Papers

751

Approaches to sesquiterpenes containing three contiguous quaternary carbon atoms. Synthesis of 3-methoxythapsene

IPC: Int.Cl.⁷ C 07 C 13/10

Stereoselective synthesis of (±)-3-methoxythaps-8-ene has been accomplished starting from Hagemann's ester.

A Srikrishna* & D B Ramachary

762

Cobalt (II) chloride or manganese (II) chloride or tin (II) chloride promoted one pot synthesis of dihydropyrimidin-2(1H)-ones using microwave irradiation

IPC: Int.Cl.⁷ C 07 D 239/00

Various substituted 3,4-dihydropyrimidin-2(1H)-ones have been synthesized in a one pot reaction of b-ketoesters, aldehydes and urea using cobalt chloride hexahydrate or manganese chloride tetrahydrate or tin chloride dihydrate under microwave irradiation in excellent yields without the addition of any proton source or any additive and without any side reactions as observed by Biginelli and others.

Sanjay Kumar, Anil Saini & Jagir S Sandhu*

768

Chloramine-T mediated synthesis of 1,3,4-oxadiazolyl-1,8-naphthyridines under microwave irradiation

IPC: Int.Cl.⁷ C 07 D

Rapid and efficient method for the synthesis of 1-(5-aryl-[1,3,4]oxadiazol-2-ylmethyl)-3-(o-chloro-phenyl)-1H-[1,8]naphthyridin-2-ones 5 using chloramine-T under microwave irradiation is described.

K Mogilaiah* & Ch Srinivas Reddy

773

Tighter ion pair effect and scale-up study in microwave assisted aminolysis of enolizable esters using potassium tert-butoxide (t-BuOK)

IPC: Int.Cl.⁷ C 07 C 67/00

Vivek Polshettiwar & M P Kaushik*

778

Ultrasound promoted deoximation by FeCl₃: A highly efficient, mild and expeditious approach

IPC: Int.Cl.⁷ C 07 C 251/32

The deoximation of aldoximes and ketoximes to afford corresponding aldehydes and ketones by anhyd. FeCl₃ in dry CH₃CN under ultrasound irradiation at 40 KHz has been reported. The method is highly efficient and applicable for both aromatic and aliphatic substrates. The conditions avoid the Beckmann rearrangement and the yields are excellent.

Ramesh Naik & M A Pasha*

783

Synthesis and pharmacological evaluation of heterocycles from benzocycloheptenones

IPC: Int.Cl.⁷ C 07 C 13/24

A new series of benzocyclohepten-5-one thiosemi­carbazones 2a,b obtained by condensation of benzo­cyclohepten-5-ones 1a,b with thiosemicarba­zide, are treated with monochloroacetic acid, 3-bromo­pro­pionic acid, chloroacetyl chloride, 1,3-dichloro­acetone, phenacyl bromide and acetic anhydride, respectively to yield nitrogen and sulphur containing heterocycles.

Peesapati Venkateswarlu* &

Nageswara Rao Vasireddy

789

Synthesis of novel naphtho[2,1-b]furo-pyrazolyl, isoxazolyl and pyridyl derivatives as potential antimicrobial agents

IPC: Int.Cl.⁷ C 07 D 231/00, 261/00, 213/00

// A 61 P 31/04, 31/10

The title compounds 3-(3-aminonaphtho[2,1-b]fur-2-yl)-5-arylpyrazolines 3a-l, 3-(3-aminonaphtho[2,1-b]fur-2-yl)-5-arylisoxazolines 4a-f and 2-amino-3-cyano-4-aryl-6-(3-aminonaphtho[2,1-b]fur-2yl)pyri­dines 5a-f are synthesized from 1-(3-amino­naphtho[2,1-b]furo-2'-yl)-3-aryl-2-propen-1-ones 2a-f by reacting them with substituted hydrazine, hydro­xyl­amine hydrochloride and malanonitrile, respectively and screened for antimicrobial activity.

K M Mahadevan, K M Basavaraj

D A Prathima Mathias & V P Vaidya*

794

Chemoselective reaction of benz[g]indole dicar­bo­­xylate towards hydrazine hydrate: Bishetero­cycles: Synthesis and antimicrobial activity of some new 1-[2-hydroxyethyl]-3-ethoxycarbonyl-5-oxadiazolyl/triazolyl/pyrrolylaminocarbonyl­meth­oxy-2-methylbenz[g]indoles

IPC: Int.Cl.⁷ C 07 D 209/04

Manjunath G Bhovi & Guru S Gadaginamath*

801

Glucosylation of 4¢-hydroxychalcones using glu­co­syl donor

IPC: Int.Cl.⁷ C 07 H 19/00

Condensation of α-acetobromoglucose with 4¢-hydro­xy­arylmethyleneacetophenone derivatives (chalcones) in anhydrous acetone furnishes 2,3,4,6-tetra-O-acetyl-4¢-O-β-d-glucopyranosyloxychalcones 3a-i. Deblocking of the latter with CH₃ONa in dry methanol affords 4¢-O-β-d-glucopyranosyloxychalcones 4a-i.

V N Ingle*, S T Kharche & U G Upadhyay

806

Isolation and hypotensive activity of five new phytoconstituents from chloroform extract of flowers of Hibiscus rosasinensis Linn.

IPC: Int.Cl.⁷ A 61 K

Hypotensive activity of five new compounds 1-5 isolated from different extracts of Hibiscus rosasinensis Linn is observed. Their structures have been established on the basis of spectral data.

Anees A Siddiqui*, Sachin M Wani, R Rajesh &

V Alagarsamy

Notes

812

Synthesis of 1,3-diaryl-4-(pyridin-4-yl)­pyra­zoles as a new class of pyrazole based diaryl heterocycles

IPC: Int.Cl.⁷ C 07 D 231/00

A number of 1,3-diaryl-4-(pyridin-4-yl)pyrazoles 3a-j have been synthesized from 1,3-diaryl-4-carboxalde­hyde 4 as a new class of pyrazole based diaryl heterocycles.

G Jagath Reddy*, K Pallavi, R Shailaja Reddy & K Srinivasa Rao

815

A facile synthesis of indolo[3,2-c]xanthones

IPC: Int.Cl.⁷ C 07 D 209/04

T Vandana & K J Rajendra Prasad*

819

Synthesis of biogenetically possible 2-phenyl-4-oxopyrano[2,3-a]carbazoles

IPC: Int.Cl.⁷ C 07 D 209/82

T Vandana & K J Rajendra Prasad*

823

One pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones/-thiones catalysed by zinc chloride: An improved procedure for the Biginelli reaction using microwaves under solvent free condition

IPC: Int.Cl.⁷ C 07 D 239/00

Zinc chloride efficiently catalyzes the three-component coupling of β-keto ester, substituted aldehyde and urea or thiourea to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones, the new protocol for the Biginelli reaction under microwave irradiation works in the absence of solvent, the yields are high and the reaction goes to completion within 20-35 sec.

M A Pasha*, N Ramachandra Swamy &

V P Jayashankara

827

A domino type one-flask synthesis of 1-substi­tuted-5-aminoimidazole-4-carboxamides and ring transformation to pyrazine under microwave through suitable aminoimidazoliumcarboxamide

IPC: Int.Cl.⁷ C 07 D 233/54

Reductive heterocyclisation of oximinocyanoaceta­mide 1 affords 1-substituted-5-aminoimidazole-4-car­bo­xa­mides 2. 4c generated in situ from 2i, furnishes a ring expanded 3-(1-amino-1-diphenyl­methyl­amino)­methyleno-2-oxo-6-phenyl-pyrazine 5 with methano­lic alkali under microwave in excellent yield.

R = p-tolyl, p-anisyl, p-chlorophenyl, 2-thiazolyl, p-sulphonamidophenyl, phenyl, benzyl, methyl,

 diphenylmethyl

Gautam Chattopadhyay* & Tapas K Saha

831

Microwave-assisted deoximation under solvent-free conditions using Bi(NO₃)₃.5H₂O supported onto montmorillonite K-10

IPC: Int.Cl.⁷ C 07 C

Oximes are oxidatively deprotected by bismuth nitrate supported onto montmorillonite K-10 to the parent carbonyl compound in high yields upon exposure to microwave irradiation in solventless system.

Mohammad M Mojtahedi* & Majid M Heravi

834

Novel synthesis and antibacterial activity of 15-imino benzothiazolo[2,3-b]pyrimido[5,6-e]pyri­mido[2,3-b]benzothiazol-14(H)-one and its 3,10-disubstituted derivatives

IPC: Int.Cl.⁷ C 07 D // A 61 P 31/04

Novel heterocyclic compound 15-imino pyrimido­[5,6-e]pyrimido[2,3-b]benzothiazol-14(H)-one and its 3,10-disubstituted derivatives 3a-l have been synthe­sized and screened for antibacterial activity.

K G Baheti, J S Jadhav, A T Suryavanshi&
S V Kuberkar*

838

Synthesis of some 1,2,4-triazoles as potential antifungal agents

IPC: Int.Cl.⁷ C 07 A 61 P 31/10

Some new 3-(p-substituted anilinoethyl)-4-(p-substi­tuted phenyl)-5-thioxo-1, 2, 4-triazoles 3a-p are synthesized and evaluated for antifungal activity against Candida albicans and Aspergillus niger.

R₁=H, OCH₃, Br, Cl

R₂=H, CH₃, Br, Cl

Anees A Siddiqui*, Amit Arora, N Siddiqui & Amit Misra

842

Stereochemistry of 3,4-dihydroexcelsin

IPC: Int.Cl.⁷ C 07 C 13/553

Hydrogenation of excelsin 1 furnishes 3, 4-dihydro­excelsin 2 which is found to be C-4 epimer of the naturally occurring 3, 4-dihydroexcelsin 3.

Anuj Pandey, Bipin Chandra Joshi, Satish Kumar,

Kanwal Raj, Ram Prakash Sharma* & Anakshi Khare

844

A simple and practical synthetic protocol for thioacetalization of carbonyl compounds

IPC: Int.Cl.⁷ C 07 C 49/00

R₁ = aryl, alkyl, sugar residue; R₂ = H, alkyl, aryl

R₃ = Et, Ph,-(CH₂)_n;  n = 2, 3

Abu T Khan* & Ejabul Mondal

Authors for correspondence are indicated by (*)

IPC: International Patent Classification

Int. Cl.: International Classification 7 edition, 1999