Indian Journal of Chemistry

Sect. B:Organic Chemistry including Medicinal Chemistry

VOL. 41B

NUMBER 1

JANUARY 2002

CONTENTS

Rapid Communications

 

 

 

152

A short, formal synthesis of ()-2-pupukeanone

Using intramolecular rhodium carbenoid C-H insertion as the key reaction, a simple and short approach to 2-pupukeanone is described.

 

A Srikrishna* & P Ravi Kumar

 

 

 

 

 

 

 

154

Indium trifluoromethanesulfonate (In(OTf)3) A new catalyst for Beckmann rearrangement of ketoximes and facile dehydration of aldoximes

 

Indium trifluoromethanesulfonate and zinc trifluoromethanesulfonate are found to be an effective catalysts for the facile dehydration of aldoximes to nitriles and Beckmann rearrangement of ketoximes to anilides in excellent yields.

 

Dhiren C Barman, Mukut Gohain,

Dipak Prajapati & Jagir S Sandhu*

 

 

 

 

 

 

 

157

Highly selective deprotection of tert-butyl esters using ytterbium triflate as a catalyst under mild conditions

 

Ytterbium triflate catalyses the deprotection of tert-butyl esters selectively in the presence of other esters under mild conditions in almost quantitative yields. The reactions are carried out in nitromethane (450 - 50C) using 5 mole percent of the catalyst.

 

P Ramu Sridhar, Surajit Sinha & S ChandrasekaranV

 

Papers

 

161

Mechanistic investigation of asymmetric amino hydroxylation (AA) of alkenes

 

Transfer of nitrogen and oxygen in asymmetric aminohydroxylation (AA) has been examined. Electronic as well as steric effect on the nature of oxidizing agent and nitrogen source affect chemo, regio and stereoselectivity in AA reaction. A three cycle mechanistic pathway has been proposed. Results have been rationalized through an addition of alkene to Os=N bond in a [2+2] cycloaddition manner.

 

B B Lohray*, Vidya Bhushan,

G Jaipal Reddy & A Sekar Reddy

 

 

 

 

169

Synthesis of novel azo dyes derived from 4-phenylurazole

 

Some novel azo dyes 11a-e containing phenylurazole moiety have been synthesized from readily available starting materials.

 

Shadpour E Mallakpour* &
Hossein Nasr-Isfahani

 

 

 

 

 

 

 

175

Synthesis of some 2,7-disubstituted biphenylene and studies of their lithiation reactions

Synthesis of 2,7-disubstituted biphenylene including (i; R=OMe, F and NO2), and an investigation of their lithiation reactions is described. The study has been carried out in order to form reactive substituents at positions 1 and 8 or (4 and 5) and subsequent coupling to give derivatives of (ii).

 

A Larkem* & H Larkem

 

 

 

 

 

 

181

A convenient synthesis of an unsymmetrical biphenyl ether and its elaboration for the synthesis of Illicium neolignan isomagnolone

Isomagnolone 4 has been synthesized via the synthesis of the appropriate biphenyl ether which is an alternative to the conventional oxidative coupling route.

Atulya Kumar Panda

 

 

 

 

 

 

184

Synthetic confirmation for the structure of stipulin

 

Synthesis of stipuflavanone obtained from formic acid treatment of stipulin (5, 3-di-isopentenyl-2, 4, 4-trihydroxychalcone) has been accomplished by involving the following steps providing synthetic confirmation for the structure of stipulin.

 

Puspa Bhatt & Rameshwar Dayal*

 

 

 

 

 

 

 

187

Studies in the Friedel-Crafts Reaction: Part VI Synthesis and intra-, and inter- molecular Friedel-Crafts reaction of 2-methyl-4- phenylpentanedioic anhydride

The Friedel-Crafts reaction of 2-methyl-4-phenyl-pentanedioic anhydride 1 with aryl ethers gives 3 while intra-molecular reaction gives 2.

R S Natekar & S D Samant*

 

 

 

 

 

 

191

Diels-Alder reaction of pyran-2(H)-ones : Part VI Preparation and investigation of the Diels-Alder reaction of 4,6-disubstituted thiopyran-2(H)-ones with 1,4-naphthoquinone and N-phenylmaleimide

4,6-Disubstituted pyran-2(H)-ones 1 when treated with P2S5 the corresponding pyran-2(H)-thiones 2 are obtained. 2 on boiling in aq. methanol in the presence of Na2CO3 gives the corresponding thiopyran-2(H)-ones 3. The mechanism for this reaction has been proposed, which is supported by the AM1 calculation results and the spectral data. The Diels-Alder reactions of 2 and 3 with N-phenylmaleimide (NPMA) and 1,4-naphtho-quinone (NQ) have been studied.

 

Ruchira R Pai, Deven S Bendre & Shriniwas D Samant*

 

 

 

 

 

 

196

Photoreduction of benzophenone analogues by alcohol and ether: Self recognition molecular assemblies

Photoreduction of benzophenone analogues 1 to bezo-pinacol analogues 2 in 2-propanol and diethyl ether have been studied under various experimental conditions. Two analogues namely 1, 2-ethanediol, 1, 2-bis-(3, 4-dimethoxyphenyl)-1,2-diphenyl 2a and 1, 2-bis(1, 4-benzodioxin)-1,2-diphenyl 2b have been isolated and structurally characterized by X-ray crystallography.

 

H Mallesha, N D Dinesh, K S Rangappa*,
S Shashikanth, N K Lokanath, M A Sridhar &
J Shashidhara Prasad

 

 

 

 

 

 

 

201

Stability factors among fullerene C60 complete set isomers

 

 

 

Various factors affecting the stability of a complete set of isomers of fullerene C60 are investigated; among which, cage surface curvature, a factor that has not been paid attention much in the literature, is shown most responsible of the factors.

 

 

Mansour Zahedi*, Mohammed Al-Kobaisi &

Ali Al-Kobaisi

 

 

 

 

 

 

 

206

Reversal of substituent effects on electronic absorption spectra of N-(4-substituted phenyl)-benzamides in different solvents

 

 

 

Absorption spectra of eleven N-(4-substituted phenyl)-benzamides are recorded in ten solvents in the range 200-400 nm. The effects of substituents on the absorption spectra of investigated compounds are interpreted by correlation of absorption frequencies with simple and extended Hammett equation.

 

G Ućumlić* & S Petrović

 

 

 

 

Notes

 

 

 

211

An unexpected synthesis of 1H-perimidine 
X-ray crystal structure of 1H-perimidine hydrochloride dihydrate

 

 

 

Seik W Ng, Michael G B Drew, Golam Mostafa, Goutam K Patra & Dipankar Datta*

 

 

 

 

 

 

 

215

Microwave induced Friedlander condensation A facile synthesis of 1,8-naphthyridines
 
 

Synthesis of 1,8-naphthyridines 3 under microwave irradiation in open borosil vessels using unmodified domestic microwave oven is described.

 

K Mogilaiah* & N Vasudeva Reddy

 

 

 

 

 

 

 

218

Facile transformation of hydrazones to N-acyl-hydrazines with m-chloroperbenzoic acid in the solid state

 

 

Hydrazones 1 can be converted to the corresponding acylhydrazines 3 with m-chloroperbenzoic acid (m-CPBA) in the solid state.

 

 

K Mogilaiah*, H Ramesh Babu, R Babu Rao & N Vasudeva Reddy

 

 

 

 

 

 

 

220

Preparation of N,2-diaryldiazene-carboxamide under solvent-free condition using active manganese dioxide on acidic silica gel as the oxidant

 

 

An efficient and convenient oxidation of aryl substituted semicarbazides (ArNHCONHNHPh) to N, 2-diaryldiazenecarboxamides (ArNHCON=NPh) using active manganese dioxide on sulphuric acid silica gel under solvent-free conditions is described.

 

Hong Wang, Yulu Wang*, Gen Zhang & Jianping Li

 

 

 

 

 

 

222

Synthesis and antifungal activities of Schiff bases derived from 3-amino-2H-pyrano[2,3-b]-quinolin-2-ones

 

R=H or CH3 or OCH3

 

P Rajendran* & R Karvembu

 

 

 

 

 

 

 

225

Studies on the Himalayan yew Taxus wallichiana: Part IX The chemical constituents of the seeds of Taxus wallichiana

Cyanogenic glycoside 2 has been isolated as the major compound along with ursolic acid 1 and b‑sitosterol glucoside from the seeds of Taxus wallichiana. It is a very important finding that the seeds of Taxus wallichiana did not contain any taxoids.

1 2

 

 

S K Chattopadhyay*, V Tripathi,

K V Sashidhara, V K Mehta, B S Joshi &

R Roy

 

 

 

 

 

 

 

228

Studies on the new diterpene lactones from Rodgersia sambucifolia H.

Three new diterpene lactones,named as yantuine I 1,yantuine II 2 and yantuine III 3, have been isolated from Rodgersia sambucifolia H. (Chinese name yantuo,berberidaceae). Their structures have been determined on the basis of their spectral data and chemical studies.

1 R = COOH

2 R = COOMe

3 R = OAc

 

Shangzhen Zheng*, Hongang An, Tong Shen & Xuwei Shen

 

 

 

 

 

 

232

A new red pigment from an alkalophilic Micrococcus species

 

 

Isolation of a new tripyrrole pigment namely 2,2-[3-methoxy-1-amyl-5-methyl- 4-(1-pyrryl)] dipyrryl methene structurally analogous to prodiogiosins from an alkalophilic Micrococcus species is reported.

 

Prasad S Variyar*, R Chander,

S R Venkatachalam & D R Bongirwar

 

 

 

 

 

 

 

234

Triterpenes and triterpene glycosides from Salvia tricupis

 

 

Eighteen pentacyclic triterpenes and triterpene glycosides and three steroids have been isolated from Salvia tricupis. One of them is described for the first time as natural product, namely, 11-a-hydroxyurs-12-en-3-one 1.

 

Zhen-fu Hou, Zhi-xiang Xie, Yong-qiang Tu &

Yu Li*

 

 

 

 

 

 

 

Announcement

 

 

 

237

CSIR Young Scientist Awards for 2002
Shanti Swarup Bhatnagar Prizes in Science and Technology for 2002

 

 

Authors for correspondence are indicated by (*)