Indian Journal of Chemistry

Sect. B: Organic Chemistry including Medicinal Chemistry

Total visitors: 1,352  since 20-11-07

VOL. 46B

NUMBER 10

OctOber 2007

CONTENTS

Papers

1645

Tandem reductive cyclisation of diethyl 2-(2-nitro-1-arylethyl) malonate by zinc and ammonium chloride in aqueous medium

A tandem reductive cyclaisation of diethyl 2-(2-nitro-1-arylethyl)malonate by zinc and ammonium chloride in aqueous medium leading to a one pot synthesis of ethyl 2-oxo-4-arylpyrrolidine-3-carboxylate in good yield has been described.

S R Jayapradha & S Muthusubramanian*

1648

A carbohydrate-based synthesis of fused bicyclic ethers by radical cyclization of epoxides using titanocene(III) chloride

A carbohydrate-based synthesis of both cis- and trans-fused bicylic ethers has been achieved by radical cyclization of epoxides using a transition-metal radical source. Thus, 6-exo radical cyclizations of the carbohydrate derivatives using [bis(cyclopentadienyl) titanium(III)]chloride (Cp₂TiCl) as the radical source has resulted in corresponding cis- and trans-fused bicyclic ethers. While the trans-fused compound has allowed stereoselective radical cyclization, the cis-fused has ended up only in a mixture of isomers. The functionalities present in the bicyclic compounds are potential intermediates as multifunctional conformationally rigid scaffolds.

S Jana, C Guin & S C Roy*

1658

Synthesis and characterization of 5,10,15,20-tetra(N-ethyl-3-carbazoyl) porphyrin

The porphyrin has been characterized by ¹H NMR, FAB-HRMS, UV-visible spectrophotometry and electrochemistry. The spectral data are found to be in agreement with the proposed structure.  Trends observed in the oxidation and reduction potentials are consistent with the nature of the porphyrin.

C P Tidwell*, L A Alexander, L D Fondren,

K Belmore & D E Nikles

1666

Synthesis of benzoxazole-2-ones, benzothiazole-2-ones and their  2-thione derivatives: Efficient
conversion of 2-thione to 2-oxo derivatives

A highly practical procedure for preparing benzoxazole-2-ones, benzothiazole-2-ones and its 2-thione derivatives using ethylchloroformate and carbon disulfide and the corresponding
aminophenols and aminothiophenols as the starting materials in one-pot protocol is presented. The yields vary from good to excellent, the conditions are mild, and the use of toxic and harmful chemicals is avoided. An efficient conversion of
benzoxazole-2-thione to 2-one derivative in high yield has also been carried out.

M S Singh*, Pallavi Singh & Shweta Singh

1672

SDS/CH₂(CN)EWG/H₂O: An efficient and green system for the cleavage of nitrones and imines in water

Saikat Das Sharma, Pranjal Gogoi &
Dilip Konwar*

1679

N and N+1 Cap positional effects of (D)alanine in the 3₁₀ type helical model peptide Boc-(D)Glu₁-Ala₂-Ala₃-Lys₄-NHMe

The N (Ala₂) and N+1 (Ala₃) cap positional alanine in the 3₁₀ helical model peptide Boc-(D)Glu₁-Ala₂-Ala₃-Lys₄-NHMe 2 is substituted with a D alanine. An NMR enquiry confirms the appreciable ordering of peptide 2, against its (L)Glu₁ analog, and  establishes  that (D)alanine partially disorders the type II’ turn templated 3₁₀ type helical fold  in a position dependent manner.

V D Bobade* & P C Mhaske 

1686

Synthesis and evaluation of phenyl substituted sydnones as potential DPPH-radical scavengers^!

A series of phenyl substituted sydnones have been synthesized and their radical-scavenging activity have been studied on DPPH free radical.

Shanta G Mallur, A K Tiwari, B China Raju,
K Suresh Babu, A Zehra Ali, B S Sastry &
J Madhusudana Rao^a*

1690

Aluminium(III) halides mediated synthesis of
5-unsustituted 3,4-dihydropyrimidin-2(1H)-ones via three component Biginelli-like reaction

5-Unsubstituted-3,4-dihydropyrimidin-2(1H)-ones have been synthesized in excellent yields in a aluminium(III) halides mediated three component cycloaddition of aldehyde, urea and enolizable ketone

Anil Saini, Sanjay Kumar & Jagir S Sandhu*

1695

Novel acid catalysed rearrangement of duloxetine

Veera Reddy Arava*, Udaya Bhaskara Rao Siripalli &

Srinivas Reddy Bandatmakuru

Notes

1699

Synthesis and anti microbial activity of quinoxaline based thiazolidinones and azetidinones

Several 2-aryl-3-(3¢-methyl quinoxalin-2¢-yl-amino)-4-thiazolidinones 6a-l and 1-N- (3¢-methyl quinoxalin-2¢-yl-amino) 4-aryl-3-chloro-2-azetidinones 7a-l have been synthesized and tested for their antibacterial antifungal activity against different microorganisms. The structures of compounds 6a-l and 7a-l have been confirmed on the basis of elemental analysis and spectral data.

D A Vyas*, N A Chauhan &A R Parikh

1703

One-pot multicomponent synthesis of some novel acridines

Acridine derivatives 1b-5b have been synthesized from dimedone, 1,3-cyclohexanedione, cyclohexanone and phenols by reacting each with vinyl acetate in
2% sodium hydroxide followed by treatment with ammonia.

V Nadaraj, S Kalaivani & S Thamarai Selvi*

1707

Synthesis and studies of some novel s-triazine based aminopyrimidines, isoxazoles and 1,5-benzo-thiazepines

Chalcones, 2,4-bis-(phenylamino)-6-[4¢-{3¢¢-(phenyl/sub-stituted phenyl)-2¢¢-propenon-1¢¢-yl}-phenyl amino]-s-triazines 6a-e have been prepared from ketone 5 based on s-triazine nucleus. These chalcones 6a-e on cyclisation with guanidine nitrate, hydroxylamine hydrochloride and 2-aminothiophenol gives the corresponding aminopyri-midines 7a-e, isoxazoles 8a-e and 1,5-benzothiazepines 9a-e, respectively. They are characterized by elemental analysis, IR, ¹H NMR and lc mass spectral data.

Anjani Solankee*, Kishor Kapadia,
Pankit Solankee, Yogesh Prajapati, Hiral Patel &
Sejal Solankee

1713

Dehydroacetic acid and its derivatives in
organic synthesis: Synthesis of some new
2-substituted-4-(5-bromo-4-hydroxy-6-methyl-
2H-pyran-2-one-3-yl)thiazoles

Synthesis of 3b,3b,5-tribromoacetyl-4-hydroxy-6-methyl-2H-pyran-2-one 2 from the bromination of DHA 1 in chloroform has been reported. The reaction of 2 with various thioureas/thioamides leads to an efficient synthesis of new 2-substituted-4-(5-bromo-4-hydroxy-6-methyl-2H-pyran-2-one-3-yl)thiazoles.

Richa Prakash, Ajay Kumar, Shiv P Singh,
Ranjana Aggarwal & Om Prakash*

1716

Clay-catalyzed high-speed synthesis of thiadiaze-pine in one-pot

Clay catalyzed synthesis of 4,4¢-bis[{6¢¢,8¢¢-diphenyl (substituted/
unsubstituted)-7¢¢,8¢¢-dihydro [1,2,4] triazolo[3,4-b][1,3,4]-thiadiazepin-3¢¢yl}methoxy]bi-benzyls 4a-m under microwave irradiation with excellent yield has been reported. Antifungal screening results of 4a-m on Fusarium oxysporum and Penicillium citrinum show that most of the synthesized compounds display promising antifungal activity.

I R Siddiqui*, Pravin K Singh, Vishal Srivastava & J Singh

1721

Al₂O₃ catalyzed Friedlander synthesis of 1,8-naph-thyridines in the solid state

Al₂O₃ catalyzes efficiently the Friedlander condensation of
2-aminonicotinaldehyde 1 with various carbonyl compounds containing a-methylene group 2 in the solid state at room temperature to afford the corresponding 1,8-naphthyridines 3 in good yields.

K Mogilaiah* & K Vidya

Authors for correspondence are indicated by (*)