A facile synthesis of 2‐amino‐1,3‐selenazole by reaction of N,N‐unsubstituted selenourea with ketone

2‐Dialkylamino‐1,3‐selenazoles were yielded by the reaction of N,N‐unsubstituted selenoureas with ketones in the presence of ferric chloride. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:88–92, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20180     

N1‐allyl‐3‐substituted‐6,7‐dimethyl‐1,2‐dihydro‐2‐quinoxalinone as key intermediate for new acyclonucleosides and their regioisomer O‐analogues

The key intermediates allyloxyquinoxaline 2a–c and N‐allylquinoxaline 3a–c were used to synthesize a number of acyclonucleosides whose chemical modifications include quinoxaline ring and the acyclic part is either N¹‐propanediol or 3‐hydroxy‐ propyl substituents and their O‐analogues. These compounds were characterized by elemental analysis, MALDI MS, and NMR data. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:280–288, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20203     

Condensation products of 1‐aryl‐4‐carboxy‐ 2‐ pyrrolidinones with o‐diaminoarenes,o‐aminophenol,and their structural studies

A series of 2‐substituted benzimidazoles, benzoxazoles were synthesized by the condensation reactions of 1‐aryl‐4‐carboxy‐2‐pyrrolidinones and aromatic ortho‐diamines or ortho‐aminophenol. Alkylation of benzimidazoles with iodoalkanes led to 1‐aryl‐4‐(1‐alkyl‐1H‐benzimidazol‐2‐yl)‐2‐pyrrolidin‐ ones or 1,3‐dialkylbenzimidazolium iodides. N‐Subs‐ tituted γ‐amino acids were prepared by the hydrolysis of 1‐aryl‐4‐(1H‐benzimidazol‐2‐yl)‐2‐pyrrolidinones in sodium hydroxide solution, followed by treatment with acetic acid. The structure of the synthesized pro‐ ducts was investigated using IR and ¹H, ¹³C NMR spectra, MM2 molecular mechanics, and AM1 semi‐ empirical quantum mechanical methods. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:47–56, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20171     

Aryloxy tetrazoles with axial chirality: Synthesis and partial resolution of 5‐(1‐(2‐methoxynaphthalen‐1‐yl)naphthalen‐2‐yloxy)‐1H‐tetrazole

5‐(1‐(2‐Methoxynaphthalen‐1‐yl)naph‐ thalen‐2‐yloxy)‐1H‐tetrazole as the first aryloxy tetrazole with axial chirality was synthesized. Partial resolution was achieved using (S)‐proline and methylbenzylamine as the resolving agents. Best results were obtained using methylbenzylamine with 75–85% ee. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:416–419, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20241     

Synthesis of novel N‐alkyl/aryl‐N′‐(4‐arylthiazol‐2‐yl)‐N″‐xylosyl guanidines

The reaction of 2,3,4‐tri‐O‐acetyl‐β‐D‐xylopyranosyl isothiocyanate ( 1 ) and 2‐amino‐4‐arylthiazoles ( 2 ) gave xylosylthioureas 3 . These thiourea derivatives reacted with alkyl/aryl amine in the presence of HgCl₂ to give a new series of N‐alkyl/aryl‐N″‐(4‐arylthiazol‐2‐yl)‐N″‐xylosyl guanidines 4 . Some of the synthesized guanidines were screened for their biological activity. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:688–694, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20379     

Two‐step syntheses of 3‐methyl and 3‐phenyl‐1,2,4‐benzotriazines

3‐Methyl‐1,2,4‐benzotriazine and some of its derivatives were prepared in moderate yields (50–70%) via a reductive cyclization by a PtO₂‐catalyzed hydrogenation of the corresponding 2‐nitrophenylhydrazones of the pyruvic acid. The latter compounds were obtained in yields higher than 90% by reacting 2‐nitrophenylhydrazines with sodium pyruvate salt. Three 3‐phenyl‐1,2,4‐benzotriazine compounds were also produced via a reductive cyclization by a Pt/C‐catalyzed hydrogenation of their corresponding 2‐nitrophenylhydrazono‐ethers in high yields (>70%). © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:166–172, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20200     

Synthesis of new benzo[h]‐ and benzo[f]chromeno[2,3‐b]‐pyridine‐5‐ones

A number of new benzo[h]‐ and benzo[f]chromeno[2,3‐b] pyridine‐5‐ones derivatives were synthesized from benzo[h]‐ and benzo[f]‐chromone‐carbonitriles and amino‐benzo[h]‐ and benzo[f]chromone‐carbaldehydes. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:2–7, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20152     

2‐Benzothiazolyl‐N‐(arenesulfonyl)‐sulfinimidoyl fluorides

2‐Benzothiazolyl‐N‐(arenesulfonyl)‐sulfinimidoyl fluorides were synthesized by the treatment of benzothiazolyl‐2‐sulfur trifluoride with sulfonamides. The reaction of 2‐benzothiazolyl‐N‐ (p‐toluenesulfonyl)‐sulfinimidoyl fluoride with tert‐ butylamine and morpholine gave 2‐benzothiazolyl‐ N‐(arenesulfonyl)‐sulfinimidoyl amides. The reaction of 2‐benzothiazolyl‐N‐(p‐toluenesulfonyl)‐sulfinimi‐ doyl fluoride or 2‐benzothiazolyl‐¹⁵N‐(p‐tosyl)sul‐ finimidoyl fluoride with S‐trimethylsilylbenzenethiol gave di(benzothiazolyl‐2) disulfide, fluorotrimethylsi‐ lane and N,N′‐bis(p‐toluenesulfonyl)‐N,N′‐bis(phenyl‐ thio)‐hydrazine or ¹⁵N,¹⁵N′‐bis(p‐toluenesulfonyl)‐¹⁵N, ¹⁵N′‐bis(phenylthio)‐hydrazine, respectively. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:352–356, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20102     

Syntheses,characterizations, and crystal structures of tri‐ and diorganotin (IV) derivatives with 2‐mercapto‐5‐methyl‐1,3,4‐thiadiazole

A series of organotin(IV) complexes with 2‐mercapto‐5‐methyl‐1,3,4‐thiadiazole (HL) of the type R₃ Sn(L) (R = Me 1 ; Bu 2 ; Ph 3 ; PhCH₂ 4 ) and R₂Sn(L)₂ (R = CH₃ 5 ; Ph 6 ; PhCH₂ 7 ; Bu 8 ) have been synthesized. All complexes 1–8 were characterized by elemental analysis, IR,¹H, ¹³ C, and ¹¹⁹Sn NMR spectra. Among these, complexes 1 , 3 , 4 , and 7 were also determined by X‐ray crystallography. The tin atoms of complexes 1 , 3 , and 4 are all penta‐coordinated and the geometries at tin atoms of complexes 3 and 4 are distorted trigonal–bipyramidal. Interestingly, complex 1 has formed a 1D polymeric chain through Sn and N intermolecular interactions. The tin atom of complex 7 is hexa‐coordinated and its geometry is distorted octahedral. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:353–364, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20215     

Synthesis,structure and cytotoxic activity of 2‐acetyl‐5‐trimethylsilylthiophene(furan) and their oximes

5‐Trimethylsilylderivatives of 2‐acetylthiophene and ‐furan have been regioselectively prepared by a one‐pot procedure from the corresponding 2‐acetylfuran or 2‐acetylthiophene using lithium N‐methylpiperazide (LNMP)–butyllithium–trimethylchlorosilane–water as the sequence of reagents. The ketones obtained were converted to the corresponding oximes. The structure of 2‐acetyl‐5‐trimethylsilylthiophene oxime (E‐isomer) has been studied by X‐ray diffraction. Formation of centrosymmetric dimers by means of H‐bonds has been observed. The intermolecular hydrogen bond O9? H…N8 length is 2.842(5) Å [H…N8 = 1.87 (6) Å, O9? H…N8 = 157(4)°]. Copyright © 2006 John Wiley & Sons, Ltd.     

Organoiodine(III)‐mediated efficient synthesis of new 3,9‐diaryl‐bis‐1,2,4‐triazolo[4,3‐a][4,3‐c]pyrimidines

Oxidation of bis‐2,4‐pyrimidinylhydrazones of various araldehydes with two equivalents of iodobenzene diacetate in dichloromethane provides an efficient and easy method for the synthesis of eight new 3,9‐diaryl‐bis‐1,2,4‐triazolo[4,3‐a][4,3‐c]pyrimidines. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:653–655, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20250     

New cyclization of N‐hydroxyiminoyl chlorides with N‐alkyl ethynesulfonamides: Synthesis of 4‐alkyl‐3‐aryl‐4,5‐dihydro‐1,5,2,4‐oxathiadiazepine‐5,5‐diones

N‐Hydroxyiminoyl chlorides reacted with N‐alkyl ethynesulfonamides in the presence of triethylamine in CH₂Cl₂ to afford the 4‐alkyl‐3‐aryl‐4,5‐dihydro‐1,5,2,4‐oxathiadiazepine‐5,5‐diones (3) as the major products together with N‐alkyl‐3‐aryl‐5‐isoxazolesulfonamides (4). © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 461–464, 1999     

Indium trichloride–catalyzed synthesis of some novel 2,2′‐(N,N′‐diarylamino)‐ 4,4′‐diaryl‐5,5′‐arylidenebisthiazoles and their insecticidal activity

A series of novel 2,2′‐(N,N′‐diarylamino)‐4,4′‐diaryl‐5,5′‐arylidene‐bisthiazoles 2 were rapidly and smoothly prepared in good yields by using non conventional techniques i.e. microwave or ultrasonic irradiation, through indium trichloride catalyzed electrophilic substitution reaction of 2‐(N‐arylamino)‐4‐arylthiazoles 1 with various arylaldehydes. All the synthesized compounds were characterized on the basis of their elemental analyses and spectral data (IR, PMR and Mass). The synthesized compounds were also evaluated for their insecticidal activity against Helicoverpa armigera and gave promising results. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:224–231, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20537     

Conformational analysis of 2‐alkyl‐4‐methyl‐2,6‐diphenyl‐2H‐thiopyran derivatives: A combined experimental and theoretical study

Some 2‐alkyl‐4‐methyl‐2,6‐diphenyl‐2H‐thiopyrans were synthesized, and the crystal structure of 2‐tert‐butyl‐4‐methyl‐2,6‐diphenyl‐2H‐thiopyran 1 was determined by single‐crystal X‐ray diffraction. X‐ray crystallographic analysis and ab initio HF/6‐31G(d) and B3LYP/6‐31G(d) calculations revealed a favorable nonplanar half‐chair conformation for these compounds in which two ethylene units were rotated relative to each other around the single bond. The most conspicuous feature was the orientation of alkyl and phenyl groups with respect to the S atom. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:142–147, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20192     

Soluble poly(ethylene glycol) supported efficient synthesis of 2,5‐disubstituted 1,3,4‐oxadiazoles and 1,3,4‐thiadiazoles

An efficient soluble poly(ethylene glycol) (PEG) supported liquid‐phase parallel synthetic method for 2,5‐disubstituted 1,3,4‐oxadiazoles and 1,3,4‐thiadiazoles is described. 2‐Aryl‐5‐(4′‐methoxycarbonylphenoxymethyl)‐1,3,4‐oxadiazoles and 2‐aryloxymethyl‐5‐(4′‐methoxycarbonylphenoxyacetamido)‐1,3,4‐thiadiazoles are synthesized in high yield and high purity using this polymer supported strategy. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:664–669, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20253     

A facile synthesis of new thieno[2,3‐b][1,4]thiazine derivatives starting from 2‐acylamino‐3,3‐dichloroacrylonitriles

Readily available 2‐acylamino‐3,3‐dichloroacrylonitriles are sequentially treated with methyl mercaptoacetate in the presence of sodium methylate and with sulfuric acid to furnish the methyl ester of 7‐amino‐2‐oxo‐3H‐thieno[2,3‐b][1,4]thiazine‐6‐carboxylic acid. Treating it first with triethyl orthoformate and then with ammonia or primary amines, the pyrimidine‐4‐one nucleus is annelated to the thienothiazine system, which is corroborated by spectroscopic methods and X‐ray diffraction analysis. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:411–415, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20232     

Utilization of α‐halocarbonyl compounds in the synthesis of thiazole,thiadiazole, and thiophene derivatives

The behavior of ethyl 2‐phenylthiocarb‐ amoyl acetate 1 toward a variety of several α‐halo‐ carbonyl compounds was investigated. Thus, reaction of 1 with α‐bromoketones, hydrazonoyl bromides, and 2‐chloro‐N‐arylacetamides afforded the corresponding dihydrothiazole, 1,3,4‐thiadiazole, and thiophene derivatives, respectively. The synthesis of thiazolidin‐4‐one 11 , thiazolidin‐5‐one 12 , and some azo derivatives of thiazolidin‐5‐one were described. 5‐Arylazothiazoles 17 and 19 were synthesized by condensation of hydrazonoyl bromides 3 with different thiourea derivatives. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:299–305, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20206     

6‐Polyfluoroacyl‐ and 6‐trichloroacetylnorkhellins: Synthesis and reaction with aromatic amines

Five new 6‐polyhaloacylnorkhellins were synthesized in high yields from diethoxymethyl acetate and the condensation products of khellinone with R_FCO₂Et and CCl₃COCl. Reaction of 6‐polyfluoroacylnorkhellins with primary aromatic amines yielded 6‐(arylaminomethylene)‐7‐hydroxy‐4,9‐dimethoxy‐7‐(polyfluoroalkyl)furo[3,2‐g]chroman‐5‐ones. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:99–103, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20174     

Dichotomy of 1,3‐dipolar cycloreversions in a tetrasubstituted 2,5‐dihydro‐1,3,4‐thiadiazole

The cycloaddition of diphenyldiazomethane ( 8 ) to 16 thioketones at 40°C which furnishes tetrasubstituted 2,5‐dihydro‐1,3,4‐thiadiazoles, is followed by rapid N₂ loss (see the preceding paper), with one exception: For the dihydrothiadiazole 10 , the N₂ extrusion is slower by a factor of 4900 than its formation from 8 and 2,2,6,6‐tetramethycyclohexanethione ( 7 ). This elimination of N₂ is a 1,3‐dipolar cycloreversion which affords a thiocarbonyl ylide + N₂ As a consequence of steric hindrance in the example of 10 , a concomitant second cycloreversion furnishes thiobenzophenone ( 12 ) and the diazocyclohexane derivative 13 in an equilibrium. The complex kinetic system of Scheme 2 is confirmed by the irreversible interception of 13 with thioketone 14 . The structural conditions for retarded N₂ extrusions from dihydrothiadiazoles are discussed. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:443–448, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20263     

Synthesis of new bridgehead heterocycles: Pyrimido[3′,2′:3,4]‐1,2,4‐triazino[5,6‐b]indoles

A new bridgehead nitrogen hetero‐ cycle viz. 11‐carboethoxy‐9‐oxo‐pyrimido[3′2′:3,4]‐1,2,4‐triazino[5,6‐b]indole 3 has been synthesized from 3‐azido‐5H‐1,2,4‐triazino[5,6‐b]indole 2 by its reaction with diethyl fumerate. The intermediate 2 was obtained by treating 3‐hydrazino‐5H‐1,2,4‐triazino[5,6‐b]indole with NaNO₂ in presence of polyphosphoric acid. A plausible mechanism for the formation of 3 has been formulated and discussed. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:272–276, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20199