazepine receptors.
Synthesis and S‐methylation of 2‐thioxopyrido[3′,2′:4,5]thieno[3,2‐d]‐pyrimidin‐4(3H)‐ones with and without a phase transfer catalyst
Authors: Dave Chaitanya G. , Shah A. B. , Shah H. C. 
Published: April 2009

AbstractA number of 2‐thioxopyrido[3′,2′:4,5]thieno[3,2‐H]pyrimdin‐4(3H‐ones (5) have been synthesized by cyclocondensation of 2‐carbethoxy‐3‐amino‐4‐phenyl‐6‐substituted‐thieno[2,3‐b]pyridines (3) with various isothiocyanates. Compounds 5 were S‐methylated routinely and the reactions compared under solid‐liquid phase transfer conditions to obtain 2‐methylthiopyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidin‐4(3H)‐ones (6). The new triheterocyclic pyridothienopyrimidines were prepared with the objective to study their pharmacological properties.
Synthesis and structural study of novel 5‐aryl substituted 2‐amino‐4,7‐dioxopyrido[2,3‐d]pyrimidines
Authors: Rodríguez Rená , Suárez Margarita , Ochoa Estael , Pita Beatriz , Espinosa Remberto , Martín Nazario , Quinteiro Margarita , Seoane Carlos , Soto Jose L. 
Published: April 2009

AbstractThe tide compounds 4a‐c have been prepared in a one‐step procedure from 2,4‐diamino‐6‐hydroxy‐pyrimidine (1) and the corresponding arylidene substituted Meldrum's acids 2a‐e in very good yields. Semiempirical theoretical calculations (AMI) reveal two favoured conformations (A and B) for compounds 4a‐e. The 1H‐nmr determinations, by using Karplus and Altona equations, clearly indicate that conformation A, with the aryl group on C5 in a pseudoaxial position, is that predominant in solution. The calculated charge density values for the olefinic carbons are in agreement with the experimental push‐pull effect observed in the 13C‐nmr spectra.
Synthesis of pteridine derivatives related to folic acid and methanopterin from pyrazine‐2,3‐dicarbonitrile
Authors: Tada Masaru , Asawa Yasuhiro , Igarashi Mamoru 
Published: April 2009

AbstractPteridine derivatives related to folic acid and methanopterin were synthesized by two methods. The first synthesis is initiated by the radical substitution of 5‐methylpyrazine‐2,3‐dicarbonitrile (3) with the (N‐acylanilino)alkyl radical to give 6‐methyl‐5‐(N‐acylanilino)alkylpyrazine‐2,3‐dicarbonitrile (9) and was followed by the substitution of the 2‐carbonitrile with methylamine and further conversion to 1‐methyl‐2‐amino‐6‐(N‐acylanilino)‐alkyl‐7‐methylpteridin‐4(1H)‐imine 11 by the action of guanidine. The second method is initiated by radical hydroxymethylation of 5‐methylpyrazine‐2,3‐dicarbonitrile (3) to give 5‐hydroxy‐methyl‐6‐methylpyrazine‐2,3‐dicarbonitrile (15), followed by oxidation of the hydroxymethyl group, N‐phenylimination, and the substitution of the 2‐carbonitrile with methylamine to give 6‐methyl‐2‐methyl‐arnino‐5‐(N‐phenylimino)methenylpyrazine‐3‐carbonitrile (18). The reduction of the imino group and the final cyclization with guanidine gives 2‐amino‐6‐anilinomethyl‐1,7‐dimethylpteridin‐4(1H)‐imine (20).
Compounds based on meso‐tri(4‐pyridyl)‐p‐acrylamidophenylporphyrin able to interact with DNA
Authors: Li Handong , Czuchajowski Leszek , Trumble William R. 
Published: April 2009

AbstractA new type of porphyrinyl‐nucleoside was synthesized by the Heck reaction of meso‐tri(4‐pyndyl)‐p‐acrylamidophenylporphyrin with (+)5‐iodo‐2′‐deoxyuridine. The porphyrin used in this reaction was also applied in obtaining a water soluble porphyrin polymer and a copolymer with acrylamide. The porphyrinyl‐nucleoside and the polymer and copolymer were investigated for their interaction with ds DNA, oligonucleotides and oligonucleotide duplexes. The extend of the red‐shift of the Soret band of porphyrins and the slowing of the mobolity of DNA during electrophoresis of the interacting systems suggested that intercalation of cationic porphyrin units into ds DNA cannot be solely responsible for the observed phenomena.
13C‐NMR study of 4H‐1,3,4‐thiadiazino[5,6‐b]quinoxalines. A proof for the N5‐deuteration in deuteriotrifluoroacetic acid
Authors: Kim Ho Sik , Okamoto Yoshihisa , Kurasawa Yoshihisa 
Published: April 2009

AbstractThe carbon signals of the 2‐acylamino‐4H‐1,3,4‐thiadiazino[5,6‐b]quinoxalines 1a,b, 2‐acylamino‐4H‐1,3,4‐thiadiazino[5,6‐b]quinoxaline 1,1‐dioxides 2a,b, and 2‐amino‐4H‐1,3,4‐thiadiazino[5,6‐b]quinoxaline 3 in deuteriodimethyl sulfoxide and in deuteriotrifluoroacetic acid were assigned by the nmr (HMBC, HMQC) spectroscopy. The comparison of the carbon chemical shifts in deuteriodimethyl sulfoxide with those in deuteriotrifluoroacetic acid clarified that compounds 1a, 1b, and 3 were deuterized at the N5‐position in deuteriotrifluoroacetic acid, while the 1,1‐dioxides 2a,b did not undergo the N5‐deuteration in deuteriotrifluoroacetic acid.
Heterocyclic variants of the 1,5‐benzodiazepine system. VIII. Reaction of 4(7)‐aminobenzimidazole with ethyl 2‐alkylmalonates
Authors: Martínez Roberto , Valle Lucia , Gonzalez Marcos , Romano Claudia 
Published: April 2009

AbstractReaction of 4(7)‐aminobenzimidazole with ethyl 2‐alkylmalonates gave the novel 4,5,6,7‐tetrahydro‐5‐alkyl‐imidazo[1,5,4‐ef][1,5]benzodiazepine‐4,6‐diones, and the 2‐alkyl‐4(7)‐(2′‐ethoxycarbonyl)acetamido‐benzimidazoles. The structure of all the products was corroborated by ir, mass spectrometry and 1H‐nmr.
A new type of reaction between o‐phenylenediamines and aromatic aldehydes to give 2,3‐diarylquinoxalines
Authors: Ochoa Carmen , Rodriguez Juan 
Published: April 2009

AbstractA new type of reaction between o‐phenylenediamines and aryl aldehydes at high temperature is reported. The synthesis of 2,3‐diarylquinoxalines by this procedure is described.
Synthetic studies toward phenoxan analogs
Authors: Zhang Xiaowei , Hinkle Becky , Ballantyne Lisa , Gonzales Sam , Peña Michael R. 
Published: April 2009

AbstractWe developed two reactions needed for a total synthesis of phenoxan, a naturally occurring compound with anti‐HIV activity. In this Note, we further examined these two issues: metallation of a 2‐methyl‐oxazole and formation of a pyran‐4‐one. We employed these methods for the preparation of a phenoxan analog.
An improved process of separation of R‐ and S‐timolol
Authors: Várkonyi‐Schlovicskó Erika , Takács Kálmán , Hermecz István 
Published: April 2009

AbstractDiastereomeric timolol tartrates 4 are obtained in a one‐pot synthesis from the racemic base 2 and optically active O,O‐diacetyl‐ or O,O‐dibenzoyltartaric anhydrides 3, as only one of the diastereomers precipitates from acetone solution. Acidic hydrolysis as the corresponding 4 leads to timolol in high yield and optical purity.
The use of 4‐hetaryliden‐ and 4‐aryliden‐5(4H)‐oxazolones as dienophiles. Appropriate reagents for the synthesis of cyclic analogues of natural amino acids
Authors: Avenoza A. , Busto J. H. , Paris M. , Peregrina J. M. , Cativiela C. 
Published: April 2009

AbstractThis report describes the behavior of 4‐hetaryliden‐ and 4‐aryliden‐5(4H)‐oxazolones as dienophiles in the Diels‐Alder reaction with several dienes. The application of this reaction to the synthesis of different conformationally constrained cyclic analogues of natural amino acids of pharmacological interest is also described.
A simple one pot synthesis of 1‐(s‐triazolo[4,3‐x]azinyl‐3)‐substituted polyols
Authors: Svete Jury , Golič Ljubo , Stanovnik Branko 
Published: April 2009

AbstractOpen‐chain C‐nucleosides, 1‐(s‐triazolo[4,3‐x]azinyl‐3)polyols 13–18 were prepared by one‐pot synthesis from hydrazinoazines 20a,c and various D‐aldoses 1–6. No protective groups were required for these transformations. 1‐(s‐Triazolo[4,3‐b]pyridazinyl‐3)‐D‐xylo‐tetritol (15a) was isolated and characterised in the form of its 4‐O‐triphenylmethyl derivative 19. Reaction of hydrazinopyridazines 20a,b with methyl 2,3‐di‐O‐acetyl‐L‐threuronate (22), followed by treatment with bromine, gave the corresponding (2R,3S)‐2,3‐diacetoxy‐3‐(s‐triazolo[4,3‐b]pyridazinyl‐3)propanoic acid methyl esters 24a,b. Acetonisation of 1‐(6‐chloro‐s‐triazolo[4,3‐b]pyridazinyl‐3)‐D‐gluco‐pentitol (17a) gave a mixture of isomeric bis‐acetonides 25 and 26, while acetonisation of 1‐(6‐chloro‐s‐triazolo[4,3‐b]pyridazinyl‐3)‐D‐manno‐pentitol (18a) gave acetonide 27 as a single isomer.
Regiospecific synthesis of 6‐alkyltropan‐2‐ones
Authors: Lomenzo Stacey A. , Bradley Amy L. , Zhu Naijue , Klein Cheryl L. , Trudell Mark L. 
Published: April 2009

AbstractA new synthetic approach for the regiospecific alkylation of the 6‐position of the tropane ring system has been developed. Alkylation, desulfonylation and deprotection of tropanes 5 and 12 furnished a series of 6‐endo‐alkyltropan‐2‐one derivatives 8a‐e, 15a‐e and 16a‐e (R = Me, Et, n‐Pr, n‐Bu, Bn) stereoselectively in good yields. The 6‐endo isomers 15a‐e and 6‐exo isomers 16a‐e were easily obtained as pure diastereoisomers.
Synthesis of [1]benzothieno[3,2‐d]pyrimidines substituted with electron donating substituents on the benzene ring
Authors: Bridges Alexander J. , Zhou Hairong 
Published: April 2009

AbstractVarious 2‐fluorobenzonitriles were converted to the corresponding 3‐amino[1]benzothiophenecarboxylic acid esters, which in turn were annulated with formamidine or various equivalents to produce the desired tricyclic benzothienopyrimidines. Various methoxy and nitro/amino substituents were placed on the phenyl ring, requiring several different strategies to prepare the desired benzothiophenes. Several different pyrimidone annulations were also required. The use of an electron rich 2‐bromobenzonitrile in a four‐step one‐pot low temperature lithiation sequence to produce highly electron‐rich amino[1]benzothiophenecarboxylate esters is also described. The synthesis of 7‐amino‐8‐fluoro[1]benzothieno[3,2‐d]pyriinid‐4(3H)‐one was relatively straightforward, but synthesis of the corresponding 7‐amino‐8‐protio analogue proved to be very difficult, and required several approaches before a successful one was found.
Synthesis and characterization of new crown‐type compounds with 4‐pyrone Units
Authors: Löwe Werner , Brätter Stefanie , Dietrich Christoph , Weber Manuela , Luger Peter 
Published: April 2009

AbstractWe report here the syntheses and characterization of new crown‐type compounds 8 and 9 incorporated with one and two 4‐pyrone units. The reaction of compound 3 with 1,5‐bis(2‐hydroxyphenoxy)‐3‐oxapentane or catechol gave the desired molecules 8 and 9 in 65% and 25% yields, respectively. Compound 3 resulted from 1 by Wohl‐Ziegler bromination in small amounts and could be separated from five bromination by‐products by column chromatography. For example, 8 binds K+ and a pyrylium salt 11 (single crystal X‐ray structure analysis) can also be prepared starting from 3 by treatment of the latter with perchloric acid in the presence of acetonitrile.
2‐Azidopyrrolo[2,1‐c][1,4]benzodiazepines. Synthesis of the first cyclic amidine derivatives
Authors: Gillard Alain‐Claude , Rault Sylvain 
Published: April 2009

AbstractWe report the practical synthesis of the new 5‐azidopyrrolo[2,1‐c][1,2,4]triazolo[4,3‐a][1,4]benzo‐diazepin‐8‐one and 11‐alkylamino‐2‐azidopyrrolo[2,1‐c][1,4]benzodiazepines via the corresponding hydroxy compounds.
Synthesis of new hetero[2,1]benzothiazepine derivatives
Authors: Vega Salvador , Díaz Juan A. 
Published: April 2009

AbstractAs part of an investigation directed to the search of new neurotropic agents we have prepared a number of hydroxy and hydroximino derivatives of the novel thieno and pyrazolo[2,1]benzothiazepine ring systems. Assignments of the Z and E hydroximino isomers were performed by study of their 1H and 13C nmr spectra and NOE experiments.